In the next 45 minutes, I will give you an overview of GlusterFS/Pacemaker integration.
We'll break this down into 3 parts.
1
What's Pacemaker, really?
2
How do I use GlusterFS storage for Pacemaker?
3
How do I manage GlusterFS storage with Pacemaker?
1
Pacemaker is the state of the art high availability stack for Linux.
It is built on the Corosync cluster messaging subsystem.
It is entirely application agnostic.
Application management is through resource agents.
70
It is the default cluster stack on Debian, SUSE, Ubuntu, and CentOS.
Pacemaker is a Technology Preview in RHEL 6, and will be the default HA stack in RHEL 7.
Here is a simple 3 node Pacemaker cluster running on Debian.
alice
bob
charlie
2
Pacemaker is storage agnostic.
One storage option for Pacemaker: NAS
As in CIFS or NFS.
Simple and easy, no locking issues.
But: very limited scaleout capability
Another: single-instance shared storage.
Requires GFS, OCFS2 or similar.
Another: DRBD.
Limited scalability, limited multi-master support.
Pacemaker allows us to easily use GlusterFS mounts for storage.
We can use the general-purpose
ocf:heartbeat:Filesystem resource agent.
alice
bob
charlie
3
In 3.4, GlusterFS will ship with Pacemaker resource
agents to manage both
glusterd and individual
volumes.
They allow us to auto-recover GlusterFS
services on systems where neither upstart nor
systemd are available.
ocf:glusterfs:glusterd manages
glusterd on all GlusterFS server
nodes.
ocf:glusterfs:volume manages individual bricks.
alice
bob
charlie
And of course we can also combine everything.
What we could be doing in the near future:
100% open-source cross-site high availability with automatic failover.
Can you hear a manager squeal?
Pacemaker can already do this.
GlusterFS can't (yet).
Thanks to:
Bartek Szopka @bartaz for impress.js
Markus Gutschke for shellinabox (and his recipe collection!)
