The Deploying an HA NFS Cluster with DRBD and DRBD Reactor on RHEL 9 or AlmaLinux 9 how-to technical guide gives instructions for setting up and configuring a high-availability (HA) NFS 3-node cluster, by using DRBD® and DRBD Reactor.
This popular guide walks you through how to set up this HA cluster by using open source software and even gives you instructions for configuring multiple HA NFS exported file systems.
DRBD Reactor is open source software, developed by LINBIT®, that reacts and responds to DRBD events. One of its primary uses is as a cluster resource manager (CRM) that is simpler to configure and implement than a Pacemaker and Corosync solution. You can even use Open Cluster Framework (OCF) resource agents in your configurations, just as you might when configuring a Pacemaker cluster.
After following the instructions in the guide, you will have multiple HA NFS exported file systems on a LAN. If one of the cluster nodes fails, DRBD Reactor will fail over the NFS exports to another node. A failover event will not stop access to the NFS exports, even if the client is in the middle of a read or write operation to an NFS exported file system. Because of DRBD data replication, a node that takes over after a failover will have a perfect, up-to-date copy of the data on the NFS exports. You and your users will not miss a beat. You can even verify this by failing over while playing an audio file that might be hosted on one of the HA NFS exports.
The guide also shows you how to use an OCF resource agent to configure a virtual IP (VIP) address so that no matter which node in your cluster is running services and hosting your NFS exports, you can reach your exports from a single IP address.
You can download the guide for free here. You can find DRBD Reactor source code at its GitHub project page. You can learn more about DRBD Reactor by reading its dedicated chapter in the DRBD User’s Guide.
Changelog
2023-02-01:
- Originally published announcement post.
2024-07-19:
- Added that software used is open source.
- Mentioned that updated technical guide gives instructions for configuring multiple HA NFS exported file systems.
- Added mention of VIP address.
- Made minor language touch-ups.
