Bonjour Franck!

It would be interesting to narrow down where you are reaching the limits of Openstack :

Are you running out of vCPU/RAM due to too many VMs?

Are you seeing CPU steal time due to oversubscribing the hosts?
Are the VMs oversized?

Are you running out of capacity on the network side?
Are you running out of capacity on the storage side?
Is the Openstack control plane reaching its limits?

That would be surprising considering the amount of computes you have.

At such a "small" scale, some of the Openstack overhead might be tricky to deal with.

Running Controllers + Compute + Storage on the same server typically means a "hyperconverged" setup.
I am not sure if there are community run deployments that will support it out of the box. It's typically complex to deploy/support/maintain and part of a commercial support package.

Have you looked at other virtualization platforms like Proxmox?

On Thu, Mar 7, 2024 at 9:36 AM Franck VEDEL <franck.vedel@univ-grenoble-alpes.fr> wrote:

Good morning,
I currently have an Openstack cluster made up of 3 nodes, an iscsi bay (10T), 576 G of Ram, 10T, 288vcpus.
This cluster is used by around 150 students, but is reaching its limits.
Having obtained a budget to set up a larger cluster, I am wondering about the choice of the number of nodes, their role (how many controllers, network, compute, etc.) and above all what solution for storage.
Let's imagine a budget to buy 6 servers with good capacities, is the right choice Ceph storage (with cinder and rdb?) on the Openstack cluster nodes? Do we need 3 servers for a Ceph cluster and 3 for the Openstack part (in this case I lose capacity for the "compute" part)... I don't know what the right choices are and above all, I have a little afraid of going in the wrong directions.
Could any of you guide me, or give me links to sites that could help me (and that I haven't seen).
Thanks in advance

Franck VEDEL
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