[ClusterLabs] Clarification on resource groups

[Eugen Block]

Hi,

I'm hoping to get some clarification on my understanding of resource  
groups [0]. It states:

> One of the most common elements of a cluster is a set of resources  
> that need to be located together, start sequentially, and stop in  
> the reverse order.

Especially the "located together" attribute confuses me.

I'll try to provide some context:
I have a couple of systemd services as clones and some multi-state  
resources such as galera and rabbitmq, running on two pacemaker nodes.  
In case of an upgrade or any kind of maintenance, I want to use the  
maintenance mode for some resources, but not all of them. For example,  
I want the virtual IP, galera and rabbitmq to be still managed while  
the rest is in maintenance mode. So currently, I would run a for loop  
on the systemd services only, putting them into maintenance. This way,  
if the network stack is updated or something, the virtual IP would be  
moved to the other node. IIUC, this is not covered by the resource  
groups, is it?

Or should I have used it when building the cluster from scratch,  
creating groups containing my systemd services as primitives? And then  
clone a group?

Is there another way of achieving that? I'd appreciate any comments!

Thanks!
Eugen

[0]  
https://clusterlabs.org/projects/pacemaker/doc/2.1/Pacemaker_Explained/singlehtml/index.html#group-resources