Prevent co-locating charms that may be conflicting with each other

[Ponnuvel Palaniyappan]

Charms such as ceph-mon, ceph-osd, ceph-fs, kubernetes-control-plane, etc can interfere with each other if they're deployed on the same host. While this isn't a supported configuration, charms don't prevent from anyone deploying it and then end up with issues.

Can the charm be updated to refuse deployment if one of the other charms is already deployed or being deployed?

Peter Matulis is looking at updating the documentation.

[George Kraft (cynerva)]

I guess we could include some kind of deny list for this. Such a list would never be complete, of course, but we could raise warnings for the ones we know about.

Units would need to look for other units in /var/lib/juju/agents and inspect their metadata.yaml to get the charm name to check against the deny list.

[Ponnuvel Palaniyappan (pponnuvel)]

To clarify for anyone stumbling on this:
Currently co-locating charms that may conflict isn't supported. This LP bug is a feature request.

The recommendation is to *not* co-locate charms that may conflict with each other and use LXD containers (or VMs) if multiple charms are to be located on the same physical machine.

[Balazs Gibizer (balazs-gibizer)]

I don't see how this relates to the nova project so I close this as invalid.