If you looked at the description
of the glideinWMS, you probably guessed that installing a
glideinWMS is a multi-step process.
While the documents presented here assume you will install each component on a different machine, there is nothing preventing you from installing all of them on fewer machines, or even on one machine only (excluding GCB).
However, it is recommended that the glidein WMS Collector and collocated glidein Factory node stay on their own node. And GCB cannot be shared neither with the glidein pool Collector nor with the scheduler for user submissions.
The minimum recommended configuration would thus be composed of 3 nodes:
If you don't need a GCB, the minimum recommended setup is composed of 2 nodes:
If you want to scale above a few 1000 glideins, it is recommended that you keep the scheduler for user submissions on a dedicated node: