Learn how to avoid Split Brain in HAProxy & Keepalived. Our HAProxy Support team is here to help you with your questions and concerns.

How to avoid Split Brain in HAProxy & Keepalived

Split Brain in relation to HAProxy and Keepalived refers to the nodes in a high-availability cluster losing communication with each other.

In addition, this causes multiple nodes to act as the active node at the same time. This leads to conflicting configurations and a lack of proper failover. In other words, it causes service disruptions or outages.

When a Split brain occurs, the master and backup nodes believe they are the active node as they cannot communicate to decide which node should hold the master role.

Hence, multiple nodes start responding to traffic as if they are active nodes. It is no surprise that preventing a split brain is key to the integrity and high availability of the cluster.

Some of the techniques to overcome and avoid split-brain include:

• Quorum-based Configuration:

  The quorum-based configuration involves using a minimum number of nodes for the cluster to function correctly. If the number of available nodes falls below this minimum, the cluster avoids becoming active and waits for the minimum number of nodes to be available again.
• Monitoring and Health Checks:

  We can use proper monitoring and health checks to detect node failures or communication issues early. Health checks help make sure that nodes are still responding correctly.
• STONITH (Shoot The Other Node In The Head):

  STONITH devices or mechanisms help to forcefully remove a node that is believed to be in a split-brain state. This ensures that only one node can claim the master role at a time.
• Network Redundancy:

  We can use network redundancy and proper network configuration to reduce the chances of network-related issues that cause split-brain scenarios.

According to our experts, it is important to carefully design and configure our high-availability setup to prevent split brain and test our failover mechanisms. Furthermore, regular monitoring and testing are key to identifying and addressing any issues.

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Conclusion

In summary, our Support Techs demonstrated how to avoid Split Brain in HAProxy & Keepalived.