Open Stack

On Mon, Sep 20, 2021 at 11:46 AM wodel youchi <wodel.youchi at gmail.com> wrote:
>
> Hi,
>
> Is it technically possible to install openstack tripleO on 3 nodes, such that all 3 nodes play the roles of controller compute and ceph storage (hci) at the same time, with replication and HA and all?

It's technically possible for a POC (just compose a role [1]
accordingly) but it's not a recommended configuration because the
controllers use pacemaker with power fencing which you don't want
running on your OSD hosts. E.g. pacemaker could take out 1/3rd of your
OSDs and make the cluster backfill. If you're short on nodes then one
option is to use four. One as a basic KVM hypervisor to host VMs
including a virtual undercloud and three virtual controllers. Then use
three physical HCI nodes which host the VMs and OSDs.

  John

[1] https://docs.openstack.org/project-deploy-guide/tripleo-docs/latest/features/custom_roles.html