[clug] Virt-Manager & snapshots Vs Xen

[George]

I was using KVM with Virt-Manager under Centos 7 and Debian Wheezy and
when I went to take a snapshot of a 6 TB server before applying
updates, and found that there was no snapshot support. For me
snapshots are a base requirement for any virtual machine. For example,
before applying any updates to a virtual server, take snapshot,
install updates, test running software to see nothing as broken,
delete snapshot while consoldiating image, or if the changes cause
issues, roll back the image to the snapshot and live without the
updates until you can apply them without causing issues.

Searching on the Internet I discovered that Virt-Manager >= version
1.0 can take snapshots if the image is qcow2.

http://blog.wikichoon.com/2014/03/snapshot-support-in-virt-manager.html
The biggest feature we added in virt-manager 1.0 is VM snapshot
support. ... Only works with qcow2 disk images. ... While the overlay
files have to be qcow2, these snapshots will work with any base disk
image. They can also be performed with very little VM downtime, at
least under a second.

When checking both Debian Jessie and CentOS 7, I discovered that
Virt-Manager was < version 1.0, so using standard packages was not
going to be a useful solution. I will be pleased with these OSs
upgrade to a virt-manager that can support snapshots,but it could be a
long while away.

Going to the Virt-Manager home page, I downloaded the latest verison
of the source code, "virt-manager 1.1.0 Sunday September 07, 2014",?
http://virt-manager.org/download/


"To build an RPM, you can run:??? python setup.py rpm"
When I attempted to compile an RPM for CentOS 7, the compile failed
with "Requires: libosinfo >= 0.2.10".


ftp://ftp.isu.edu.tw/pub/Linux/Fedora/linux/releases/test/21-Alpha/Workstation/x86_64/os/Packages/l/libosinfo-0.2.11-1.fc21.x86_64.rpm
http://pkgs.org/fedora-21/fedora-x86_64/libosinfo-0.2.11-2.fc21.x86_64.rpm.html
http://dl.fedoraproject.org/pub/fedora/linux/development/21/x86_64/os/Packages/l/libosinfo-0.2.11-2.fc21.x86_64.rpm

The above provided an RPM for libosinfo which allowed Virt-Manager to
compile.

Now I if I create a qcow2 based virtual machine, I can take snapshots,
though I have not yet had time to test the stability or effectiveness
of these snapshots.

I would be interested in peoples comments on the above.

I originaly dismissed Xen as I believed it was tied to a commercial
company, and not completely open to the Open Source community.? If I
am wrong please correct me. Also let me know what type of management
interface Xen can use.
http://en.wikipedia.org/wiki/Xen
The Xen community develops and maintains Xen as free and open-source
software, subject to the requirements of the GNU General Public
License (GPL), version 2.

[George]

What are you using for an FOSS or OpenSource Hypervisor and Management
GUI,_ if you are using any_? .

http://en.wikipedia.org/wiki/Free_and_open-source_software
Free and open-source software (FOSS) is computer software [1] that can
be classified as both free software [2] _and_ open source software
[3].

I am still a little confused regards the differences between Xen and
XenServer. Xen could be the community edition of XenServer which is
the propriety Citrix version which they may have also released to Open
Source while offering paid support (I found conflicting statements
regards the "open"ness of XenServer).

I am Looking for a FOSS GUI management tool for Xen that was not tied
to a commercial version was very difficult. Maybe Ganeti, OpenNebula
or OpenXenManager ?
http://wiki.xen.org/wiki/Xen_Management_Tools
https://github.com/OpenXenManager/openxenmanager
http://www.dedoimedo.com/computers/openxenmanager.html
???? OpenXenManager is an open-source multiplatform clone of
Citrix XenCenter. It is written in Python, using pyGTK for its
interface.
http://opennebula.org/about/contributors/
http://opennebula.org/about/project/
???? Since its first public release of software in March 2008, it
has evolved through open-source releases and now operates as an open
source project.
https://code.google.com/p/ganeti/

These products did not seem to match FOSS (FOSS would exclude words
like "price" and "license");
https://xen-orchestra.com/pricing.html
http://www.openqrm-enterprise.com/products/enterprise-edition/pricing-and-licensing.html
http://www.citrix.com/products/xenserver/buy.html (How to Buy
XenServer)
http://www.zentific.com/ (For questions, pre-sales...)
http://www.convirture.com/support_enterprise.php
http://www.convirture.com/support_opensource.php

====My research
notes==================================================

Open Source means that you have influence over the direction of the
code. You are not at the mercy of some immovable external organization
which may have priorities which do not align with your organization.
You can participate and help ensure that your needs are heard in the
process. And you never have to worry that some entity has decided to
terminate the product for business reasons. An Open Source project
will live as long as there are parties interested in advancing the
software.

Who Uses the Xen Project Code?

Our hypervisor has a user base in the millions, that include cloud
providers such as Amazon Web Services, Rackspace Hosting, Verizon
Cloud and many others. You may also want to check out the Directory
for vendors, products, projects, services and research related to the
Xen Project.

http://wiki.xenproject.org/wiki/Xen_Project_Beginners_Guide

http://www.openqrm-enterprise.com/resources/documentation-howtos/howtos/virtualization-with-xen-and-openqrm-51-on-debian-wheezy.html

http://sourceforge.net/projects/openqrm/files/latest/download

http://www.citrix.com/products/xenserver/overview.html

https://xen-orchestra.com/pricing.html
http://www.openqrm-enterprise.com/products/enterprise-edition/pricing-and-licensing.html
http://www.citrix.com/products/xenserver/buy.html (How to Buy
XenServer)
http://www.zentific.com/ (For questions, pre-sales...)
http://www.convirture.com/support_enterprise.php
http://www.convirture.com/support_opensource.php



http://xenserver.org/get-support.html
Citrix XenServer subscription offers customers 24x7 worldwide support,
commercial license protections and the ability to apply hotfixes via
the XenCenter user interface in a seamless and easy to understand way.


http://blogs.citrix.com/2013/06/25/xenserver-6-2-is-now-fully-open-source/

XenServer 6.2 is now fully open source!

It?s an exciting day for Citrix, our customers and the open source
community as we announce some BIG news for Citrix XenServer. Today we
cross another major milestone as XenServer moves to a full open source
model beginning with the new XenServer 6.2. Cutting right to the
chase, here are the highlights that I?ll go into more detail on:

??? XenServer 6.2 is available as a free open source virtualization
platform for all users
??? Citrix is also introducing a new XenServer.org community portal
??? Citrix provides a paid version of XenServer that includes
support and maintenance
??? New CPU socket licensing
??? New simplified packaging and pricing


http://blogs.citrix.com/2013/06/25/xenserver-6-2-is-now-fully-open-source/
Introducing the New XenServer.org Community

On top of all the product announcements, we?re also excited to
introduce the new XenServer.org community portal to provide source
code access as well as drive innovation and discussion around server
virtualization and cloud. To learn more about the community, what it
means to you and how to participate go check out XenServer.org. But
who better to talk about the community than Lars Kurth, the Community
Director of XenServer.org so for the full story take a look at his
blog on XenServer.org.







Links:
------
[1] http://en.wikipedia.org/wiki/Computer_software
[2] http://en.wikipedia.org/wiki/Free_software
[3] http://en.wikipedia.org/wiki/Open_source_software

[Bob Edwards]

Post by George
What are you using for an FOSS or OpenSource Hypervisor and Management
GUI,_ if you are using any_? .

For full virtualisation, I am slowly transitioning from VirtualBox (runs
on a bunch of host systems) to KVM (Linux hosts only - but that is all I
am really interested in, at the end of the day). Both have reasonable
GUI management interfaces.

For most of my virtualisation, I can easily get by with O/S level
virtualisation and I have transitioned most of the systems I look after,
or assist in looking after, from OpenVZ to Linux Containers (lxc). I
don't use GUI management interfaces for either, the commandline rules!

Hope this is helpful?

Bob Edwards.

Post by George
http://en.wikipedia.org/wiki/Free_and_open-source_software
Free and open-source software (FOSS) is computer software [1] that can
be classified as both free software [2] _and_ open source software
[3].
I am still a little confused regards the differences between Xen and
XenServer. Xen could be the community edition of XenServer which is
the propriety Citrix version which they may have also released to Open
Source while offering paid support (I found conflicting statements
regards the "open"ness of XenServer).
I am Looking for a FOSS GUI management tool for Xen that was not tied
to a commercial version was very difficult. Maybe Ganeti, OpenNebula
or OpenXenManager ?
http://wiki.xen.org/wiki/Xen_Management_Tools
https://github.com/OpenXenManager/openxenmanager
http://www.dedoimedo.com/computers/openxenmanager.html
OpenXenManager is an open-source multiplatform clone of
Citrix XenCenter. It is written in Python, using pyGTK for its
interface.
http://opennebula.org/about/contributors/
http://opennebula.org/about/project/
Since its first public release of software in March 2008, it
has evolved through open-source releases and now operates as an open
source project.
https://code.google.com/p/ganeti/
These products did not seem to match FOSS (FOSS would exclude words
like "price" and "license");
https://xen-orchestra.com/pricing.html
http://www.openqrm-enterprise.com/products/enterprise-edition/pricing-and-licensing.html
http://www.citrix.com/products/xenserver/buy.html (How to Buy
XenServer)
http://www.zentific.com/ (For questions, pre-sales...)
http://www.convirture.com/support_enterprise.php
http://www.convirture.com/support_opensource.php
====My research
notes==================================================
Open Source means that you have influence over the direction of the
code. You are not at the mercy of some immovable external organization
which may have priorities which do not align with your organization.
You can participate and help ensure that your needs are heard in the
process. And you never have to worry that some entity has decided to
terminate the product for business reasons. An Open Source project
will live as long as there are parties interested in advancing the
software.
Who Uses the Xen Project Code?
Our hypervisor has a user base in the millions, that include cloud
providers such as Amazon Web Services, Rackspace Hosting, Verizon
Cloud and many others. You may also want to check out the Directory
for vendors, products, projects, services and research related to the
Xen Project.
http://wiki.xenproject.org/wiki/Xen_Project_Beginners_Guide
http://www.openqrm-enterprise.com/resources/documentation-howtos/howtos/virtualization-with-xen-and-openqrm-51-on-debian-wheezy.html
http://sourceforge.net/projects/openqrm/files/latest/download
http://www.citrix.com/products/xenserver/overview.html
https://xen-orchestra.com/pricing.html
http://www.openqrm-enterprise.com/products/enterprise-edition/pricing-and-licensing.html
http://www.citrix.com/products/xenserver/buy.html (How to Buy
XenServer)
http://www.zentific.com/ (For questions, pre-sales...)
http://www.convirture.com/support_enterprise.php
http://www.convirture.com/support_opensource.php
http://xenserver.org/get-support.html
Citrix XenServer subscription offers customers 24x7 worldwide support,
commercial license protections and the ability to apply hotfixes via
the XenCenter user interface in a seamless and easy to understand way.
http://blogs.citrix.com/2013/06/25/xenserver-6-2-is-now-fully-open-source/
XenServer 6.2 is now fully open source!
It?s an exciting day for Citrix, our customers and the open source
community as we announce some BIG news for Citrix XenServer. Today we
cross another major milestone as XenServer moves to a full open source
model beginning with the new XenServer 6.2. Cutting right to the
XenServer 6.2 is available as a free open source virtualization
platform for all users
Citrix is also introducing a new XenServer.org community portal
Citrix provides a paid version of XenServer that includes
support and maintenance
New CPU socket licensing
New simplified packaging and pricing
http://blogs.citrix.com/2013/06/25/xenserver-6-2-is-now-fully-open-source/
Introducing the New XenServer.org Community
On top of all the product announcements, we?re also excited to
introduce the new XenServer.org community portal to provide source
code access as well as drive innovation and discussion around server
virtualization and cloud. To learn more about the community, what it
means to you and how to participate go check out XenServer.org. But
who better to talk about the community than Lars Kurth, the Community
Director of XenServer.org so for the full story take a look at his
blog on XenServer.org.
------
[1] http://en.wikipedia.org/wiki/Computer_software
[2] http://en.wikipedia.org/wiki/Free_software
[3] http://en.wikipedia.org/wiki/Open_source_software

[Michael Still]

Does this GUI need to be able to manage more than just the local machine?

OpenStack does all that stuff, but is probably overkill. On the other hand,
virt-manager has a GUI, is Open Source, and libvirt can manage Xen. So it
might meet your needs?

Michael

On Wed, Oct 1, 2014 at 9:38 AM, Bob Edwards <Robert.Edwards at anu.edu.au>

Post by Bob Edwards

Post by George
What are you using for an FOSS or OpenSource Hypervisor and Management
GUI,_ if you are using any_? .

For full virtualisation, I am slowly transitioning from VirtualBox (runs
on a bunch of host systems) to KVM (Linux hosts only - but that is all I
am really interested in, at the end of the day). Both have reasonable
GUI management interfaces.
For most of my virtualisation, I can easily get by with O/S level
virtualisation and I have transitioned most of the systems I look after,
or assist in looking after, from OpenVZ to Linux Containers (lxc). I
don't use GUI management interfaces for either, the commandline rules!
Hope this is helpful?
Bob Edwards.
http://en.wikipedia.org/wiki/Free_and_open-source_software

Post by George
Free and open-source software (FOSS) is computer software [1] that can
be classified as both free software [2] _and_ open source software
[3].
I am still a little confused regards the differences between Xen and
XenServer. Xen could be the community edition of XenServer which is
the propriety Citrix version which they may have also released to Open
Source while offering paid support (I found conflicting statements
regards the "open"ness of XenServer).
I am Looking for a FOSS GUI management tool for Xen that was not tied
to a commercial version was very difficult. Maybe Ganeti, OpenNebula
or OpenXenManager ?
http://wiki.xen.org/wiki/Xen_Management_Tools
https://github.com/OpenXenManager/openxenmanager
http://www.dedoimedo.com/computers/openxenmanager.html
OpenXenManager is an open-source multiplatform clone of
Citrix XenCenter. It is written in Python, using pyGTK for its
interface.
http://opennebula.org/about/contributors/
http://opennebula.org/about/project/
Since its first public release of software in March 2008, it
has evolved through open-source releases and now operates as an open
source project.
https://code.google.com/p/ganeti/
These products did not seem to match FOSS (FOSS would exclude words
like "price" and "license");
https://xen-orchestra.com/pricing.html
http://www.openqrm-enterprise.com/products/enterprise-
edition/pricing-and-licensing.html
http://www.citrix.com/products/xenserver/buy.html (How to Buy
XenServer)
http://www.zentific.com/ (For questions, pre-sales...)
http://www.convirture.com/support_enterprise.php
http://www.convirture.com/support_opensource.php
====My research
notes==================================================
Open Source means that you have influence over the direction of the
code. You are not at the mercy of some immovable external organization
which may have priorities which do not align with your organization.
You can participate and help ensure that your needs are heard in the
process. And you never have to worry that some entity has decided to
terminate the product for business reasons. An Open Source project
will live as long as there are parties interested in advancing the
software.
Who Uses the Xen Project Code?
Our hypervisor has a user base in the millions, that include cloud
providers such as Amazon Web Services, Rackspace Hosting, Verizon
Cloud and many others. You may also want to check out the Directory
for vendors, products, projects, services and research related to the
Xen Project.
http://wiki.xenproject.org/wiki/Xen_Project_Beginners_Guide
http://www.openqrm-enterprise.com/resources/documentation-
howtos/howtos/virtualization-with-xen-and-openqrm-51-on-
debian-wheezy.html
http://sourceforge.net/projects/openqrm/files/latest/download
http://www.citrix.com/products/xenserver/overview.html
https://xen-orchestra.com/pricing.html
http://www.openqrm-enterprise.com/products/enterprise-
edition/pricing-and-licensing.html
http://www.citrix.com/products/xenserver/buy.html (How to Buy
XenServer)
http://www.zentific.com/ (For questions, pre-sales...)
http://www.convirture.com/support_enterprise.php
http://www.convirture.com/support_opensource.php
http://xenserver.org/get-support.html
Citrix XenServer subscription offers customers 24x7 worldwide support,
commercial license protections and the ability to apply hotfixes via
the XenCenter user interface in a seamless and easy to understand way.
http://blogs.citrix.com/2013/06/25/xenserver-6-2-is-now-
fully-open-source/
XenServer 6.2 is now fully open source!
It?s an exciting day for Citrix, our customers and the open source
community as we announce some BIG news for Citrix XenServer. Today we
cross another major milestone as XenServer moves to a full open source
model beginning with the new XenServer 6.2. Cutting right to the
XenServer 6.2 is available as a free open source virtualization
platform for all users
Citrix is also introducing a new XenServer.org community portal
Citrix provides a paid version of XenServer that includes
support and maintenance
New CPU socket licensing
New simplified packaging and pricing
http://blogs.citrix.com/2013/06/25/xenserver-6-2-is-now-
fully-open-source/
Introducing the New XenServer.org Community
On top of all the product announcements, we?re also excited to
introduce the new XenServer.org community portal to provide source
code access as well as drive innovation and discussion around server
virtualization and cloud. To learn more about the community, what it
means to you and how to participate go check out XenServer.org. But
who better to talk about the community than Lars Kurth, the Community
Director of XenServer.org so for the full story take a look at his
blog on XenServer.org.
------
[1] http://en.wikipedia.org/wiki/Computer_software
[2] http://en.wikipedia.org/wiki/Free_software
[3] http://en.wikipedia.org/wiki/Open_source_software

--
linux mailing list
linux at lists.samba.org
https://lists.samba.org/mailman/listinfo/linux

[Stephen Gibson]

My 20 year old son is looking for summer employment/internships,
however, he does not know who he might contact in Canberra.

James is studying at UNSW, 2nd year engineering, with a significant
computing component, giving him a background in C, Java, Perl, Python,
Linux,
and other stuff, that he would be happy to fill you in on.

Any suggestions for suitable contact Companies/persons?

Thanks,

Steve.

[Bryan Kilgallin]

Press, confirmed by a union delegate, is awash with news of tech
retrenchment here. Suggest elsewhere.

[Andrew Donnellan]

I've heard that Orion Health is looking for interns, applications 29
Sep-17 Oct: http://www.orionhealth.com/careers. Not particularly
Linux-focused as far as I'm aware, mostly Java/web development. I have
heard good things about them.


Andrew

Post by Stephen Gibson
My 20 year old son is looking for summer employment/internships,
however, he does not know who he might contact in Canberra.
James is studying at UNSW, 2nd year engineering, with a significant
computing component, giving him a background in C, Java, Perl, Python,
Linux,
and other stuff, that he would be happy to fill you in on.
Any suggestions for suitable contact Companies/persons?
Thanks,
Steve.

--
Andrew Donnellan
Director
DigiACTive Pty Ltd (ABN 62 166 886 871)


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[Mike Carden]

On Wed, Oct 1, 2014 at 11:08 AM, Stephen Gibson

My 20 year old son is looking for summer employment/internships, however, he
does not know who he might contact in Canberra.

One tricky thing in Canberra is that quite a lot of IT work needs a
security clearance.

The hard part is that to get one you need a sponsor - normally an
employer. Your sponsor both pays the non-trivial admin cost of getting
the clearance and asserts that you need it for the work you will do.

So a prospective intern is at a disadvantage from the outset.

But not all IT work is directly for government or military.

[George]

Michael,
I did try OpenStack, but never quite got the hang of installing it.
Tried oVirt (very nice) but it did not seem stable enough, way too
much development work and changes? happening.

Virt-Manager as it is in Debian and CentOS7 is the older version that
does not support snapshots. This is where I ran into difficulties.?
Maybe as Bob suggested, learning the command line is a solution? This
evening I may get chance to try the command line.

https://wiki.archlinux.org/index.php/libvirt#Live_snapshots
A feature called external snapshotting allows one to take a live
snapshot of a virtual machine without turning it off. Currently it
only works with qcow2 and raw file based images.

http://wiki.qemu.org/Features/Snapshots

http://cuckoo.readthedocs.org/en/latest/installation/guest/saving/
If decided to adopt KVM, you must fist of all be sure to use a disk
format for your virtual machines which supports snapshots. By default
libvirt tools create RAW virtual disks, and since we need snapshots
you?ll either have to use QCOW2 or LVM.



VM snapshots can be managed using the following commands.





$ virsh snapshot-list ?VM-Name?



$ virsh snapshot-create ""



$ virsh snapshot-revert



$ virsh snapshot-delete ?VM-Name? 1234567890






http://wiki.qemu.org/Features/Livebackup
http://vitobotta.com/kvm-lvm-virtual-machines-backup-cloning/#sthash.iUJpDIhv.dpbs


At Wednesday, 01-10-2014 on 09:44 Michael Still wrote:


Does this GUI need to be able to manage more than just the local
machine?

OpenStack does all that stuff, but is probably overkill. On the other
hand,
virt-manager has a GUI, is Open Source, and libvirt can manage Xen. So
it
might meet your needs?

Michael

[1]



Links:
------
[1] https://lists.samba..org/mailman/listinfo/linux

[George]

From the discussion so far, I may stay with KVM, Virt-Manager (not
sure if it would be a good idea (could cause stability issues) for me
to manually install later versions of virt-manager and required
dependencies?.??

The virtualisation features that I want are a short list, just
snapshots are an important item on the list, so Virt-Manager supports
most of what I want to do, and with a few command line commands, my
needs could be answered.? More experimentation and more experience
will help me learn the limitations and reliability of Linux
virtualisation.

And not sure when Debian or CentOS are likely to update to
Virt-Manager > 1.0 and thus support snapshots from GUI. So as
suggested, learning the command line for virsh may be the way to go.?


I find command lines difficult, slower to learn, I can never remember
the syntax, and I am prone to type the wrong thing, whereas using a
GUI, you can look for the feature you want to use, and then select
it.? For me, I find the GUI method of managing systems is much faster
and less prone to user error.? Keeping? scripts of commands for
specific tasks (for working on your servers), and running these
scripts when needed, is one way to minimize user typing errors. Maybe
I can write a script for each virtual machine that "takes snapshot,
installs update, validates services are still available,
removes/consolidates snapshot, or automatically roles back, and then
emails me the result" ? and then schedule this script for 2:00am each
day or week or month depending on the frequency I want updates to be
installed.

If anyone else out there is using virtualisation, I would be
interested in reading about your adventures.? Bob, Stephen if you
have any other personal experiences you are willing to share, it will
make fun reading too.

_Here is bit more of my (continuing) research;_

https://wiki.archlinux.org/index.php/libvirt#Live_snapshots
Live snapshots A feature called external snapshotting allows one to
take a live snapshot of a virtual machine without turning it off.
Currently it only works with qcow2 and raw file based images.

http://cuckoo.readthedocs.org/en/latest/installation/guest/saving/
https://nsrc.org/workshops/2014/sanog23-virtualization/raw-attachment/wiki/Agenda/ex-debian-kvm-libvirt.htm
Snaphots are supported using the qcow2 format; the disk image file
contains both the disk snapshots and the CPU/RAM state.

VM snapshots can be managed using the following commands.
$ virsh snapshot-create
$ virsh snapshot-list ?VM-Name?
$ virsh snapshot-revert
$ virsh snapshot-delete ?VM-Name? 1234567890


http://docs.fedoraproject.org/en-US/Fedora/18/html/Virtualization_Administration_Guide/chap-Virtualization_Administration_Guide-Managing_guests_with_virsh.html

This table contains virsh command options for snapshots:
Table 15.7. Snapshot options
Command ??? Description
snapshot-create? Create a snapshot.?
snapshot-current? Get the current snapshot.?
snapshot-delete? Delete a domain snapshot.?
snapshot-dumpxml? Dump XML for a domain snapshot.?
snapshot-list? List snapshots for a domain.?
snapshot-revert? Revert a domain to a snapshot.?

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization_Administration_Guide/chap-Virtualization_Administration_Guide-Managing_guests_with_virsh.html
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization_Administration_Guide/sect-snapshot-management.html


_Other sites_
http://wiki.qemu.org/Features/Snapshots
http://blog.mattbrock.co.uk/virtualisation-with-kvm-and-lvm-on-centos-6-via-the-command-line/
http://wiki.qemu.org/Features/Livebackup
http://vitobotta.com/kvm-lvm-virtual-machines-backup-cloning/#sthash.iUJpDIhv.dpbs
https://nsrc.org/workshops/2014/sanog23-virtualization/raw-attachment/wiki/Agenda/ex-debian-kvm-libvirt.htm
https://nsrc.org/workshops/2014/sanog23-virtualization/raw-attachment/wiki/Agenda/ex-debian-kvm-libvirt.htm
http://nickbeare.com/redhat.html

yum install tigervnc-server


http://kashyapc.com/2011/10/04/snapshotting-with-libvirt-for-qcow2-images/
_There are several different types of snapshots possible_. Some idea
on that:

Internal snapshot: A type of snapshot, where a single QCOW2 file will
hold both the ?saved state? and the ?delta? since that saved
point. ?Internal snapshots? are very handy because it?s only a
single file where all the snapshot info. is captured, and easy to
copy/move around the machines.

External snapshot: Here, the ?original qcow2 file? will be in a
?read-only? saved state, and the new qcow2 file(which will be
generated once snapshot is created) will be the delta for the changes.
So, all the changes will now be written to this delta file.
?External Snapshots? are useful for performing backups. Also,
external snapshot creates a qcow2 file with the original file as its
backing image, and the backing file can be /read/ in parallel with the
running qemu.

VM State: This will save the guest/domain state to a file. So, if you
take a snapshot including VM state, we can then shut off that guest
and use the freed up memory for other purposes on the host or for
other guests. Internally this calls qemu monitor?s ?savevm?
command. Note that this only takes care of VM state(and not disk
snapshot).

[Brad Hards]

Post by George
The virtualisation features that I want are a short list, just
snapshots are an important item on the list, so Virt-Manager supports
most of what I want to do, and with a few command line commands, my
needs could be answered. More experimentation and more experience
will help me learn the limitations and reliability of Linux
virtualisation.

Have you tried virtualbox? I find it a good solution for "simple"
virtualisation, such as running a test / experimental virtual machine on a
laptop. It has a fairly friendly GUI, and supports snapshots.

Brad

[Bob Edwards]

Post by George
From the discussion so far, I may stay with KVM, Virt-Manager (not
sure if it would be a good idea (could cause stability issues) for me
to manually install later versions of virt-manager and required
dependencies?.
The virtualisation features that I want are a short list, just
snapshots are an important item on the list, so Virt-Manager supports
most of what I want to do, and with a few command line commands, my
needs could be answered. More experimentation and more experience
will help me learn the limitations and reliability of Linux
virtualisation.

Of course, "snapshots", as you are wanting to use them, are just a
"convenience".

You can almost as easily just shutdown your VM when it is good, run dd
etc. into gzip to get a copy of the VM disk image, then start it back
up and go ahead and break it.

When you want the original back, just gunzip and dd the saved image
back over the broken VM filesystem and you effectively have the same
result as a snapshot...

Do it again and again, until you get bored...

Script it all up, for more convenience...

Cheers,

Bob Edwards.

Post by George
And not sure when Debian or CentOS are likely to update to
Virt-Manager > 1.0 and thus support snapshots from GUI. So as
suggested, learning the command line for virsh may be the way to go.
I find command lines difficult, slower to learn, I can never remember
the syntax, and I am prone to type the wrong thing, whereas using a
GUI, you can look for the feature you want to use, and then select
it. For me, I find the GUI method of managing systems is much faster
and less prone to user error. Keeping scripts of commands for
specific tasks (for working on your servers), and running these
scripts when needed, is one way to minimize user typing errors. Maybe
I can write a script for each virtual machine that "takes snapshot,
installs update, validates services are still available,
removes/consolidates snapshot, or automatically roles back, and then
emails me the result" ? and then schedule this script for 2:00am each
day or week or month depending on the frequency I want updates to be
installed.
If anyone else out there is using virtualisation, I would be
interested in reading about your adventures. Bob, Stephen if you
have any other personal experiences you are willing to share, it will
make fun reading too.
_Here is bit more of my (continuing) research;_
https://wiki.archlinux.org/index.php/libvirt#Live_snapshots
Live snapshots A feature called external snapshotting allows one to
take a live snapshot of a virtual machine without turning it off.
Currently it only works with qcow2 and raw file based images.
http://cuckoo.readthedocs.org/en/latest/installation/guest/saving/
https://nsrc.org/workshops/2014/sanog23-virtualization/raw-attachment/wiki/Agenda/ex-debian-kvm-libvirt.htm
Snaphots are supported using the qcow2 format; the disk image file
contains both the disk snapshots and the CPU/RAM state.
VM snapshots can be managed using the following commands.
$ virsh snapshot-create
$ virsh snapshot-list ?VM-Name?
$ virsh snapshot-revert
$ virsh snapshot-delete ?VM-Name? 1234567890
http://docs.fedoraproject.org/en-US/Fedora/18/html/Virtualization_Administration_Guide/chap-Virtualization_Administration_Guide-Managing_guests_with_virsh.html
Table 15.7. Snapshot options
Command Description
snapshot-create Create a snapshot.
snapshot-current Get the current snapshot.
snapshot-delete Delete a domain snapshot.
snapshot-dumpxml Dump XML for a domain snapshot.
snapshot-list List snapshots for a domain.
snapshot-revert Revert a domain to a snapshot.
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization_Administration_Guide/chap-Virtualization_Administration_Guide-Managing_guests_with_virsh.html
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization_Administration_Guide/sect-snapshot-management.html
_Other sites_
http://wiki.qemu.org/Features/Snapshots
http://blog.mattbrock.co.uk/virtualisation-with-kvm-and-lvm-on-centos-6-via-the-command-line/
http://wiki.qemu.org/Features/Livebackup
http://vitobotta.com/kvm-lvm-virtual-machines-backup-cloning/#sthash.iUJpDIhv.dpbs
https://nsrc.org/workshops/2014/sanog23-virtualization/raw-attachment/wiki/Agenda/ex-debian-kvm-libvirt.htm
https://nsrc.org/workshops/2014/sanog23-virtualization/raw-attachment/wiki/Agenda/ex-debian-kvm-libvirt.htm
http://nickbeare.com/redhat.html
yum install tigervnc-server
http://kashyapc.com/2011/10/04/snapshotting-with-libvirt-for-qcow2-images/
_There are several different types of snapshots possible_. Some idea
Internal snapshot: A type of snapshot, where a single QCOW2 file will
hold both the ?saved state? and the ?delta? since that saved
point. ?Internal snapshots? are very handy because it?s only a
single file where all the snapshot info. is captured, and easy to
copy/move around the machines.
External snapshot: Here, the ?original qcow2 file? will be in a
?read-only? saved state, and the new qcow2 file(which will be
generated once snapshot is created) will be the delta for the changes.
So, all the changes will now be written to this delta file.
?External Snapshots? are useful for performing backups. Also,
external snapshot creates a qcow2 file with the original file as its
backing image, and the backing file can be /read/ in parallel with the
running qemu.
VM State: This will save the guest/domain state to a file. So, if you
take a snapshot including VM state, we can then shut off that guest
and use the freed up memory for other purposes on the host or for
other guests. Internally this calls qemu monitor?s ?savevm?
command. Note that this only takes care of VM state(and not disk
snapshot).

[George]

I really hate showing my ignorance, I had to look up what dd was;
The dd command copies a file, converting [1] the format of the data in
the process, according to the operands [2] specified.

Snapshots have an advantage over "copies" of a virtual machine,
especially when that virtual machine is a data repository that is
larger than the free space (even when compressed) on the host
hypervisor. And 6TB of data takes a while to copy, dd, etc.? A
snapshot should just fork any new changes to the original image for
the life of the snapshot, consolidation is the process of merging the
snapshot changes back into the original image.? If the snapshot is
not too old, both of these tasks are usually are very quick.? At
least that is how I understand the VM snapshot process.

http://www.computerhope.com/unix/dd.htm


Create a ISO disc image [3] from the CD in the computer.


dd if=/dev/sr0 of=/home/hope/exampleCD.iso bs=2048 conv=noerror,sync

To be honest most of my VMs range from 500GB to 3TB, but could grow to
9TB quite easily, so I like to have a solution that can support into
the future.

Thank you for your comments. An old saying that I rather like is
"_there is more than one way to skin a cat_", even if I am a cat lover
who believes the best way is "not to skin a cat at all".





Of course, "snapshots", as you are wanting to use them, are just a
"convenience".

You can almost as easily just shutdown your VM when it is good, run dd
etc. into gzip to get a copy of the VM disk image, then start it back
up and go ahead and break it.

When you want the original back, just gunzip and dd the saved image
back over the broken VM filesystem and you effectively have the same
result as a snapshot...

Do it again and again, until you get bored...

Script it all up, for more convenience...

Cheers,

Bob Edwards.
ttps://lists.samba.org/mailman/listinfo/linux [4]



Links:

[Bob Edwards]

Post by George
I really hate showing my ignorance, I had to look up what dd was;
The dd command copies a file, converting [1] the format of the data in
the process, according to the operands [2] specified.
Snapshots have an advantage over "copies" of a virtual machine,
especially when that virtual machine is a data repository that is
larger than the free space (even when compressed) on the host
hypervisor. And 6TB of data takes a while to copy, dd, etc. A
snapshot should just fork any new changes to the original image for
the life of the snapshot, consolidation is the process of merging the
snapshot changes back into the original image. If the snapshot is
not too old, both of these tasks are usually are very quick. At
least that is how I understand the VM snapshot process.

That's all true.

I was thinking of just backing-up/copying the system area, not the
entire data repository, which should be backed up elsewhere. I suppose
the updates you want to apply might break the data repository, in
which case you could restore it from backup. But that would take
very many hours...

Cheers,

Bob Edwards.

Post by George
http://www.computerhope.com/unix/dd.htm
Create a ISO disc image [3] from the CD in the computer.
dd if=/dev/sr0 of=/home/hope/exampleCD.iso bs=2048 conv=noerror,sync
To be honest most of my VMs range from 500GB to 3TB, but could grow to
9TB quite easily, so I like to have a solution that can support into
the future.
Thank you for your comments. An old saying that I rather like is
"_there is more than one way to skin a cat_", even if I am a cat lover
who believes the best way is "not to skin a cat at all".
Of course, "snapshots", as you are wanting to use them, are just a
"convenience".
You can almost as easily just shutdown your VM when it is good, run dd
etc. into gzip to get a copy of the VM disk image, then start it back
up and go ahead and break it.
When you want the original back, just gunzip and dd the saved image
back over the broken VM filesystem and you effectively have the same
result as a snapshot...
Do it again and again, until you get bored...
Script it all up, for more convenience...
Cheers,
Bob Edwards.
ttps://lists.samba.org/mailman/listinfo/linux [4]
------
[1] http://www.computerhope.com/jargon/c/conversi.htm
[2] http://www.computerhope.com/jargon/o/operand.htm
[3] http://www.computerhope.com/jargon/i/isoimage.htm
[4] https://lists.samba.org/mailman/listinfo/linux

[George]

Bob,

1) Do you know how a Linux server can prepare for UPS shutdown by
stopping services and then changing the mount of the root partition to
be read only ?? This is something I have yet to find the time to
investigate but understand what should be implemented by the UPS
shutdown process.


2) With regards to your statement "I was thinking of just
backing-up/copying the system area";

With MS Windows, I would never have tried to backup just Windows
System area and hope to get the server to ever reboot again, however I
understand that this is actually possible with Linux (not that I yet
know how).

What would need to be backed up (not including /home if this is where
the data is), and can it be restored to a live system?? (I guess this
is documented somewhere in the Internet)
(my quick suggestion of what would need to be backed up? for MySQL,
DoveCot, Postfix, Samba?).
/etc
/var/
/bin
/sbin
/selinux
/proc
/lib
/lib64

Does the broken server's drive need to be mounted in another server
and then the files restored across the existing, broken server? Or if
the server is actually running, can services be stopped and the files
be restored.

??????I really hate showing my ignorance, I had to look up what

dd was;

The dd command copies a file, converting [1] the format of the data in
the process, according to the operands [2] specified.
Snapshots have an advantage over "copies" of a virtual machine,
especially when that virtual machine is a data repository that is
larger than the free space (even when compressed) on the host
hypervisor. And 6TB of data takes a while to copy, dd, etc.??A
snapshot should just fork any new changes to the original image for
the life of the snapshot, consolidation is the process of merging the
snapshot changes back into the original image.??If the snapshot is
not too old, both of these tasks are usually are very quick.??At
least that is how I understand the VM snapshot process.

That's all true.

I was thinking of just backing-up/copying the system area, not the
entire data repository, which should be backed up elsewhere. I suppose
the updates you want to apply might break the data repository, in
which case you could restore it from backup. But that would take
very many hours...

Cheers,

Bob Edwards.

http://www.computerhope.com/unix/dd.htm
Create a ISO disc image [3] from the CD in the computer.
dd if=/dev/sr0 of=/home/hope/exampleCD.iso bs=2048 conv=noerror,sync
To be honest most of my VMs range from 500GB to 3TB, but could grow to
9TB quite easily, so I like to have a solution that can support into
the future.
Thank you for your comments. An old saying that I rather like is
"_there is more than one way to skin a cat_", even if I am a cat lover
who believes the best way is "not to skin a cat at all".
?? Of course, "snapshots", as you are wanting to use them, are just

a

"convenience".
You can almost as easily just shutdown your VM when it is good, run dd
etc. into gzip to get a copy of the VM disk image, then start it back
up and go ahead and break it.
When you want the original back, just gunzip and dd the saved image
back over the broken VM filesystem and you effectively have the same
result as a snapshot...
Do it again and again, until you get bored...
Script it all up, for more convenience...
Cheers,
Bob Edwards.
ttps://lists.samba.org/mailman/listinfo/linux [4]
------
[1] http://www.computerhope.com/jargon/c/conversi.htm
[2] http://www.computerhope.com/jargon/o/operand.htm
[3] http://www.computerhope.com/jargon/i/isoimage.htm
[4] https://lists.samba.org/mailman/listinfo/linux

[Bob Edwards]

Post by George
Bob,
1) Do you know how a Linux server can prepare for UPS shutdown by
stopping services and then changing the mount of the root partition to
be read only ? This is something I have yet to find the time to
investigate but understand what should be implemented by the UPS
shutdown process.

Nope. But I'm sure it can be done...

Post by George
2) With regards to your statement "I was thinking of just
backing-up/copying the system area";
With MS Windows, I would never have tried to backup just Windows
System area and hope to get the server to ever reboot again, however I
understand that this is actually possible with Linux (not that I yet
know how).
What would need to be backed up (not including /home if this is where
the data is), and can it be restored to a live system? (I guess this
is documented somewhere in the Internet)
(my quick suggestion of what would need to be backed up for MySQL,
DoveCot, Postfix, Samba?).
/etc
/var/
/bin
/sbin
/selinux
/proc
/lib
/lib64
Does the broken server's drive need to be mounted in another server
and then the files restored across the existing, broken server? Or if
the server is actually running, can services be stopped and the files
be restored.

So, without wanting to teach you how to suck eggs, when I install
a system (VM or otherwise), I invariably (ie. always) put /home on
a separate block device (partition, LVM volume, device, etc.) from /.
In some cases /home is NFS mounted, or bind mounted inside a container.

I sometimes put /var on it's own device as well.

So, I was assuming you would have done likewise...

With everything except /home on a single device, it is easy enough
to do what I suggested in a previous post - back up the entire root
block device ("system area") as one image for testing/experimental
purposes. Not sure I would recommend restoring it on a "live" system,
but certainly you can restore when the VM is down and then start the
VM up again with the good image.

In terms of normal backups, I backup /etc (also managed with
etckeeper...), /home, /root, /usr/local and /var.

No point in backing up /proc - it is entirely dynamic. Similarly for
/dev if your distro is using udev.

If I need to rebuild, then I rebuild from scratch. Slower, but quite
rarely required. The backups of /etc and /var have all the system
settings etc., including SSH keys, passwords, packages that were
installed etc.

/bin, /sbin, /lib, /lib64 and /usr are all strictly from the distro
(usually Debian, but sometimes Ubuntu, LinuxMint, Kali etc.), so
little point in backing them up, except when experimenting.

Having said that, for my various Linux Containers, I regularly copy
each entire container from one host to another so that they are ready
to be brought up on the "other" host if their primary goes down (again,
rarely happens).

Anyway, what you are doing with VM snapshots sounds interesting - keep
us in the loop.

Bob Edwards.

Post by George

Post by George
I really hate showing my ignorance, I had to look up what

dd was;

Post by George
The dd command copies a file, converting [1] the format of the data

in

Post by George
the process, according to the operands [2] specified.
Snapshots have an advantage over "copies" of a virtual machine,
especially when that virtual machine is a data repository that is
larger than the free space (even when compressed) on the host
hypervisor. And 6TB of data takes a while to copy, dd, etc. A
snapshot should just fork any new changes to the original image for
the life of the snapshot, consolidation is the process of merging

the

Post by George
snapshot changes back into the original image. If the snapshot is
not too old, both of these tasks are usually are very quick. At
least that is how I understand the VM snapshot process.

That's all true.
I was thinking of just backing-up/copying the system area, not the
entire data repository, which should be backed up elsewhere. I suppose
the updates you want to apply might break the data repository, in
which case you could restore it from backup. But that would take
very many hours...
Cheers,
Bob Edwards.

Post by George
http://www.computerhope.com/unix/dd.htm
Create a ISO disc image [3] from the CD in the computer.
dd if=/dev/sr0 of=/home/hope/exampleCD.iso bs=2048 conv=noerror,sync
To be honest most of my VMs range from 500GB to 3TB, but could grow

to

Post by George
9TB quite easily, so I like to have a solution that can support into
the future.
Thank you for your comments. An old saying that I rather like is
"_there is more than one way to skin a cat_", even if I am a cat

lover

Post by George
who believes the best way is "not to skin a cat at all".
Of course, "snapshots", as you are wanting to use them, are just

a

Post by George
"convenience".
You can almost as easily just shutdown your VM when it is good, run

dd

Post by George
etc. into gzip to get a copy of the VM disk image, then start it

back

Post by George
up and go ahead and break it.
When you want the original back, just gunzip and dd the saved image
back over the broken VM filesystem and you effectively have the same
result as a snapshot...
Do it again and again, until you get bored...
Script it all up, for more convenience...
Cheers,
Bob Edwards.
ttps://lists.samba.org/mailman/listinfo/linux [4]
------
[1] http://www.computerhope.com/jargon/c/conversi.htm
[2] http://www.computerhope.com/jargon/o/operand.htm
[3] http://www.computerhope.com/jargon/i/isoimage.htm
[4] https://lists.samba.org/mailman/listinfo/linux

[George]

I completely forgot, Some other OS had its "event" day this
morning, I read that its version naming is going binary and so will be
called "one zero".

[George]

Hi,

When creating a Linux virtual machine, these are a few modifications
that I do, believing that they will help with performance.

Please let me know if you agree or disagree with these changes (and
why), and if you have any other changes you like to do.? I do not
believe these are essential or necessarily, or, all required, they are
just how I like to build VMs.

Install Debian with ssh, static IP address, and with or without GUI
(whether headless or with GUI, is your preference). There are times
when I will use XFCE as a GUI because it adds very little overhead to
resources while allowing for testing/working with the VM when it is
network-isolated by itself.

nano /etc/apt/sources.list
Add contrib non-free to all three repositories

apt-get update
apt-get install xinetd ntp ssh rsync fail2ban build-essential
linux-headers-$(uname -r)

/etc/ntp.conf
server 0.au.pool.ntp.org
server 1.au.pool.ntp.org
server 2.au.pool.ntp.org
server 3.au.pool.ntp.org

ntpq -p
/etc/init.d/ntp restart
# Test NTP using
ntpq -p


?
Add to the hosts file the FQDN and IP addresses of any servers that
this server will need to communication with.
nano /etc/hosts

/etc/inittab
Check that the runlevel in /etc/inittab? is set to 3 or less, e.g.
?id:2:initdefault? which stops the kernel from running a number of
high level services that are not required (e.g. X Windows). If you
installed your Debian server as a ?headless? installation, that is
without X Windows you should find that the setting is # The default
runlevel.
id:2:initdefault

nano /etc/inittab

/etc/default/grub
Add ?evelator=noop? to the GRUB_CMDLINE_LINUX_DEFAULT option so
that the kernel does not bother to optimise disk I/O, as the ESXi host
will be performing I/O optimisation.
nano /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet elevator=noop"
update-grub

Add ?noatime? to the mounting of any virtual hard disks, which
stops operations to update the last accessed time for file reads. Does
not stop create/modify time recording.? This can noticeably reduce
file I/O.?
nano /etc/fstab
# / was on /dev/sda1 during installation
UUID=28b66904-22b9-4709-81fc-ca86d80e8992
/?????????????? ext3??? errors=remount-ro,noatime
0?????? 1

Disable the reporting of RAID array status (since this Debian VM
server is not using RAID).
# /etc/init.d/mpt-statusd stop
# echo RUNDAEMON=no > /etc/default/mpt-statusd
# apt-get remove mpt-status

[Carlo Hamalainen]

Post by George
The virtualisation features that I want are a short list, just
snapshots are an important item on the list, so Virt-Manager supports
most of what I want to do, and with a few command line commands, my
needs could be answered. More experimentation and more experience
will help me learn the limitations and reliability of Linux
virtualisation.

Regarding snapshots, Docker gives you a version control style of
workflow where you can commit changes in a running container and it only
stores the diff:

https://docs.docker.com/articles/basics/#committing-saving-a-container-state

# Commit your container to a new named image
$ sudo docker commit <container_id> <some_name>

# List your containers
$ sudo docker images

Storing diffs instead of entire snapshots saves a lot of room and has
made working on an SSD laptop feasible for me.

--
Carlo Hamalainen
http://carlo-hamalainen.net

[George]

Bob,

https://wiki.archlinux.org/index.php/libvirt#Live_snapshots

Maybe I should learn how to use the command like and get over GUI's
?????? ; )



I don't use GUI management interfaces for either, the commandline
rules!

[1]



Links:
------
[1] https://lists.samba.org/mailman/listinfo/linux

[Bob Edwards]

Post by George
I was using KVM with Virt-Manager under Centos 7 and Debian Wheezy and
when I went to take a snapshot of a 6 TB server before applying
updates, and found that there was no snapshot support. For me
snapshots are a base requirement for any virtual machine. For example,
before applying any updates to a virtual server, take snapshot,
install updates, test running software to see nothing as broken,
delete snapshot while consoldiating image, or if the changes cause
issues, roll back the image to the snapshot and live without the
updates until you can apply them without causing issues.
Searching on the Internet I discovered that Virt-Manager >= version
1.0 can take snapshots if the image is qcow2.
http://blog.wikichoon.com/2014/03/snapshot-support-in-virt-manager.html
The biggest feature we added in virt-manager 1.0 is VM snapshot
support. ... Only works with qcow2 disk images. ... While the overlay
files have to be qcow2, these snapshots will work with any base disk
image. They can also be performed with very little VM downtime, at
least under a second.
When checking both Debian Jessie and CentOS 7, I discovered that
Virt-Manager was < version 1.0, so using standard packages was not
going to be a useful solution. I will be pleased with these OSs
upgrade to a virt-manager that can support snapshots,but it could be a
long while away.
Going to the Virt-Manager home page, I downloaded the latest verison
of the source code, "virt-manager 1.1.0 Sunday September 07, 2014",
http://virt-manager.org/download/
"To build an RPM, you can run: python setup.py rpm"
When I attempted to compile an RPM for CentOS 7, the compile failed
with "Requires: libosinfo >= 0.2.10".
ftp://ftp.isu.edu.tw/pub/Linux/Fedora/linux/releases/test/21-Alpha/Workstation/x86_64/os/Packages/l/libosinfo-0.2.11-1.fc21.x86_64.rpm
http://pkgs.org/fedora-21/fedora-x86_64/libosinfo-0.2.11-2.fc21.x86_64.rpm.html
http://dl.fedoraproject.org/pub/fedora/linux/development/21/x86_64/os/Packages/l/libosinfo-0.2.11-2.fc21.x86_64.rpm
The above provided an RPM for libosinfo which allowed Virt-Manager to
compile.
Now I if I create a qcow2 based virtual machine, I can take snapshots,
though I have not yet had time to test the stability or effectiveness
of these snapshots.
I would be interested in peoples comments on the above.
I originaly dismissed Xen as I believed it was tied to a commercial
company, and not completely open to the Open Source community. If I
am wrong please correct me. Also let me know what type of management
interface Xen can use.
http://en.wikipedia.org/wiki/Xen
The Xen community develops and maintains Xen as free and open-source
software, subject to the requirements of the GNU General Public
License (GPL), version 2.

As I understand it, there is nothing sinister about Xen. What is
significant is that the Xen kernel module never made it into the
Torvalds (official) kernel, whereas KVM did. So, KVM now exists
in all Linux kernels, whereas Xen needs external kernel modules to
be loaded etc. for it to work.

As for CoW, I think several work-arounds are:
- use btrfs - has snapshots etc. already
- use LVM - similarly has snapshots

(note, I haven't actually done this with KVM yet - still getting
there...)

VirtualBox is also GPL and does have snapshots and a decent management
interface etc. Again, has its own kernel module to load, but does have
the (possible) advantage that it runs on other platforms (Mac OS X and
that other one). Probably "heavier-weight" than Xen or KVM in terms of
host resources.

Bob Edwards.

[George]

So far I have always created VMs and servers with all files in
the one partition. I have not understood any usefulness for having
separate partitions. My main concern is that I do not know how large
to make the partitions and fear they will fill up as updates are
installed. Some operating systems are like that.? I have one
application that wants to install itself to /usr/share and thus takes
up space I would not have necessarily provided for.? From my limited
understanding, it is /var/log and in particularly /home that are known
to grow large, where as I would expect the other directories (what
should I call them?) like /etc /bin /sbin, etc will only increase
slightly, if at all. I guess partitioning would be a topic of its own.



$ virsh snapshot-list
http://wiki.libvirt.org/page/VM_lifecycle

As for FOSS Hypervisor and Management GUI, my efforts for installing
Virt-Manager 1.1 seemed to have not completely succeeded. When
attempting to use my installation of Virt-Manager 1.1 I found that
there was no Connect/Disconnect for the CDROM, thus I could not add or
remove CD/DVDs or ISOs of CD/DVDs.? In the end I uninstalled and
reinstall Virt-Manager 0.10 which then left me with no GUI for
managing snapshots.

I have yet to try restoring from snapshots or consolidating snapshots,
however I have now used the command line to take snapshots (took a
while for the first snapshot to be taken).? I tried to take a
snapshot of a powered down raw image but of course it would not do
this, the image has to be Qcow2. I also took a live snapshot and a
snapshot of the VM when it was shutdown.

It would be nice if I could give snapshots meaningful names and/or a
description as the number for the snapshot has little meaning unless
you record this somewhere. Various doco suggests "virsh
snapshot-create-as myvm snapshot1 "snapshot1 description" --disk-only
--atomic", but then says "The commands are not fully implemented in
libvirt yet" ?

See commands below;


http://virt-tools.org/learning/start-list-with-command-line/


[ovnode01]$ virsh -r -c qemu:///system list --all
?Id??? Name??????????????????????????
State
----------------------------------------------------
?15??? mc54??????????????????????????
running
?-???? MC43??????????????????????????
shut off
?-???? mc44??????????????????????????
shut off
?-???? Minecraft1???????????????????? shut
off
?-???? Minecraft2???????????????????? shut
off
?-???? Win8Ent01????????????????????? shut
off





[root at ovnode01 RPMS]# virsh list --all
?Id??? Name??????????????????????????
State
----------------------------------------------------
?12??? mc54??????????????????????????
running
?-???? MC43??????????????????????????
shut off
?-???? mc44??????????????????????????
shut off
?-???? Minecraft1???????????????????? shut
off
?-???? Minecraft2???????????????????? shut
off
?-???? Win8Ent01????????????????????? shut
off

[root at ovnode01 RPMS]# virsh snapshot-list mc54
?Name???????????????? Creation
Time???????????? State
------------------------------------------------------------

[root at ovnode01 RPMS]# virsh snapshot-create mc54
Domain snapshot 1412165432 created

[root at ovnode01 RPMS]# find / -name mc54

/var/lib/libvirt/qemu/snapshot/mc54

[root at ovnode01 RPMS]# find / -name mc54*.*
/etc/libvirt/qemu/mc54.xml
/var/lib/libvirt/images/mc54.img
/var/lib/libvirt/qemu/mc54.monitor
/var/log/libvirt/qemu/mc54.log

[root at ovnode01 RPMS]# ls -al /var/lib/libvirt/qemu/snapshot/
total 4
drwxr-xr-x. 3 qemu qemu?? 25 Oct? 1 22:12 .
drwxr-x---. 6 qemu qemu 4096 Oct? 1 22:01 ..
drwxr-xr-x. 2 root root?? 35 Oct? 1 22:12 mc54
[root at ovnode01 RPMS]# ls -al /var/lib/libvirt/qemu/snapshot/mc54/
total 4
drwxr-xr-x. 2 root root?? 35 Oct? 1 22:12 .
drwxr-xr-x. 3 qemu qemu?? 25 Oct? 1 22:12 ..
-rw-------. 1 root root 3438 Oct? 1 22:12 1412165432.xml

After insalling debian and shutting down.


[root at ovnode01 RPMS]# virsh snapshot-create mc54
Domain snapshot 1412166524 created

[root at ovnode01 RPMS]# virsh snapshot-list mc54
?Name???????????????? Creation
Time???????????? State
------------------------------------------------------------
?1412165432?????????? 2014-10-01 22:10:32 +1000 running
?1412166524?????????? 2014-10-01 22:28:44 +1000 shutoff


[root at ovnode01 RPMS]# ls -al /var/lib/libvirt/qemu/snapshot/mc54/
total 8
drwxr-xr-x. 2 root root?? 60 Oct? 1 22:28 .
drwxr-xr-x. 3 qemu qemu?? 25 Oct? 1 22:12 ..
-rw-------. 1 root root 3438 Oct? 1 22:28 1412165432.xml
-rw-------. 1 root root 3246 Oct? 1 22:28 1412166524.xml

[root at ovnode01 RPMS]# virsh snapshot-create mc44
error: unsupported configuration: internal snapshot for disk vda
unsupported for storage type raw


_Other notes_


http://ebalaskas.gr/wiki/kvm/libvirt

https://kashyapc.fedorapeople.org/virt/snapshots-notes/snapshots-with-virsh-for-qcow2.txt

2/ If you have a RAW disk image, convert your RAW image to qcow2 (with
preallocation) (NOTE: RAW format doesn't support snapshotting yet)
############## $ qemu-img convert -f raw -O qcow2 -o
preallocation=metadata /var/lib/libvirt/images/cs81test.img
/var/lib/libvirt/images/cs81test.qcow2
https://xdev.me/article/How_to_use_KVM_snapshots

http://ealkl.wordpress.com/2012/11/03/nw-proj-creating-snapshot-with-libvirt-kvm-qemu-continued/
On my quest for creating and reverting to snapshots created through
libvirt for KVM/qemu, I ended up trying to create disk-snapshot. These
are not very well supported ? delete and revert of disk-snapshots
seems to unsupported through libvirt in its current version, also
disk-snapshots are not designed to store the virtual machines running
state. So these weren?t too interesting, other than the fact that I
can?t seem to loose an initial disk-snapshot that I?ve created.
This is on Ubuntu 12.10, libvirt version 0.9.5.
# The snapshot-create requires a predefined XML in place, with a name
and a description.
# In this example it is assumed there is a file called template in
your working directory.
virsh snapshot-create [domain] template.xml
?
# Here we parse the name and description of the snapshot through
commandline arguments:
virsh snapshot-create-as [domain] ["some name"] ["some description"]
?
# Revert to snapshot:
virsh snapshot-revert [domain] ["snapshot name"]
?
# Reverting to snapshot, you can list the available snapshot for a
given domain by running the following command:
virsh snapshot-list [domain] --tree
?
# Creating and reverting to a snapshot will pause your VM for the
duration. So be cautious.

===================================================================
https://github.com/autotest/virt-test/issues/152

$ virsh help snapshot-create
NAME
snapshot-create - Create a snapshot from XML



SYNOPSIS
snapshot-create [] [--redefine] [--current] [--no-metadata] [--halt]
[--disk-only] [--reuse-external] [--quiesce] [--atomic] [--live]



DESCRIPTION
Create a snapshot (disk and RAM) from XML



OPTIONS
[--domain] domain name, id or uuid
[--xmlfile] domain snapshot XML
--redefine redefine metadata for existing snapshot
--current with redefine, set current snapshot
--no-metadata take snapshot but create no metadata
--halt halt domain after snapshot is created
--disk-only capture disk state but not vm state
--reuse-external reuse any existing external files
--quiesce quiesce guest's file systems
--atomic require atomic operation
--live take a live snapshot







https://blog.gluster.org/category/virsh-snapshots/

[Sam Couter]

I use LVM when partitioning virtual or physical servers so I can grow them
on demand. Or even shrink them on occasion.

Partitioning is definitely a subject all of its own. You will find plenty
of proponents of the "one big disk" approach you have taken. It's easily
the simplest approach. If it works for you, stick with it.

Post by George
So far I have always created VMs and servers with all files in
the one partition. I have not understood any usefulness for having
separate partitions. My main concern is that I do not know how large
to make the partitions and fear they will fill up as updates are
installed. Some operating systems are like that. I have one
application that wants to install itself to /usr/share and thus takes
up space I would not have necessarily provided for. From my limited
understanding, it is /var/log and in particularly /home that are known
to grow large, where as I would expect the other directories (what
should I call them?) like /etc /bin /sbin, etc will only increase
slightly, if at all. I guess partitioning would be a topic of its own.
$ virsh snapshot-list
http://wiki.libvirt.org/page/VM_lifecycle
As for FOSS Hypervisor and Management GUI, my efforts for installing
Virt-Manager 1.1 seemed to have not completely succeeded. When
attempting to use my installation of Virt-Manager 1.1 I found that
there was no Connect/Disconnect for the CDROM, thus I could not add or
remove CD/DVDs or ISOs of CD/DVDs. In the end I uninstalled and
reinstall Virt-Manager 0.10 which then left me with no GUI for
managing snapshots.
I have yet to try restoring from snapshots or consolidating snapshots,
however I have now used the command line to take snapshots (took a
while for the first snapshot to be taken). I tried to take a
snapshot of a powered down raw image but of course it would not do
this, the image has to be Qcow2. I also took a live snapshot and a
snapshot of the VM when it was shutdown.
It would be nice if I could give snapshots meaningful names and/or a
description as the number for the snapshot has little meaning unless
you record this somewhere. Various doco suggests "virsh
snapshot-create-as myvm snapshot1 "snapshot1 description" --disk-only
--atomic", but then says "The commands are not fully implemented in
libvirt yet" ?
See commands below;
http://virt-tools.org/learning/start-list-with-command-line/
[ovnode01]$ virsh -r -c qemu:///system list --all
Id Name
State
----------------------------------------------------
15 mc54
running
- MC43
shut off
- mc44
shut off
- Minecraft1 shut
off
- Minecraft2 shut
off
- Win8Ent01 shut
off
[root at ovnode01 RPMS]# virsh list --all
Id Name
State
----------------------------------------------------
12 mc54
running
- MC43
shut off
- mc44
shut off
- Minecraft1 shut
off
- Minecraft2 shut
off
- Win8Ent01 shut
off
[root at ovnode01 RPMS]# virsh snapshot-list mc54
Name Creation
Time State
------------------------------------------------------------
[root at ovnode01 RPMS]# virsh snapshot-create mc54
Domain snapshot 1412165432 created
[root at ovnode01 RPMS]# find / -name mc54
/var/lib/libvirt/qemu/snapshot/mc54
[root at ovnode01 RPMS]# find / -name mc54*.*
/etc/libvirt/qemu/mc54.xml
/var/lib/libvirt/images/mc54.img
/var/lib/libvirt/qemu/mc54.monitor
/var/log/libvirt/qemu/mc54.log
[root at ovnode01 RPMS]# ls -al /var/lib/libvirt/qemu/snapshot/
total 4
drwxr-xr-x. 3 qemu qemu 25 Oct 1 22:12 .
drwxr-x---. 6 qemu qemu 4096 Oct 1 22:01 ..
drwxr-xr-x. 2 root root 35 Oct 1 22:12 mc54
[root at ovnode01 RPMS]# ls -al /var/lib/libvirt/qemu/snapshot/mc54/
total 4
drwxr-xr-x. 2 root root 35 Oct 1 22:12 .
drwxr-xr-x. 3 qemu qemu 25 Oct 1 22:12 ..
-rw-------. 1 root root 3438 Oct 1 22:12 1412165432.xml
After insalling debian and shutting down.
[root at ovnode01 RPMS]# virsh snapshot-create mc54
Domain snapshot 1412166524 created
[root at ovnode01 RPMS]# virsh snapshot-list mc54
Name Creation
Time State
------------------------------------------------------------
1412165432 2014-10-01 22:10:32 +1000 running
1412166524 2014-10-01 22:28:44 +1000 shutoff
[root at ovnode01 RPMS]# ls -al /var/lib/libvirt/qemu/snapshot/mc54/
total 8
drwxr-xr-x. 2 root root 60 Oct 1 22:28 .
drwxr-xr-x. 3 qemu qemu 25 Oct 1 22:12 ..
-rw-------. 1 root root 3438 Oct 1 22:28 1412165432.xml
-rw-------. 1 root root 3246 Oct 1 22:28 1412166524.xml
[root at ovnode01 RPMS]# virsh snapshot-create mc44
error: unsupported configuration: internal snapshot for disk vda
unsupported for storage type raw
_Other notes_
http://ebalaskas.gr/wiki/kvm/libvirt
https://kashyapc.fedorapeople.org/virt/snapshots-notes/snapshots-with-virsh-for-qcow2.txt
2/ If you have a RAW disk image, convert your RAW image to qcow2 (with
preallocation) (NOTE: RAW format doesn't support snapshotting yet)
############## $ qemu-img convert -f raw -O qcow2 -o
preallocation=metadata /var/lib/libvirt/images/cs81test.img
/var/lib/libvirt/images/cs81test.qcow2
https://xdev.me/article/How_to_use_KVM_snapshots
http://ealkl.wordpress.com/2012/11/03/nw-proj-creating-snapshot-with-libvirt-kvm-qemu-continued/
On my quest for creating and reverting to snapshots created through
libvirt for KVM/qemu, I ended up trying to create disk-snapshot. These
are not very well supported ? delete and revert of disk-snapshots
seems to unsupported through libvirt in its current version, also
disk-snapshots are not designed to store the virtual machines running
state. So these weren?t too interesting, other than the fact that I
can?t seem to loose an initial disk-snapshot that I?ve created.
This is on Ubuntu 12.10, libvirt version 0.9.5.
# The snapshot-create requires a predefined XML in place, with a name
and a description.
# In this example it is assumed there is a file called template in
your working directory.
virsh snapshot-create [domain] template.xml
# Here we parse the name and description of the snapshot through
virsh snapshot-create-as [domain] ["some name"] ["some description"]
virsh snapshot-revert [domain] ["snapshot name"]
# Reverting to snapshot, you can list the available snapshot for a
virsh snapshot-list [domain] --tree
# Creating and reverting to a snapshot will pause your VM for the
duration. So be cautious.
===================================================================
https://github.com/autotest/virt-test/issues/152
$ virsh help snapshot-create
NAME
snapshot-create - Create a snapshot from XML
SYNOPSIS
snapshot-create [] [--redefine] [--current] [--no-metadata] [--halt]
[--disk-only] [--reuse-external] [--quiesce] [--atomic] [--live]
DESCRIPTION
Create a snapshot (disk and RAM) from XML
OPTIONS
[--domain] domain name, id or uuid
[--xmlfile] domain snapshot XML
--redefine redefine metadata for existing snapshot
--current with redefine, set current snapshot
--no-metadata take snapshot but create no metadata
--halt halt domain after snapshot is created
--disk-only capture disk state but not vm state
--reuse-external reuse any existing external files
--quiesce quiesce guest's file systems
--atomic require atomic operation
--live take a live snapshot
https://blog.gluster.org/category/virsh-snapshots/
--
linux mailing list
linux at lists.samba.org
https://lists.samba.org/mailman/listinfo/linux

[George]

Sam, thanks for your comments. If I suspect that I will need more
disk space later, then I use LVM too, especially for VMs where
everything is virtual anyway.

One day I would like to learn what happens to a physical drive LVM
configuration if one of the drives die. Do you loose the lot, or
somehow only loose the data that is on the dead drive, but how does
that affect the directory listings, files, etc.? How do you know what
was lost and what was not?

As I am currently still using/trailing KVM with Virt-Manager and
command line snapshots (until CentOS or Debian have packages for
Virt-Manager versions that support snapshots) for my virtualisation
host, last night I investigated Windows 10 as a VM on KVM.? This
worked surprisingly well. After installation (over the top of a
previous Win8 Enterprise trial that I used to test Windows VM on KVM)
I used RDP to access the image from a Windows 7 PC that has three
monitors. Windows 10 (via RDP) instantly had three screens,
performance was quite good. I could not watch full screen video from
youtube on a 24" monitor but watching video in its original screen
size worked very well, including sound.

Soon I will get back to testing command line snapshots further.

If you are using Virtualisation or containers, what Guest OS's or
processes and purpose do you use virtualisation for.? File,
Minecraft, Mail, video conferencing, and web server are the tasks that
my servers perform.



At Thursday, 02-10-2014 on 21:00 Sam Couter wrote:


I use LVM when partitioning virtual or physical servers so I can grow
them on demand. Or even shrink them on occasion.


Partitioning is definitely a subject all of its own. You will find
plenty of proponents of the "one big disk" approach you have taken.
It's easily the simplest approach. If it works for you, stick with it.

[Sam Couter]

I use LVM to flexibly split large disks into multiple partitions. I don't
use it to join disks, although it is capable. It multiplies your risk of
disk failure, however, as you can't count on anything working if a single
disk in an LVM partition fails.

I was running virtual servers to create a virtual DMZ to run email and web
services. Most recently was KVM, previously was UML and before that Xen.
Xen was pretty good isolation and performance-wise but not being part of
the mainline kernel means kernel updates randomly broke it. UML was fairly
short-lived. It's userspace and doesn't isolate guest processes all that
well although it is lightweight. Most happy with KVM, no complaints at all.

I have since decommissioned all my virtual servers and the DMZ so I
probably can't offer any more recent advice.

Post by George
Sam, thanks for your comments. If I suspect that I will need more
disk space later, then I use LVM too, especially for VMs where
everything is virtual anyway.
One day I would like to learn what happens to a physical drive LVM
configuration if one of the drives die. Do you loose the lot, or
somehow only loose the data that is on the dead drive, but how does
that affect the directory listings, files, etc. How do you know what
was lost and what was not?
As I am currently still using/trailing KVM with Virt-Manager and
command line snapshots (until CentOS or Debian have packages for
Virt-Manager versions that support snapshots) for my virtualisation
host, last night I investigated Windows 10 as a VM on KVM. This
worked surprisingly well. After installation (over the top of a
previous Win8 Enterprise trial that I used to test Windows VM on KVM)
I used RDP to access the image from a Windows 7 PC that has three
monitors. Windows 10 (via RDP) instantly had three screens,
performance was quite good. I could not watch full screen video from
youtube on a 24" monitor but watching video in its original screen
size worked very well, including sound.
Soon I will get back to testing command line snapshots further.
If you are using Virtualisation or containers, what Guest OS's or
processes and purpose do you use virtualisation for. File,
Minecraft, Mail, video conferencing, and web server are the tasks that
my servers perform.
I use LVM when partitioning virtual or physical servers so I can grow
them on demand. Or even shrink them on occasion.
Partitioning is definitely a subject all of its own. You will find
plenty of proponents of the "one big disk" approach you have taken.
It's easily the simplest approach. If it works for you, stick with it.
--
linux mailing list
linux at lists.samba.org
https://lists.samba.org/mailman/listinfo/linux