DevOps Documentation
Comprehensive, real troubleshooting guides for modern DevOps technologies.
Docker Container Exit Code 137 (OOM Killed)
A container stops unexpectedly with exit code 137 — the kernel's OOM killer terminated it for using too much memory.
Docker Image Pull Access Denied
docker pull or docker run fails with a pull access denied error against a registry.
Terraform State Lock Error
terraform plan or apply fails immediately because the state is locked by a previous, possibly stale, run.
Terraform Provider Authentication Error
terraform plan fails at the provider level before reaching any resource, due to missing or invalid cloud credentials.
Jenkins Pipeline Timeout Error
A pipeline stage or whole build is aborted by a timeout before its real work finishes.
GitHub Actions Cache Restore Failure
A workflow's cache step reports a miss every run, so dependencies reinstall from scratch instead of restoring.
Ansible SSH Connection Failed
Ansible cannot target hosts via SSH.
Nginx 502 Bad Gateway Error
Nginx returns 502 when it can't get a valid response from the upstream application server.
Git Merge Conflict Resolution
Merging or rebasing fails with conflict markers because the same lines changed differently on both sides.