KV Host HA/instance HA with shared mountpoint

[nomisunrider]

ISSUE TYPE

• Enhancement Request

COMPONENT NAME

KV Host HA/instance HA

CLOUDSTACK VERSION

N/A

CONFIGURATION

N/A

OS / ENVIRONMENT

KVM

SUMMARY

Host HA support for shared mountpoint.

Many VMware users looking at Cloudstack have FC/iSCSI block storage devices for their VMs.
Has there been any investigation/are there any plans to add KVM HA support for shared mountpoint using clustered filesystems such as OCFS2/GFS2?

[NuxRo]

I do not think so, but for now as a workaround one could just run a small (but solid) NFS storage.
You can even keep it disabled in Cloudstack so it doesn't get used by the VMs.

Looking at /usr/share/cloudstack-common/scripts/vm/hypervisor/kvm/kvmheartbeat.sh it doesn't seem like modifying it for shared mountpoint would be too difficult.

[nomisunrider]

That workaround would be for enabling HA hosts, but would not give any HA instances, correct? As I read the documentation I understand the instances must be hosted on NFS storage, so not sure what the workaround would really achieve.

Thank you

[NuxRo]

@nomisunrider I'm a bit lost in translation, so let me try to put my ideas in order.
What do you want to achieve, VM HA on a shared mount point?

Then in order to achieve that you need to:
1 - disable Host HA if you have enabled it, perhaps even out of band control if you have it (ipmi etc)
2 - add primary storage based on NFS, it can be disabled in Cloudstack if you do not plan to use it for VMs

After you have done that, your VMs hosted on shared mountpoint should be HA, even if they are not on the NFS.

[nomisunrider]

Yes, I am looking if VM HA can be supported on a shared mount point in the event of a host failure.

Following your two steps would would result in VM HA in the event a host goes offline? The VMs would power back up on another host?

Thank you