Thanos is an open-source project that provides highly available Prometheus setup with long-term storage capabilities. It is designed to scale out Prometheus by enabling global querying, unlimited retention, and high availability. Thanos consists of multiple components, including the Querier, Ruler, Store, and Compactor, each serving a specific role in the ecosystem.
When using Thanos, you might encounter an error message stating: query: failed to connect to Ruler
. This symptom indicates that the Querier component is unable to establish a connection with the Ruler component, which is responsible for evaluating Prometheus recording and alerting rules.
In the logs or user interface, you may see error messages related to connectivity issues between the Querier and the Ruler. This can lead to failed queries or missing alert evaluations.
The error query: failed to connect to Ruler
typically arises due to network connectivity problems. The Querier needs to communicate with the Ruler to fetch rule evaluations, and any disruption in this communication can trigger the error.
To resolve the connectivity issue between the Querier and the Ruler, follow these steps:
Ensure that the network allows communication between the Querier and the Ruler. You can use tools like ping
or telnet
to test connectivity:
ping <ruler-host>
If ping
is successful, try connecting to the Ruler's port:
telnet <ruler-host> <ruler-port>
Review the Querier's configuration to ensure the Ruler's address and port are correctly specified. This can typically be found in the Querier's configuration file or environment variables.
--query.replica-label=ruler
--store=dnssrv+_grpc._tcp.ruler:10901
Verify that the Ruler component is up and running. You can check the status of the Ruler service using system commands or by accessing its logs:
kubectl get pods -n <namespace> | grep ruler
kubectl logs <ruler-pod-name> -n <namespace>
For more information on Thanos and troubleshooting, consider visiting the following resources:
By following these steps, you should be able to resolve the connectivity issue between the Querier and the Ruler in your Thanos setup.
(Perfect for DevOps & SREs)
(Perfect for DevOps & SREs)