Automatic backup AND restore?

[DeepB]

Hello,

first of all, this is a private home environment, not some mission critical business environment.
Also I am not sure if the Backup Server subforum is the right place.

I have a Proxmox VE where I run a few MV/Containers: A docker host, a VM running my home-automation system, a fileserver and a backup solution for specific files.

I have another box that I want to use as backup.

I want the second box to boot periodicially, if first host is online take different IP and copy VM/container/data from main host.
If main host is down take role of first host and start specific VMs/containers.

Is this possible? What would be the best way to achieve that?

I do NOT want a cluster, and I do NOT want a solution where a second (or third) host is running all the time.

thanks
Daniel

 

[dcsapak]

hi,

in general, it should be possible to script this with api/linux tools
e.g. a script at startup that pings the first host and rewrites ips/etc and then restores/starts vms/ct
(see also our api docs: https://pve.proxmox.com/wiki/Proxmox_VE_API )

but the problem with such setups (not quorum based) are always the edge cases

for example, what if your second server starts while your first server is rebooting, determining the first is offline and taking its ip. then the first hosts reboot finishes and also takes that ip
(that is just an example off the top of my head, there are surely more scenarios)

now your vms are started twice... not good

in a quorum based system, it is much harder to provoke such 'split brain' scenarios

 

[DeepB]

Ok, I can see that.

However for my use case running 3 servers is way overkill (also too expensive electricity wise).

I have no problem with 3 servers, however they should not be running all the time. Is there some kind of "cold-standby-quorum" system?

Thanks
Daniel

 

[dcsapak]

I have no problem with 3 servers, however they should not be running all the time. Is there some kind of "cold-standby-quorum" system?

what you could do is to have a qdevice as third node (e.g. a raspberry pi or something small)
see https://pve.proxmox.com/wiki/Cluster_Manager#_corosync_external_vote_support

 

[DeepB]

But if I understand that correctly the three nodes need to be running all the time?

 

[dcsapak]

But if I understand that correctly the three nodes need to be running all the time?

i meant to have your 'main node' and the qdevice running while the second node is offline, if one node is online (+qdevice) you have quorum on either node