Chapter 3. An active/passive NFS Server in a Red Hat High Availability Cluster

This chapter describes how to configure a highly available active/passive NFS server on a two-node Red Hat Enterprise Linux High Availability Add-On cluster using shared storage. The procedure uses pcs to configure Pacemaker cluster resources. In this use case, clients access the NFS file system through a floating IP address. The NFS server runs on one of two nodes in the cluster. If the node on which the NFS server is running becomes inoperative, the NFS server starts up again on the second node of the cluster with minimal service interruption.
This use case requires that your system include the following components:
  • Two nodes, which will be used to create the cluster running the Apache HTTP server. In this example, the nodes used are z1.example.com and z2.example.com.
  • A power fencing device for each node of the cluster. This example uses two ports of the APC power switch with a host name of zapc.example.com.
  • A public virtual IP address, required for the NFS server.
  • Shared storage for the nodes in the cluster, using iSCSI or Fibre Channel.
Configuring a highly available active/passive NFS server on a two-node Red Hat Enterprise Linux High requires that you perform the following steps.
  1. Create the cluster that will run the NFS server and configure fencing for each node in the cluster, as described in Section 3.1, “Creating the NFS Cluster”.
  2. Configure an ext4 file system mounted on the LVM logical volume my_lv on the shared storage for the nodes in the cluster, as described in Section 3.2, “Configuring an LVM Volume with an ext4 File System”.
  3. Configure an NFS share on the shared storage on the LVM logical volume, as described in Section 3.3, “NFS Share Setup”.
  4. Ensure that only the cluster is capable of activating the LVM volume group that contains the logical volume my_lv, and that the volume group will not be activated outside of the cluster on startup, as described in Section 3.4, “Exclusive Activation of a Volume Group in a Cluster”.
  5. Create the cluster resources as described in Section 3.5, “Configuring the Cluster Resources”.
  6. Test the NFS server you have configured, as described in Section 3.6, “Testing the Resource Configuration”.

3.1. Creating the NFS Cluster

Use the following procedure to install and create the NFS cluster.
  1. Install the cluster software on nodes z1.example.com and z2.example.com, using the procedure provided in Section 1.1, “Cluster Software Installation”.
  2. Create the two-node cluster that consists of z1.example.com and z2.example.com, using the procedure provided in Section 1.2, “Cluster Creation”. As in that example procedure, this use case names the cluster my_cluster.
  3. Configure fencing devices for each node of the cluster, using the procedure provided in Section 1.3, “Fencing Configuration”. This example configures fencing using two ports of the APC power switch with a host name of zapc.example.com.