Custom Group Calculation

[stephankuehne]

In our Setup, we have a vCenter with 4 Clusters and we need to monitor them differently. So, we created two Custom Groups:

Group 1:

Every descendant VM of Cluster1 / Cluster2 / Cluster3

Group 2:

Every descendent of vCenter
Excludes Group 1 (and its descendants)

We have noticed that if we add new VMs to Clusters 1/2/3, they appear in Group 1, but they are not automatically excluded in Group 2.

Even though this whole approach can be questioned, we have primarily two specific questions (for my understanding):

1. If we check the “Keep Group membership up to date” – how often will the group membership be calculated or are there any triggers?
2. If we exclude a whole group (with its descendants), will this be a dynamic exclusion or will the exclusion list stay static no matter whether the initially excluded group changes or not?

Thanks!

[daphnissov]

You'll definitely need to keep group membership up to date, and that usually happens upon every collection cycle. If that group has dynamic membership and you exclude it, the exclusion will effectively be dynamic as well.

[sxnxr]

Custom datacenters would be great for this

1. Create a CDC called Group 1 CDC ( or what ever name is good for you)
2. Add Clusters 1, 2 & 3 to it
3. Create a CDC called Group 2 CDC
4. Add cluster 4 to it
5. Create a custom group called Group 1
6. create membership rules based on virtual machine with decedent of is Group 1 CDC (make sure it is the CDC object)
7. Create a custom group called Group 2
8. create membership rules based on virtual machine with decedent of is Group 2 CDC (make sure it is the CDC object)

That way it is all dynamic for adding VMs. The only downside is that the CDC is a manual update if you add more clusters but hopefully that does not happen much. This is how i define all my groups for VMs, Hosts, cluster and datastores for assigning policies and works well.

[stephankuehne]

Thanks for the replies so far!

@daphnissov
“Keep Group membership up to date” is basically checked everywhere.
If exclusion rules are dynamic, I don’t understand why new VMs (matching criteria’s for Group1) are not excluded from Group2 automatically.
If I re-add Group1 to exclusion list of Group2, Membership becomes as expected.
That’s why I thought, Membership might be calculated every X minutes / hours.

@sxnxr
I don’t have time to test it today, I’ll do it next week and keep you updated.

For further understanding, goal is actually to monitor the whole vCenter except VMs in mentioned three Clusters. That’s the reason why Group2 contains the whole vC except members of Group1.

[sxnxr]

Just add all the clusters you want to to monitor to one CDC and all the clusters you dont want to to the other and assign the separate policies to the correct custom group that contains the VMs