Hostisolierung

[RoBo48]

Hello,

I am currently learning more about VMware and need some advice.

I have the following configuration:
VMware Cluster with two hosts (ESXi1, ESXi2, ESXi3):

ESXi1: TestVM1 -> VLAN200 -> switch VLAN 200

ESXi2: no virtual machine -> no VLAN

ESXi3: no virtual machine -> switch VLAN 200

For example, if I want to migrate TestVM1 to ESXi2 due to a failure, it should be checked whether VLAN 200 is also available on the switch (Cisco), if not it should be migrated to a host such as ESXi3 where VLAN is configured on the external switch.

Can you give me a tip on how I can implement this?

I have found the point host Isolation under the vSphere Availability, but it is not quite clear to me how this looks in practice and whether I am correct?

I am grateful for any feedback.

[depping]

A couple of things:

1. HA does not "migrate" a VM, it restarts the VM when the host is impacted by a failure of some kind

2. If the Network Portgroup is not available on Host 2, then HA will restart the VM on Host 3, if that host has sufficient resources to restart the VM

3. Number 2 is assuming you created a portgroup on host 1 and host 3 with VLAN 200, and that portgroup is not available on Host 2.

I hope that helps. Do note, that normally customers would create the same portgroup on every host in the cluster, and have the same VLANs exposed to those hosts in that cluster. This will provide the most flexibility and highest level of availability.

if you want to know the ins and outs of HA you can find my book here:

https://www.rubrik.com/en/resources/white-papers/19/clustering-deep-dive-ebook

[RoBo48]

First of all, I would like to thank you for the quick and competent feedback!

I am interested in catching the error case if an external switch is not configured correctly and a VLAN is missing.

1. yes, but I can migrate a vm with vMotion

2. and 3. the port group are the same on every host in the cluster but not on the external switches

I think this will help to solve a problem like this:

https://kb.vmware.com/s/article/1030320

[depping]

No, the host isolation you refer to is when you have a fully correctly configured system, and then something fails or breaks and the network on which the HA traffic is running is impacted. In that case, when isolation response is configured, HA will restart the impacted workloads on a host which has a healthy network.

KEEP IN MIND, if the VM network for instance fails, and this is a different VLAN then what HA is using, then nothing will happen. HA does not have any logic to deal with that failure scenario.

Also, vMotion has nothing to do with HA... And vMotion will not check the VLAN configuration on the switch, neither will HA.