<![CDATA[load-balancer : Affinity to Host groups]]>Re: Using tags or custom fields for VM placement

Did this feature ever make it into the roadmap for Xen Orchestra? Specifically, the ability to create load-balancing plans that will keep specific tagged VMs running on specific tagged Hosts?

My employer is evaluating alternatives to replace our VMware environment, and the lack of this feature would put XCP-ng out of contention.

As an explanation, our cluster of Hosts are made up of two models. Some hosts have CPUs with higher frequencies and fewer cores, and some hosts have CPUs with lower frequencies and more cores. We have two groups of VMs that need to be constrained to the high-frequency/low-core CPU hosts.

  • Some VMs are running single-threaded applications, and they perform poorly on the low-frequency/high-core CPU hosts
  • One VM runs license software that checks for the CPU model, and goes to an error state if it detects that the CPU model has changed. This error requires contacting the vendor to get special unlock codes to return it to a functional state.

Is there some way to do this with load-balancer that I am not seeing/understanding, or was this never added to the plugin?

]]>https://xcp-ng.org/forum/topic/12061/load-balancer-affinity-to-host-groupsRSS for NodeTue, 18 Aug 2026 05:33:22 GMTTue, 07 Apr 2026 18:18:10 GMT60<![CDATA[Reply to load-balancer : Affinity to Host groups on Thu, 23 Apr 2026 08:52:50 GMT]]>@olivierlambert In my understanding, Anti affinity tags only looks for the tags that are attached to the VM.
For example:

Datacenter 1
Host 1
VM1-1
Host 2
VM1-2

Datacenter 2
Host 3
VM2-1
Host 4
VM2-2

VM1-1 and VM1-2 should be able to migrate to Host 1 and Host 2.
VM2-1 and VM2-2 should be able to migrate to Host 3 and Host 4.

But VM1-1 and VM1-2 should never be able to migrate to Host 3 and Host 4.
VM2-1 and VM2-2 should never be able to migrate to Host 1 and Host 2.

With the current (Anti) Affinity tags, it will only look to the tags attached to the VM, so in the example it would be possible for VM1-1 to go to Host 4, if VM2-2 would be at Host 3 together with VM2-1.
But if we could tag the hosts, it would not be possible for VM1-1 and VM1-2 to be on Host 3 and Host 4

]]>https://xcp-ng.org/forum/post/104686https://xcp-ng.org/forum/post/104686Thu, 23 Apr 2026 08:52:50 GMT<![CDATA[Reply to load-balancer : Affinity to Host groups on Thu, 09 Apr 2026 12:38:34 GMT]]>Why not using anti affinity with the load balancer? This way, you can have multiple groups of VMs that won't run at the same place

]]>https://xcp-ng.org/forum/post/104299https://xcp-ng.org/forum/post/104299Thu, 09 Apr 2026 12:38:34 GMT<![CDATA[Reply to load-balancer : Affinity to Host groups on Thu, 09 Apr 2026 12:31:21 GMT]]>+1 from me as well.
We have 2 server-rooms with 2 XCP-hosts each. Host groups would allow to keep certain HA requirements fo a VM fulfilled while not pinning the VM on one host.

]]>https://xcp-ng.org/forum/post/104298https://xcp-ng.org/forum/post/104298Thu, 09 Apr 2026 12:31:21 GMT<![CDATA[Reply to load-balancer : Affinity to Host groups on Wed, 08 Apr 2026 13:45:08 GMT]]>+1 this.

We would like to run certain VM's only in certain datacenters, but allow the VM to migrate to other hosts in the same datacenter.

]]>https://xcp-ng.org/forum/post/104265https://xcp-ng.org/forum/post/104265Wed, 08 Apr 2026 13:45:08 GMT<![CDATA[Reply to load-balancer : Affinity to Host groups on Tue, 07 Apr 2026 20:26:24 GMT]]>Ping @gregoire

]]>https://xcp-ng.org/forum/post/104240https://xcp-ng.org/forum/post/104240Tue, 07 Apr 2026 20:26:24 GMT