Deploying a VIP on a Pacemaker Cluster

09 May 2024

"Three men throwing a ball back and forth in green grass field as seen from above."

In this guide, I will show you how to configure a virtual ip address (VIP) on a pacemaker cluster. This VIP will float between the nodes in the cluster and allow users to connect to a single IP address to access the service.

Pre-requisites

This guide assumes you have a basic understanding of Pacemaker and have a cluster already set up. If you don’t have a cluster set up, you can follow my guide here in this post

You will also need a static ip address that is not in use on your network.

Deploying a VIP

In this example, I will be using the vip of 192.168.30.10/24. You should replace this with an ip address thatis not in use on your network.

Checking to make sure the VIP is not in use

ping 192.168.30.10
toggle console output: 
PING 192.168.30.10 (192.168.30.10) 56(84) bytes of data.
From 192.168.30.186 icmp_seq=1 Destination Host Unreachable
From 192.168.30.186 icmp_seq=2 Destination Host Unreachable
From 192.168.30.186 icmp_seq=3 Destination Host Unreachable
^C
--- 192.168.30.10 ping statistics ---
4 packets transmitted, 0 received, +3 errors, 100% packet loss, time 3055ms

If nothing returns, then the ip address may not be in use. I am assuming you are deploying this in a lab environment and not in production. Obviously, in production, you should be getting an ip address from IPAM or your network team.

First node only

sudo pcs resource create vip ocf:heartbeat:IPaddr2 ip=192.168.30.10 cidr_netmask=24 op monitor interval=10s

Let’s break down the command:

Verify the VIP is running a node

sudo pcs status
toggle console output: 
Cluster name: democluster
Cluster Summary:
  * Stack: corosync (Pacemaker is running)
  * Current DC: node2 (version 2.1.7-5.el9_4-0f7f88312) - partition with quorum
  * Last updated: Sun May 12 05:42:43 2024 on node1
  * Last change:  Sun May 12 05:42:32 2024 by root via root on node1
  * 3 nodes configured
  * 4 resource instances configured

Node List:
  * Online: [ node1 node2 node3 ]

Full List of Resources:
  * Clone Set: nginx-clone [nginx]:
    * Started: [ node1 node2 node3 ]
  * vip (ocf:heartbeat:IPaddr2):         Started node1

Daemon Status:
  corosync: active/disabled
  pacemaker: active/disabled
  pcsd: active/enabled

Testing the VIP with ping

ping 192.168.30.10
toggle console output: 
PING 192.168.30.10 (192.168.30.10) 56(84) bytes of data.
64 bytes from 192.168.30.10: icmp_seq=1 ttl=64 time=0.082 ms
64 bytes from 192.168.30.10: icmp_seq=2 ttl=64 time=0.067 ms
64 bytes from 192.168.30.10: icmp_seq=3 ttl=64 time=0.069 ms
^C
--- 192.168.30.10 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2074ms
rtt min/avg/max/mdev = 0.067/0.072/0.082/0.006 ms

Now that the VIP resource is up, you should be able to ping the ip address from any node in the cluster.



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