Docker "Conflict. The container name is already in use" in CI

A docker run --name <name> collided with an existing container. Conflict. The container name "/<name>" is already in use means a prior container with that name still exists (running or stopped) and was not removed.

What this error means

A docker run --name api ... fails with Error response from daemon: Conflict. The container name "/api" is already in use by container "<id>". You have to remove (or rename) that container to be able to reuse that name.

docker

docker: Error response from daemon: Conflict. The container name "/api" is already
in use by container "9f3c...". You have to remove (or rename) that container to reuse that name.

Common causes

A previous container with the same name was not removed

A fixed --name reused across jobs (or a re-run) collides with the leftover container from the prior run on a persistent runner.

A stopped container still holds the name

Container names are reserved even when stopped; a stopped container with that name blocks reuse until removed.

How to fix it

Remove the existing container or use --rm

Remove the old container first, or run with --rm / a unique name.

Terminal

docker rm -f api 2>/dev/null || true
docker run --name api --rm myorg/api:1.4.2
# or avoid fixed names:
docker run myorg/api:1.4.2   # daemon assigns a unique name

Use unique per-run names

Suffix the name with a run identifier so collisions cannot happen.

.github/workflows/build.yml

docker run --name "api-${{ github.run_id }}" --rm myorg/api:1.4.2

How to prevent it

Use --rm or unique per-run container names in CI.
Remove fixed-name containers before re-running on persistent runners.
Avoid hard-coded --name values shared across jobs.