DevOps

Overview Seeing “Service <name> failed to build” during docker compose build or up means the image build for that service failed. The message is generic; the real cause is in the build output for the last failed step. This guide......

Overview Git "RPC failed" errors usually occur during networked operations (push, clone, fetch) when the HTTP/HTTPS transport closes unexpectedly, times out, or chokes on large packfiles. Common messages: RPC failed; curl 18......

Overview Multi-arch images bundle variants for different CPU architectures (amd64, arm64, arm/v7, etc.). Mismatches cause errors like: no matching manifest for linux/amd64 in the manifest list entries exec format error This guide shows......

Overview In Docker and BuildKit, the messages "context canceled" or "rpc error: code = Canceled" mean the build’s controlling context was terminated. This is not a specific step failure; it’s a cancellation signal.......

Overview AppArmor (Ubuntu/Debian) and SELinux (Fedora/RHEL/CentOS) can block Docker containers from reading files, mounting paths, or performing syscalls. Typical errors: AppArmor: apparmor="DENIED" operation="..."......

Overview Docker isolates processes with namespaces, capabilities, seccomp, and LSMs (AppArmor/SELinux). Privileged operations (mount, loop devices, iptables, FUSE, eBPF) often fail with: Operation not permitted. This guide shows practical......

Overview In Docker, the error "Cannot start service …: bpf: operation not permitted" means the container tried to use the bpf() syscall (load/attach eBPF programs or maps) without the necessary Linux capabilities or was blocked......

Overview This error typically appears during docker run or docker compose up: Cannot start service <name>: failed to create shim task: address already in use It usually means one of the following: A host port you are publishing is......

Overview If you see: unknown shorthand flag: -d when running docker compose, it almost always means the -d flag was placed before the subcommand. In Docker Compose (v1 and v2), options belong to the subcommand (up), not to the compose......

Overview The error "docker: 'compose' is not a docker command" means the Docker CLI cannot find the Compose v2 plugin. Docker Compose v2 is invoked as docker compose and is distributed as a CLI plugin. Without it, the docker CLI......

Why you see this error If you run docker-compose and get command not found, you likely: Don’t have legacy Compose v1 installed, or it was removed. Are on a system where Compose v2 is installed as a Docker CLI plugin and should be invoked......

What this fixes Errors like: unknown flag: --build, unknown flag: --no-cache, or -d used in the wrong place Running options before the subcommand (e.g., docker compose --build up) Mixing flags that belong to build with up, or placing......