[Linux-cluster] delete node

[Scott McClanahan]

On Tue, 2007-04-10 at 13:54 +0100, Patrick Caulfield wrote:
> Scott McClanahan wrote:
> > On Tue, 2007-04-10 at 03:37 -0400, Patrick Caulfield wrote:
> >> Scott McClanahan wrote:
> >>> Hello, we are running CentOS 4.3 and the latest cluster suite
> >> packages
> >>> from the csgfs yum repository for this release and need to delete a
> >>> cluster member.  According to the documentation we need to restart
> >> all
> >>> cluster related services on all remaining nodes in the cluster after
> >> the
> >>> node has been removed.  This is a four node cluster so removing one
> >> node
> >>> obviously degrades the cluster to three nodes, but we can have the
> >>> remaining cluster members recalculate the number of votes to remain
> >>> quorate.  It still surprises me that we have to bring down the
> >> entire
> >>> cluster just because we are deleting a node.  Any feedback as to why
> >>> this might be?
> >>>
> >>
> >> You only need to reboot the whole cluster if you want to remove all
> >> trace of the
> >> node from /proc/cluster/nodes. If you're not bothered about that them
> >> just
> >> remove with "cman_tool leave remove" and forget about it.
> >>
> >> --
> >> Patrick
> >>
> >> Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod
> >> Street,
> >> Windsor, Berkshire, SL4 ITE, UK.
> >> Registered in England and Wales under Company Registration No. 3798903
> >>
> >> --
> >> Linux-cluster mailing list
> >> Linux-cluster at redhat.com
> >> https://www.redhat.com/mailman/listinfo/linux-cluster
> >>
> > Ok, thanks for the answer.  To further elaborate my concern, if I want
> > to rebuild an existing cluster member and reintroduce it to the cluster
> > how do you suspect the cluster would handle that.  What would be the
> > best way to rebuild an existing cluster member.  Other than the traces
> > of node details in /proc/cluster/nodes is there any kind of state kept
> > locally on these cluster nodes that would cause issues if I rebuild the
> > node and attempt to transparently add it back to the cluster.
> >
> > Would I need to delete the cluster member from the cluster config using
> > the proper utilities and then add it again?
> >
> > Could I avoid having to delete the cluster member at all from the
> > cluster and simply rebuild/reintroduce?
> 
> If the rebuilt node has the same node name and IP address (and cluster sofware,
> obviously) then there will be no problems. The other members of the cluster will
> welcome it with open arms as an old friend.
> 
> If you give it a different name/ip address then it will appear in the cluster as
> a new node and its old incarnation will remain in the list as 'dead'.
> 
> > Why?  :)
> 
> All the existing members care about the old node is that it has the same name,
> IP address and node ID. Anything else is nothing to do with them really, or can
> be sorted out at run time.
> 
Sorry to be so chatty but just to be sure (this is production), I can
just rebuild the node without deleting it from the config?  I will
obviously need to copy the cluster.conf file to the newly built node but
I thought that the node ID was "assigned" during the joining process of
cluster membership.  If that is the case and as long as I don't manually
override the node ID, do I really have to worry about anything other
than the hostname/IP?  Not sure if it helps to reiterate that this is
the cluster suite software built for RHEL version 4.3.

> 
>