Sharing in details, no, because i dont have all the conf and source. Furthermore, as my company paid for it, the management team choose to use Red Hat Enterprise Linux 6+ build as clusters with the High Availability Add On and Resilient Storage Add On, using GFS2 witch, unfortunatly are not free.
the big picture is about setting Policies for RHEL High Availability Clusters, using different steps:
- Red Hat’s OpenStack build in cluster mode
- Deploying Ceph Storage environment and integrating with OpenStac
- Specific Network configuration using Virtual Extensible Local Area Network (VXLAN) network type and Modular Layer 2 (ML2) plugin.
- Setting specifics environment using Pacemaker and HAProxy.
- CloudForms implementation across differents data centers
- Creation of a High Availability and Resilient Storage with corosync using GFS2
This kind of set-up are out the the public scope, as they requieres:
- licenses fee ( quiet expensives ones )
- metal bare hardware
- data center hosting
- Specific real high speed links
- KNOWLEDGE or external help ( quiet expensives ones too !!! )
When all this is done, you end’s up with a HA server’s network limited to a max of 16 nodes.
Unfortunatly, there’s still some limitations like (from my “pense-bete notes”:
Oracle RAC on GFS2 is unsupported on all versions of RHEL
Staged/rolling upgrades between any major release is not supported. For example, a rolling upgrade of Red Hat Enterprise Linux 5 to Red Hat Enterprise Linux 6.
Cluster node count greater than 16 is unsupported
Usage of MD RAID for cluster storage is unsupported
Snapshotting of clustered logical volumes is unsupported unless that volume has been activated exclusively on one node (as of release lvm2-2.02.84-1.el5 in RHEL 5.7 or lvm2-2.02.83-3.el6 in RHEL 6.1)
Using multiple SAN devices to mirror GFS/GFS2 or clustered logical volumes across different subsets of the cluster nodes is unsupported
Corosync using broadcast instead of multicast in RHEL 6 is unsupported (except for demo and pre-sales engagements)
In RHEL 5.6+ broadcast mode is supported with certain restrictions as an alternative to multicast.
In RHEL 6.2+ UDP unicast is is fully supported as an alternative to multicast.
Corosync’s Redundant Ring Protocol is a Technology Preview in RHEL 6.0 - 6.3, it because fully supported on RHEL 6.4+ as described in the following article.
The supported limits for the heartbeat token timeout are described in the following reference: What are the supported limits for heartbeat token timeout in Red Hat Cluster Suite?
High Availability Resources
Usage of NFS in an active/active configuration on top of either GFS or GFS2 is unsupported
Usage of NFS and Samba on top of same GFS/GFS2 instance is unsupported
Running Red Hat High Availability Add-On or clusters on virtualized guests his limited support.
The conclusion of this: HA is very high end in terms of hardware, the overall cost is pretty important, the IT management knowledge is quiet challenging !