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Apache Cassandra is a highly scalable, distributed NoSQL database designed to handle large amounts of data across many commodity servers, providing high availability with no single point of failure. It is widely used for its ability to manage large volumes of data with high performance and reliability.
The CassandraNodeUnreachable alert indicates that a Cassandra node is not reachable from other nodes in the cluster. This can lead to issues with data consistency and availability, as the cluster relies on communication between nodes to function correctly.
When a node becomes unreachable, it means that other nodes in the cluster cannot communicate with it. This could be due to network issues, node failures, or misconfigurations. The alert is triggered by Prometheus when it detects that a node is not responding to requests or is not part of the cluster's gossip protocol.
Ensure that the network connections between nodes are intact. You can use tools like PingPlotter or ping
and traceroute
commands to diagnose network issues.
ping
traceroute
Log into the Cassandra node and check its status using the nodetool
utility. This will help you determine if the node is up and running.
nodetool status
Look for the node in question and check its status. If it is down, investigate the logs for any errors or issues.
Ensure that the node is properly configured. Check the cassandra.yaml
file for any misconfigurations, especially in the listen_address
and rpc_address
settings.
cat /etc/cassandra/cassandra.yaml | grep 'listen_address'
cat /etc/cassandra/cassandra.yaml | grep 'rpc_address'
If the node is down or unresponsive, try restarting it. This can often resolve transient issues.
sudo systemctl restart cassandra
For more detailed troubleshooting, refer to the official Cassandra documentation or the Prometheus documentation for alerting setup and management.
By following these steps, you should be able to diagnose and resolve the CassandraNodeUnreachable alert, ensuring your Cassandra cluster remains healthy and operational.
(Perfect for DevOps & SREs)
(Perfect for DevOps & SREs)