What causes "container {container_id} was running." in cross-rs/cross?

Nothing required — cross stops and cleans the container automatically; investigate only if this repeats.

container was running.

Error message

container {container_id} was running.

What it means

At the start of a remote run, cross reuses or cleans up a leftover container from a previous run. If the container with the expected ID is still running, it warns, stops it with the default timeout, and continues cleanup (removing it if it exists).

Solutions

Nothing required — cross stops and cleans the container automatically; investigate only if this repeats.
Avoid killing cross mid-build; use `crossutil`/docker CLI to clean leftover containers (`docker rm -f <container_id>`).
Ensure no two cross remote runs execute concurrently in the same Docker context.

Example fix

# before: leftover container from interrupted run
 docker ps # shows cross container running

# after: clean up manually if needed
docker rm -f <container_id>
cross build --remote --target aarch64-unknown-linux-gnu

Defensive patterns

Strategy: fallback

Validate before calling

# Detect a leftover running container before invoking cross
id=$(docker ps -q --filter name=cross-)
[ -n "$id" ] && docker rm -f "$id"

Try / catch

// Warning is auto-handled; retry only if cleanup itself failed
if let Err(e) = run() {
    if e.to_string().contains("was running") { std::thread::sleep(STOP_GRACE); retry(); } else { return Err(e); }
}

Prevention

Let cross finish or use its own cancellation path instead of SIGKILL
Avoid concurrent cross remote runs in one Docker context
Prune leftover containers after CI cancellations

When it happens

Trigger: run() finds a previous remote-build container (from a crashed/interrupted run) whose state is not stopped, so container.state(msg_info)? returns running and the warn branch fires.

Common situations: A previous cross remote build was killed (Ctrl-C, CI timeout, machine reboot) leaving the container running; concurrent cross runs colliding on the same container ID.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

AI-assisted analysis of cross-rs/cross@8c1a8aa4b6 (2026-09-13). Data as JSON: /api/errors/8b0ad9bff6a2acf8. Report an issue: GitHub.

Appendix: source

Thrown at src/docker/remote.rs:804

        let existing = DockerVolume::existing(engine, toolchain_dirs.toolchain(), msg_info)?;
        if existing.iter().any(|v| v == &toolchain_id) {
            VolumeId::Keep(toolchain_id)
        } else {
            let partial = format!("{VOLUME_PREFIX}{}", toolchain_dirs.toolchain());
            if existing.iter().any(|v| v.starts_with(&partial)) {
                msg_info.warn(format_args!(
                    "a persistent volume does not exists for `{0}`, but there is a volume for a different version.\n > Create a new volume with `cross-util volumes create --toolchain {0}`",
                    toolchain_dirs.toolchain()
                ))?;
            }
            VolumeId::Discard
        }
    };

    let container = DockerContainer::new(engine, &container_id);
    let state = container.state(msg_info)?;
    if !state.is_stopped() {
        msg_info.warn(format_args!("container {container_id} was running."))?;
        container.stop_default(msg_info)?;
    }
    if state.exists() {
        msg_info.warn(format_args!("container {container_id} was exited."))?;
        container.remove(msg_info)?;
    }

    // 2. create our volume to copy all our data over to
    // we actually use an anonymous volume, so it's auto-cleaned up,
    // if we're using a discarded volume.

    // 3. create our start container command here
    let mut docker = engine.subcommand("run");
    docker.add_userns();
    options
        .image
        .platform
        .specify_platform(&options.engine, &mut docker);

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