VM affinity

[apachler]

Is there a way to define a VM affinity like available in VMware which is described here: https://pubs.vmware.com/vsphere-4-e...rs_to_manage_resources/c_vm_vm_drs_rules.html

 

[Alessandro 123]

This is absolutely needed also by me.

 

[fabian]

no, that is not directly possible. if you have enough nodes and a high availability setup, you can define mutually exclusive restricted HA groups to ensure that VMs are never put on the same nodes.

 

[Alessandro 123]

Is this a planned feature for future versions?

 

[dietmar]

Is this a planned feature for future versions?

I would include it If someone provides a patch ...

 

[Alessandro 123]

I would include it If someone provides a patch ...

I would like to contribute but first i'm not a perl programmer thus I need more time than as usual, second I don't know where to start, do you have a 'developers' documentation ?

 

[dietmar]

do you have a 'developers' documentation ?

https://pve.proxmox.com/wiki/Developer_Documentation

 

[Alessandro 123]

Thanks.
If I have questions, should I ask here or do you have a developer mailinglist?

In example, probably VM affinity should be verified during a VM migration due to a failure (doing this allows administrator to move the VM manually ignoring the affinity), so, I think that some code could be implemented in the sub

$recover_fenced_service

inside src/PVE/HA/Manager.pm

that sub calls

select_service_node()

, there I can verify the affinity and skip some nodes.

I'm on the good way or totally out ?

 

[LnxBil]

I think you're referring to a setup where you have a primary and a secondary system like DNS or DHCP and don't want to have both VMs on one physical host, right? You're not referring to affinity in terms of logical or physical partitioning for licensing purpose.

Theoretical question:
What should be done if a VM has no "working" hosts with an affinity set, only anti-affinity. What should be done with the HA-VM?

 

[Alessandro 123]

It could be choosen from the web interface, if running on the first available or keep it powered off

A flag like "ignore anti-affinity if no hosts are available"
If set to true and the anti-affinity is rejecting all hosts, the VM would start anyway somewhere. If set to false, the VM will stay powered off