Can I install molly-guard on a pve node?

nrodriguez

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Nov 13, 2025
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I'd like to install molly-guard on my pve nodes to prevent accidental reboots. Can I do it and being sure it doesn't break anything?

Thank you!
 
At least once in your life, you’ll reboot the wrong system or run rm -rf /. It’s a rite of passage.

Usually, you won’t make that mistake again. Since only root can reboot the system, this package won’t prevent malicious reboots - root can always override or remove the barrier.

The package also has a high likelihood of interfering with normal PVE operations, such as generating an unexpected interactive prompt when the cluster needs to fence a node or when someone tries to reboot from the UI. Since this integration hasn’t been officially tested, you won’t get a “go ahead and install it” response.

Try it at your own risk.


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The package also has a high likelihood of interfering with normal PVE operations, such as generating an unexpected interactive prompt when the cluster needs to fence a node or when someone tries to reboot from the UI
That's what I was afraid of :(
Since this integration hasn’t been officially tested, you won’t get a “go ahead and install it” response.
Thank you!
 
Can I do it and being sure it doesn't break anything?

I do install molly-guard on all of my systems, since 15 to 20 years I guess. (Edit: actually I do not know how old that tool is...) This includes all of my PVE and PBS.

Nevertheless: ymmv...
 
Last edited:
I do install molly-guard on all of my systems, since 15 to 20 years I guess. (Edit: actually I do not know how old that tool is...) This includes all of my PVE and PBS.

Nevertheless: ymmv...
Ah do you test cluster fencing ?

Personally too and without any problem.
But molly-guard is only efficient and enabled in SSH interactive mode.
Thus it shouldn't interfere with internal Proxmox mechanisms (non interactive mode).

BUT : molly-guard is NO enabled when using WEB shell... too sad :-(
 
But molly-guard is only efficient and enabled in SSH interactive mode.
Yes. That's what it is meant to do :-)

BUT : molly-guard is NO enabled when using WEB shell... too sad :-(
Correct. I do not use that method often, so it is not relevant to me :-)

You cat set:
Code:
root@pve:~# grep ALWAYS /etc/molly-guard/rc
# ALWAYS_QUERY_HOSTNAME
ALWAYS_QUERY_HOSTNAME=true

Then it will ask for the hostname also in the Web shell! :-)

It does not affect the "Reboot" button in the Gui though, but there is the "Confirm - Yes / No" dialog.

:-)
 
You cat set:
Code:
root@pve:~# grep ALWAYS /etc/molly-guard/rc
# ALWAYS_QUERY_HOSTNAME
ALWAYS_QUERY_HOSTNAME=true

Then it will ask for the hostname also in the Web shell! :-)
Nice to know ! But I would fear to break things in Promxox (cluster fencing for exemple).
 
But I would fear to break things in Promxox (cluster fencing for exemple).

A node running HA-relevant resources fences itself, if Quorum ist lost. The reboot is "hard", triggered locally. Not by an ssh-command from another node ;-)
 
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