permissions issue with console.log in libvirt

[Jesse Andrews]

unable to get console output of an instance due to permission issues:

steps to reproduce:

1) install nova from ubuntu packages with KVM on lucid
2) run an instance
2.5) wait for launch
3) get console output

expected: console log
actual: exception is thrown

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console.log is being created with -rw------- permissions, and upon instance kvm launch, the console.log becomes owned by the libvirt-qemu user.

     os.close(os.open(basepath('console.log'), os.O_CREAT | os.O_WRONLY, 0660))

It appears that 0660 was trying to be set - but the third parameter to os.open is buffer size, not permissions

I've worked around this by changing this to:

        os.close(os.open(basepath('console.log'), os.O_CREAT))
        os.chmod(basepath('console.log'), 0660)

AND adding the nova user to the kvm group, since after instance launch the console.log becomes:

  owner: libvirt-qemu
  group: kvm

Thoughts on how we want to actually do this?

[Jesse Andrews (anotherjesse)]

the file is nova/virt/libvirt_conn.py

[Jesse Andrews (anotherjesse)]

hmm, on further investigation either I'm missing something or libvirt is forcing permissions to 0600?

[Dave Walker (davewalker)]

@anotherjesse This does indeed seem to be the case. Touching the file to generate it with what would seem to be the correct permissions is not suitable for the way libvirt currently generates the console.log. It would seem, that this would be better fixed in libvirt IMO.

[Jay Pipes (jaypipes)]

So, should we file a bug with libvirt then?

[Soren Hansen (soren)]

The third parameter to os.open is mode, not buffer size. You're mistaking it for open() (the built-in method).

This is a libvirt problem. It does this intentionally, but it's exceedingly annoying. I've just pushed a workaround for it to nova.