[pve-devel] [PATCH v2 docs] qm: add guest agent section

[Stoiko Ivanov]

Thanks for getting this documented!

LGTM as it currently is! (All comments are purely suggestions - feel free
to ignore them)

One thing I would emphasize a bit more (e.g. by adding it as list items in
the initial paragraph) is that getting all the guest agent goodness needs
2 prerequisites:
* installing the agent in the guest
* enabling the communication from the hypervisor (by enabling it in the
  guest's config)

Some (minor) comments inline:
On Thu, 17 Dec 2020 13:13:35 +0100
Aaron Lauterer <a.lauterer at proxmox.com> wrote:

> Signed-off-by: Aaron Lauterer <a.lauterer at proxmox.com>
> ---
> v1 -> v2: implemented suggested changes from Dylan. Thx for that.
> 
> Additionally to the previous series [0] which changes the phrasing, it
> would be nice to have a dedicated Qemu Guest Agent section in the docs.
> 
> [0] https://lists.proxmox.com/pipermail/pve-devel/2020-December/046502.html
> 
>  qm.adoc | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 
> diff --git a/qm.adoc b/qm.adoc
> index 5e53e4a..2a2efc7 100644
> --- a/qm.adoc
> +++ b/qm.adoc
> @@ -917,6 +917,59 @@ start after those where the parameter is set. Further, this parameter can only
>  be enforced between virtual machines running on the same host, not
>  cluster-wide.
>  
> +
> +[[qm_qemu_agent]]
> +Qemu Guest Agent
> +~~~~~~~~~~~~~~~~
> +
> +The Qemu Guest Agent is a service which runs inside the VM, providing a
> +communication channel between the host and the guest. It is used to exchange
> +information and allows the host to issue commands to the guest.
> +
> +For example, the IP addresses in the VM summary panel are fetched via the guest
> +agent. When starting a backup, the guest is told via the guest agent to sync
I personally would probably separate the displaying IP-information and the
fs-freeze/thaw part into 2 paragraphs.

> +outstanding writes via the 'fs-freeze' and 'fs-thaw' commands. It is possible
> +to add custom hook scripts to react to these commands and tell software, for
When I read hook scripts in our documentation I always think first of the
various places where we allow to add custom (hook) scripts.
Not 100% sure we need to document qga-features here?

> +example a database server, to write current data to disk, so it is included in
> +the backup.
> +
> +Install Guest Agent
> +^^^^^^^^^^^^^^^^^^^
> +
> +For most Linux distributions, the guest agent is available. The package is
> +usually named `qemu-guest-agent`.
> +
> +For Windows, it can be installed from the
> +https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/stable-virtio/virtio-win.iso[Fedora
> +VirtIO driver ISO].
> +
> +Enable Guest Agent
> +^^^^^^^^^^^^^^^^^^
> +
> +The guest agent can be enabled in the VM's *Options* panel.
> +A fresh start of the VM is necessary for the changes to take effect.
maybe:
s/The guest agent can be/Communcation from PVE with the guest agent can be/
> +
> +It is possible to enable the 'Run guest-trim' option. With this enabled,
> +Proxmox VE will issue a trim command to the guest after the following
> +operations that have the potential to write out zeros to the storage:
> +
> +* moving a disk to another storage
> +* live migrating a VM to another node with local storage
> +
> +On a thin provisioned storage, this can help to free up unused space.
> +
> +Troubleshooting
> +^^^^^^^^^^^^^^^
> +
> +.VM does not shut down
> +
> +Make sure the guest agent is installed and running.
> +
> +Once the guest agent is enabled, Proxmox VE will send power commands like
> +'shutdown' via the guest agent.  These commands will be ignored if the guest
> +agent in the VM is not running.
Maybe: If the guest agent is not running/listening for commands - they
cannot get executed properly and the shutdown command will run into a
timeout.

> +
> +
>  [[qm_spice_enhancements]]
>  SPICE Enhancements
>  ~~~~~~~~~~~~~~~~~~