Hello Bryan, your understanding is correct to my knowledge and experience. Host HA is restarting all affected VMs on a still running Host in case of a Host failure.
VM HA is restarting the VM in case the VM fails / is not running even though it should. VM HA will even (re)-start the VM in case you shutdown the VM on OS level, as according to CS the VM should be in running state. For the test case you described, shutting down a host and expecting all VMs to be restarted on a another host, you would need Host HA. I cannot stress the remark of Nux enough - you need a really stable NFS for Host HA on KVM. We learned it the hard way using Ceph with HA NFS Gateways, which, in our case, was not stable enough for Host HA resulting in all CloudStack hosts rebooting unexpectedly for example during Ceph Host reboots/updates. I am very curious about to hear about altenatives to NFS based Host HA on CCC. Best regards, Stephan > m...@swen.io hat am 11.10.2023 16:23 CEST geschrieben: > > > At the moment you need a nfs storage as nux wrote. Without it you are unable > to use host ha. > > As far as I understand you can use both ha options and host ha will start vms > on another host if a host will be unavailable. But I am not 100% sure about > this. > > Regards, > Swen > > -----Ursprüngliche Nachricht----- > Von: Bryan Tiang <bryantian...@hotmail.com> > Gesendet: Mittwoch, 11. Oktober 2023 15:48 > An: users@cloudstack.apache.org > Betreff: Re: AW: Cloudstack VM HA > > Hi Nix and Swen, > > Thanks for the input! Just curious, can VM HA and Host HA be enabled at the > same time? > > In our case, using Cloudstack + Linstor. > > And to clarify my understanding. Host HA migrates VMs to another Host if > Cloudstack detects the physical host to be unhealthy, right? That’s all? > > Regards, > Bryan > On 11 Oct 2023 at 7:48 PM +0800, m...@swen.io, wrote: > > Hi Bryan, > > > > we are testing the exact same scenario at the moment! :-) > > > > As far as I understand CS has 2 different HA. VM HA and Host HA. When > > talking about VM HA the VM needs to use an offering with ha is enabled. CS > > is now checking if the VM is running and if it is not running it will > > restart or recreate it. You can test this when destroying a vm via virsh > > destroy on KVM directly. CS will restart this VM. > > > > Host HA only works, as NUX wrote, with NFS-storage at the moment. As far as > > I know StorPool is developing a new framework so other storages can be used > > for host ha in the future. I read something on the ccc agenda. > > > > Regards, > > Swen > > > > -----Ursprüngliche Nachricht----- > > Von: Bryan Tiang <bryantian...@hotmail.com> > > Gesendet: Dienstag, 10. Oktober 2023 12:36 > > An: users@cloudstack.apache.org > > Betreff: Cloudstack VM HA > > > > Hi All, > > > > We are setting up Cloudstack + Linbit SDS (via plugin). Hypervisor is > > Ubuntu. > > > > We are trying to test the VM HA by powering down a physical node at random. > > However, the VMs doesn’t seem to be failing over to the other nodes. > > > > VM HA is enabled already, is there something we are missing? > > > > Regards, > > Bryan > > > >
