Apache CloudStack 4.2.1 seems to have resolved the guest VM failover issues which was present in the earlier versions. The specific tests are:
- Reboot a KVM Host in a cluster which has a HA enabled VM running
- Power off a KVM Host in a cluster which has a HA enabled VM running
In both cases, Apache CloudStack 4.2.1 did the right thing – the HA enabled VM was restarted on the next available KVM host in the cluster. The entire process took less then 5 minutes with the default global settings.
Apache CloudStack 4.2.1 with KVM hypervisor is now a viable production design. However, please do run fault tolerance test with your version of CloudStack on your environment to ensure that there have been no regression.