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stormi merged 6 commits into from
May 18, 2026
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ha.md: explain how to prevent automatic reboots on HA-protected VMs #459

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doc(ha.md): explain how to prevent automatic reboots
thomas-dkmt Apr 14, 2026
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split and clarify warnings, as suggested by psafont
thomas-dkmt Apr 14, 2026
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apply changes suggested by stormi
thomas-dkmt Apr 15, 2026
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ha.md: fix instructions for vm reboot behavior
thomas-dkmt Apr 22, 2026
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Reword the explanation of the vm reboot behavior, as suggested by psa…
thomas-dkmt May 7, 2026
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ha.md: implement text fixes suggested by stormi
thomas-dkmt May 11, 2026
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22 changes: 21 additions & 1 deletion docs/management/ha.md
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Expand Up @@ -193,9 +193,13 @@ If you shut the VM down with `Xen Orchestra` or `xe`, the VM will be stopped nor

However, if you halt the VM directly in the guest OS (via the console or in SSH), XCP-ng is NOT aware of what's going on. The system will think the VM is down and will consider that an anomaly. As a result, the VM will be **started automatically!**. This behavior prevents an operator from shutting down the system and leaving the VM unavailable for a long time.

#### Configure VM shutdown behavior

##### For an entire pool

:::tip

Starting with XAPI 25.16.0, VM restart behavior can be changed. To do this, run this command:
Starting with XAPI 25.16.0, VM restart behavior can be changed on a pool-wide basis. To do this, run this command:

```
xe pool-param-set uuid=... ha-reboot-vm-on-internal-shutdown=false
Expand All @@ -204,6 +208,22 @@ As a result, VMs that are shut down internally or through the API will restart t

:::

##### For specific VMs

If you don't want a VM to reboot automatically when it has been shut down from the guest OS, adjust the VM reboot behavior with the parameter called `Pool.ha_reboot_vm_on_internal_shutdown`.
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@stormi stormi Apr 16, 2026

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That's the pool-wide setting! There's no per VM setting, all you can do is to change the ha-restart-priority.


:::warning
Applying these changes means that your VMs will stay off after they have been shut down, until you restart them yourself.
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@stormi stormi Apr 16, 2026

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This relates to the pool wide setting.

:::

- **Using the `xe` cli:** :
- To disable automatic reboots, run `xe vm-param-set uuid=<vm_uuid> ha-restart-priority=`.
- To (re-)enable automatic reboots, run `xe vm-param-set uuid=<vm_uuid> ha-restart-priority=restart` or `xe vm-param-set uuid=<vm_uuid> ha-restart-priority=best-effort`.
- **Using Xen Orchestra**:
To change the VM reboot behavior from Xen Orchestra, check out the instructions in the [Xen Orchestra documentation](https://docs.xen-orchestra.com/manage_infrastructure#vm-high-availability-ha).

Once you've changed the reboot parameter, shut the VM down. After you have started the VM again, feel free to re-enable automatic reboots.

### Host failure

We'll see 3 different scenarios for the host, with an example on 2 hosts, **lab1** and **lab2**:
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