HA Failover if a Uplink fails

[basic20]

Dear community

The environment:

- vCenter 6.7

- two ESXi 6.7 in a HA Cluster

- Network connectivity:

• Host1 (one Uplink)<-> Switch1 <-> Destination
• Host2 (one Uplink)<-> Switch2 <-> Destination

- Two VMs

- All VMs are placed on Host1

Goal: if Switch1 or the Uplink of Host1 to Switch1 fails, failover of all VMs would be happened to Host2 to restore the connectivity.

How can it be done? With HA or Fault Tolerance?

Thank you.

[depping]

If you have an HA cluster and the link fails, and it is the only link(!!), then it would be an "isolation". If you configure the HA Isolation Response to be: power off and restart VMs, then HA would automatically failover the VMs.

[depping]

Do note, you need shared storage for this to work!

[basic20]

depping​, thank you for the quick response!

I attached a picture of the environment. Besides the Upllinks for the external network there are also uplinks to the internal network. So even if Switch1 would fail, the host1 will be still able to communicate with host2 via the management network.

How can it be done in this case? By adding additional isolation addresses(VMware Knowledge Base )?

[depping · Accepted solution]

Ah, that clarifies things.

HA Communicates over the Management Network and doesn't take failures of the VM network in to account, neither does FT. So what you are asking or, does not exist today.

But why not ensure you have resiliency on a networking layer, feels like a much better path to solve this problem.

[basic20]

I am not sure, but wouldn't it be the solution if I disable "das.usedefaultisolationaddress" and set "das.isolationaddress" of a system/router in the external direction?

[depping]

Makes no difference as long the hosts can communicate via the management network they will not even check the isolation address.