[ClusterLabs] What are RHCS and LHA fence agents?

[Reid Wahl]

On Mon, Apr 7, 2025 at 4:30 PM Reid Wahl <nwahl at redhat.com> wrote:
>
> On Mon, Apr 7, 2025 at 4:24 PM Reid Wahl <nwahl at redhat.com> wrote:
> >
> > What are RHCS and LHA fence agents, and what are they used for today?
> >
> > I would have guessed from the names and what commit messages I've found that
> > * RHCS refers to Red Hat Cluster Suite (a.k.a. cman clusters), which
> > has been unsupported since RHEL 7

Okay, we really ought to rename this stuff soon. Pacemaker uses the
term "rhcs" to mean "standard fence agents" -- the kind that are from
the ClusterLabs/fence-agents repository. Pacemaker actually decides
"this agent is an RHCS-style agent" if it lives in
`PCMK__FENCE_BINDIR` (which is /usr/sbin on my machine) and starts
with "fence_".

Sigh. Sorry to bother everyone. I'm getting frustrated by unclear and
legacy code :)

> > * LHA refers to Linux-HA, which... isn't that from Heartbeat clusters
> > or something?
> >
> > All of this is from before my time as a developer for Pacemaker. I'm
> > trying to understand what's still relevant and how.
> >
> > I'm including Yan Gao from SUSE, as they have some commits in the past
> > few years related to both agent types.
>
> Related question: Is anyone aware of ANY fence agent that supports a
> "nodeid" parameter? We seem to have some dead code in Pacemaker
> related to that. I don't see any agent in fence-agents or cluster-glue
> (which is apparently related to LHA fencing) that accepts a nodeid
> parameter.

The nodeid question still stands.

>
> --
> Regards,
>
> Reid Wahl (He/Him)
> Senior Software Engineer, Red Hat
> RHEL High Availability - Pacemaker



-- 
Regards,

Reid Wahl (He/Him)
Senior Software Engineer, Red Hat
RHEL High Availability - Pacemaker