[clug] NFSv4 "Invalid argument"

Tessa Jensen

2014-10-16 12:21:17 UTC

Check umask settings maybe? - if it's set to default, then any new file
being created by virt-manager in the ISO directory may not have the
read-write permissions that it needs.

On Thu, Oct 16, 2014 at 9:14 PM, Scott Ferguson <

Excellent George, thanks for persevering, and especially thanks from
other with the same problem who will benefit from you posting your results.
Not an ideal situation - using the set v3 method, but it works, which is
a start.

Scott,
I have had some success with the virt-manager and NFS. The issue
seems to be two fold, a) NFS version 4 is more complex and I do not
know how to use it, b) that I was not using the correct option for
controlling the version of NFS _and_ in OpenFiler I had to set the NFS
share to no_root_squash
This site
"

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization_Administration_Guide/sect-shared-storage-nfs-migration.html
"

gave me the idea to go and look in OpenFiler to see if I could change
the NFS shares (export) options, and I discovered that I could change
between the default of root_squash to no_root_squash. (of course
no_root_squash is not as secure).

That's one way - another way is to use the anonuid and anongid options.
0=root
I don't know that has any advantages or no_root_squash or the v3 method.
NOTE: I've used the no_root_squash option on webservers (no virtual
host) to get around the www-data problem, though this is not something I
now do.
------------8<-------------->8---------------------------------

I have not resolved the a) issue, but I have the b) option: "-o
vers=3"
# mount -t nfs -o vers=3 -v
192.168.0.12:/mnt/vg2/vol1/san12_nfs_ds1/kvm-images/images
/var/lib/libvirt/images
Previously I had used the wrong syntax; "nfsvers=3"

------------8<-------------->8---------------------------------
You can chain those o(ptions),should you need to (standard mount format
e.g. -o nfsver=3,sec=krb5,etc
For testing I find the -f (fake) and -v (verbose, more v's is more
verbose) options useful
e.g.:-
$ su -c "mount -fvvvt cifs -o credentials=/home/scott/.cifs
//dev/packages /var/cache/apt/archives"
mount: fstab path: "/etc/fstab"
mount: mtab path: "/etc/mtab"
mount: lock path: "/etc/mtab~"
mount: temp path: "/etc/mtab.tmp"
mount: UID: 0
mount: eUID: 0
mount: spec: "//dev/packages"
mount: node: "/var/cache/apt/archives"
mount: types: "cifs"
mount: opts: "credentials=/home/scott/.cifs"
mount: external mount: argv[0] = "/sbin/mount.cifs"
mount: external mount: argv[1] = "//dev/packages"
mount: external mount: argv[2] = "/var/cache/apt/archives"
mount: external mount: argv[3] = "-f"
mount: external mount: argv[4] = "-v"
mount: external mount: argv[5] = "-o"
mount: external mount: argv[6] = "rw,credentials=/home/scott/.cifs"
ip=192.168.0.2,unc=\\dev\packages,user=scott,pass=********
You might use sudo instead. I don't have access to an nfs share from
where I'm writing - but the effect is the same with nfs. Note that the
share isn't actually mounted (-f switch). Confusingly dev (development),
in this instance, is a box name, not a file system.

Now mounting the NFS share with option "-o vers=3" I can change the
permissions on the folders and files, see the below commands which
should explain things for you;

------------8<-------------->8--------------------------------->
=====================================================================================

Now to put the permissons the way I wanted them
--------------------------------------------------
# chown -R libvirt-qemu:libvirt-qemu /var/lib/libvirt/images
# ls -al /var/lib/libvirt/images

------------8<-------------->8--------------------------------->

And now the VM will run without an errors.

===================================================================================

But I get the below error messages when using virt-manager if I do not
use "# chmod -R 777 /var/lib/libvirt/images"
"The emulator may not have search permissions for the path
'/var/lib/libvirt/images/ISO/debian-7.5.0-amd64-DVD-1.iso'."

Hmmmm. I probably shouldn't suggest this, but an insecure solution,
might be to modify the group's membership. I'd still try the anonid/gid
options first - then that share should mount as root.
Can any other readers suggest something?
------------8<-------------->8---------------------------------
Kind regards
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