# Troubleshoot

Diagnose and resolve issues with ScyllaDB Operator, ScyllaDB clusters, and related infrastructure.

## By symptom

| Symptom                                                            | Guide                                                                                                                                                                                                 |
|--------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Pods restarting unexpectedly                                       | [Investigate pod restarts](https://operator.docs.scylladb.com/stable/troubleshoot/investigate-restarts.md)                                                                                            |
| Application cannot connect to ScyllaDB                             | [Connect Your App](https://operator.docs.scylladb.com/stable/connect-your-app/index.md) and [Set up networking](https://operator.docs.scylladb.com/stable/deploy-scylladb/set-up-networking/index.md) |
| Upgrade failed or stuck                                            | [Upgrade](https://operator.docs.scylladb.com/stable/upgrade/index.md)                                                                                                                                 |
| Node replace stuck or failed                                       | [Recover from a failed node replace](https://operator.docs.scylladb.com/stable/troubleshoot/recover-from-failed-replace.md)                                                                           |
| Scale-down stuck with leftover Pods of removed nodes               | [Recover from a stuck scale-down](https://operator.docs.scylladb.com/stable/troubleshoot/recover-from-stuck-scale-down.md)                                                                            |
| Pod can’t start after a spec change, and reverting it doesn’t help | [Recover from a stuck config change](https://operator.docs.scylladb.com/stable/troubleshoot/recover-from-stuck-config-change.md)                                                                      |
| Slow queries, throughput degradation, or CPU pinning not working   | [Troubleshoot performance](https://operator.docs.scylladb.com/stable/troubleshoot/troubleshoot-performance.md)                                                                                        |
| Need to change log level without a rolling restart                 | [Change log level](https://operator.docs.scylladb.com/stable/troubleshoot/change-log-level.md)                                                                                                        |
| Need to collect data for a support ticket                          | [Collect debugging information](https://operator.docs.scylladb.com/stable/troubleshoot/collect-debugging-information/index.md)                                                                        |
| Need to configure or collect core dumps                            | [Collect core dumps](https://operator.docs.scylladb.com/stable/troubleshoot/configure-coredumps.md)                                                                                                   |

* [Investigate pod restarts](https://operator.docs.scylladb.com/stable/troubleshoot/investigate-restarts.md)
* [Change log level on a live cluster](https://operator.docs.scylladb.com/stable/troubleshoot/change-log-level.md)
* [Recover from a failed node replace](https://operator.docs.scylladb.com/stable/troubleshoot/recover-from-failed-replace.md)
* [Recover from a stuck scale-down](https://operator.docs.scylladb.com/stable/troubleshoot/recover-from-stuck-scale-down.md)
* [Recover from a stuck config change](https://operator.docs.scylladb.com/stable/troubleshoot/recover-from-stuck-config-change.md)
* [Troubleshoot performance](https://operator.docs.scylladb.com/stable/troubleshoot/troubleshoot-performance.md)
* [Collect debugging information](https://operator.docs.scylladb.com/stable/troubleshoot/collect-debugging-information/index.md)
* [Collect core dumps](https://operator.docs.scylladb.com/stable/troubleshoot/configure-coredumps.md)