Proxmox - Guests (VMs and Containers) - Qemu-guest-agent

The qemu-guest-agent is a helper daemon, which is installed in the guest.

It is used to exchange information between the host and guest, and to execute command in the guest.

The qemu-guest-agent is used for mainly three things:

To properly shutdown the guest, instead of relying on ACPI commands or windows policies.
To freeze the guest file system when making a backup/snapshot (on windows, use the volume shadow copy service VSS).
- If the guest agent is enabled and running, it calls guest-fsfreeze-freeze and guest-fsfreeze-thaw to improve consistency.
In the phase when the guest (VM) is resumed after pause (for example after shapshot) it immediately synchronizes its time with the hypervisor using qemu-guest-agent (as first step).

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