Adding guest agent for hypervisor?

[icsy7867]

I have read through several docs and I am still a bit confused on this process. Currently flatcar is running on oVirt and working great. I would like to add the ovirt guest agent to the running image. I am confused on how/when/where this can be done. Would this have to be done before the image is written to disk? Or can it be done after a successful deployment?

[tormath1]

Hi @icsy7867,

I don't know about oVirt but according to the documentation (https://www.ovirt.org/dropped/guest-agent/understanding-guest-agents-and-other-tools.html):

The oVirt Guest Agent has been deprecated in favor of QEMU Guest Agent

Flatcar ships qemu-guest-agent since release 3402 (https://www.flatcar.org/docs/latest/setup/customization/acpi/#qemu-guest-agent) and you can easily try it:

./flatcar_production_qemu.sh -- -chardev socket,path=/tmp/qga.sock,server=on,wait=off,id=qga0 -device virtio-serial -device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0
ssh flatcar
systemctl status qemu*
● qemu-guest-agent.service - QEMU Guest Agent
     Loaded: loaded (/usr/lib/systemd/system/qemu-guest-agent.service; static)
     Active: active (running) since Thu 2022-12-08 14:10:45 UTC; 10s ago
   Main PID: 814 (qemu-ga)
      Tasks: 2 (limit: 30216)
     Memory: 2.1M
        CPU: 18ms
     CGroup: /system.slice/qemu-guest-agent.service
             └─814 /usr/bin/qemu-ga

Dec 08 14:10:45 localhost systemd[1]: Started QEMU Guest Agent.

[tormath1]

Exactly, the ./flatcar_production_qemu.sh is the fastest way to try Flatcar with QEMU.

From the doc (https://www.flatcar.org/docs/latest/setup/customization/acpi/#qemu-guest-agent):

The agent service will automatically be enabled if a virtio-port with the name org.qemu.guest_agent.0 is detected.

I would assume that oVirt runs VM with such a port?

[icsy7867]

Yeah I believe so. So poking around:

It looks liek the file exists. However

systemctl status qemu*

returns nothing

[tormath1]

What's the output of cat /etc/os-release ?

[icsy7867]

What's the output of cat /etc/os-release ?

core@flatcar-master /dev/virtio-ports $ cat /etc/os-release
NAME="Flatcar Container Linux by Kinvolk"
ID=flatcar
ID_LIKE=coreos
VERSION=3374.2.0
VERSION_ID=3374.2.0
BUILD_ID=2022-11-15-1845
SYSEXT_LEVEL=1.0
PRETTY_NAME="Flatcar Container Linux by Kinvolk 3374.2.0 (Oklo)"
ANSI_COLOR="38;5;75"
HOME_URL="https://flatcar.org/"
BUG_REPORT_URL="https://issues.flatcar.org"
FLATCAR_BOARD="amd64-usr"
CPE_NAME="cpe:2.3:o:flatcar-linux:flatcar_linux:3374.2.0:*:*:*:*:*:*:*"

[tormath1]

Yeah, so as mentioned: this feature is available from release 3402, so everything < 3402 (like: 3374.2.0) won't have the qemu-guest-agent installed.
Can you try it with a beta image like this one: https://www.flatcar.org/releases#release-3417.1.0? Beta images are considered stable enough to run a few of them in your workload.

[icsy7867]

I see. I didn't realize this was only available in the beta channel. I'll give it a shot!