Bug 1738820

Starting qemu-ga with -F,which will use default hook path.
#qemu-ga -m virtio-serial -p /dev/virtio-ports/org.qemu.guest_agent.0 -F

The default path is /etc/qemu-kvm/fsfreeze-hook which does not exist in RHEL8, so fsfreeze couldn't work.
The default path is /etc/qemu-ga/fsfreeze-hook which exists and works in RHEL7.


So developer, 
would you modify the default path in RHEL8 ?

You can refer to the following bugs which are related with fsfreeze-hook.
https://bugzilla.redhat.com/show_bug.cgi?id=1210707
https://bugzilla.redhat.com/show_bug.cgi?id=1644985#c9

I don't think we support starting qemu-ga from command line with default values.

qemu-guest-agent.service & qemu-ga.sysconfig seem to correctly start qemu-ga service.

Having default values point to different locations would mean to run qemu configure again for qemu-ga.

Moving to Danilo for further discussion about packaging

QEMU has been recently split into sub-components and as a one-time operation to avoid breakage of tools, we are setting the QEMU sub-component of this BZ to "General". Please review and change the sub-component if necessary the next time you review this BZ. Thanks

I came back to this problem after a long long time.

Long story short: When qemu-ga was introduced to RHEL-8, I used the bits from qemu-guest-agent from RHEL-7 as base.
In RHEL-7, qemu-guest-agent is built as standalone package, it's built as "qemu-ga", hence the "qemu-ga" folders. They should have been replaced to qemu-kvm in RHEL-8, but I missed it, and I'm afraid now it is too late.

My proposal is this: Instead of renaming /etc/qemu-ga/ to /etc/qemu-kvm, risking users using "/etc/qemu-ga/fsfreeze-hook.d" messing up their configuration, I suggest creating a link from /etc/qemu-ga/fsfreeze-hook to /etc/qemu-kvm/fsfreeze-hook so the script can be executed.

@QA/reporter: can you please check if creating a symlink works? The following subcommand should work:
$ sudo mkdir /etc/qemu-kvm/ && sudo ln -s /etc/qemu-ga/fsfreeze-hook /etc/qemu-kvm/fsfreeze-hook

Marc-Andre: Can you spot any problem with this approach?

Also asking Mirek for his opinion as well... ^^

Looks like the system missed my request for input from Mirek...

(In reply to Danilo Cesar Lemes de Paula from comment #5)
> My proposal is this: Instead of renaming /etc/qemu-ga/ to /etc/qemu-kvm,
> risking users using "/etc/qemu-ga/fsfreeze-hook.d" messing up their
> configuration, I suggest creating a link from /etc/qemu-ga/fsfreeze-hook to
> /etc/qemu-kvm/fsfreeze-hook so the script can be executed.
> ...
> Marc-Andre: Can you spot any problem with this approach?

No, qga expects to have access(path, X_OK) and then be able to exec that path. That should work fine with a link too. Whether SElinux policy is sufficient, I can't easily tell from sesearch, but I tried making a link and the script was still run.

(In reply to Danilo Cesar Lemes de Paula from comment #5)
> I came back to this problem after a long long time.
> 
> Long story short: When qemu-ga was introduced to RHEL-8, I used the bits
> from qemu-guest-agent from RHEL-7 as base.
> In RHEL-7, qemu-guest-agent is built as standalone package, it's built as
> "qemu-ga", hence the "qemu-ga" folders. They should have been replaced to
> qemu-kvm in RHEL-8, but I missed it, and I'm afraid now it is too late.
> 
> My proposal is this: Instead of renaming /etc/qemu-ga/ to /etc/qemu-kvm,
> risking users using "/etc/qemu-ga/fsfreeze-hook.d" messing up their
> configuration, I suggest creating a link from /etc/qemu-ga/fsfreeze-hook to
> /etc/qemu-kvm/fsfreeze-hook so the script can be executed.
> 
> @QA/reporter: can you please check if creating a symlink works? The
> following subcommand should work:
> $ sudo mkdir /etc/qemu-kvm/ && sudo ln -s /etc/qemu-ga/fsfreeze-hook
> /etc/qemu-kvm/fsfreeze-hook
> 
> Marc-Andre: Can you spot any problem with this approach?


I think this is best approach to allow broken scenario without breaking
existing configurations.

Moving this to AV, then cloning to RHEL later on.

QA_ACK, please?

Reproduce with version qemu-guest-agent-5.1.0-7.module+el8.3.0+8099+dba2fe3e.x86_64

Version-Release number of selected component (if applicable):
qemu-kvm-5.1.0-7.module+el8.3.0+8099+dba2fe3e.x86_64
qemu-guest-agent-5.1.0-7.module+el8.3.0+8099+dba2fe3e.x86_64

Steps to Reproduce:
1.boot RHEL8 guest with qga installed:
2.Start qemu-ga process with '-F' option inside RHEL8 as below.
#qemu-ga -m virtio-serial -p /dev/virtio-ports/org.qemu.guest_agent.0 -F -d
3.Then send command 'guest-fsfreeze-freeze' to guest on host.

Actual result:
[root@dell-per440-06]# nc -U /tmp/qga.sock
{"execute":"guest-ping"}
{"return": {}}
{"execute":"guest-fsfreeze-freeze"}
{"error": {"class": "GenericError", "desc": "can't access fsfreeze hook '/etc/qemu-kvm/fsfreeze-hook': No such file or directory"}}

Expected results:
{"return":{}}

Verified with version qemu-guest-agent-5.1.0-8.module+el8.3.0+8141+3cd9cd43.x86_64

Version-Release number of selected component (if applicable):
qemu-kvm-5.1.0-8.module+el8.3.0+8141+3cd9cd43.x86_64
qemu-guest-agent-5.1.0-8.module+el8.3.0+8141+3cd9cd43.x86_64

Steps to verify as above:

Actual result:
[root@dell-per440-06]# nc -U /tmp/qga.sock
{"execute":"guest-ping"}
{"return": {}}
{"execute":"guest-fsfreeze-freeze"}
{"return": 2}

Expected results:
as above

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (virt:8.3 bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2020:5137