docker/cli · error

error: this node is not part of a swarm

Error message

error: this node is not part of a swarm

What it means

Thrown by runUnlock (cli/command/swarm/unlock.go:51) when an Info call reports LocalNodeState == Inactive, meaning this engine has never joined or initialized a swarm. There is nothing to unlock, so the command refuses rather than prompting for a key.

Solutions

1. Initialize or join a swarm first: `docker swarm init` (manager) or `docker swarm join --token <t> <ip:2377>`.
2. Confirm the node's swarm state with `docker info` (look for `Swarm: inactive`).

Example fix

// before (not in a swarm)
docker swarm unlock   # -> error: this node is not part of a swarm

// after
docker swarm init   # or: docker swarm join --token <t> <ip:2377>

res, err := apiClient.Info(ctx, client.InfoOptions{})
if err != nil { return err }
if res.Info.Swarm.LocalNodeState == swarm.LocalNodeStateInactive {
	return errors.New("node is not in a swarm; init or join first")
}

When it happens

Trigger: Running `docker swarm unlock` on a node that was never part of a swarm, or that left the swarm (`docker swarm leave`) and is now inactive.

Common situations: Wrong host; fresh install; swarm was dissolved/left; node reset to factory state.

Related errors

• error: swarm is not locked
• node ID not found in /info
• when using secret driver secret data must be empty
• error reading from STDIN: data is empty
• secret file is required

AI-assisted analysis of docker/cli@4f84911bfe (2026-08-07). Data as JSON: /api/errors/58c9687175ba0da1. Report an issue: GitHub.

Appendix: source

Thrown at cli/command/swarm/unlock.go:51

		DisableFlagsInUseLine: true,
	}

	return cmd
}

func runUnlock(ctx context.Context, dockerCLI command.Cli) error {
	apiClient := dockerCLI.Client()

	// First see if the node is actually part of a swarm, and if it is actually locked first.
	// If it's in any other state than locked, don't ask for the key.
	res, err := apiClient.Info(ctx, client.InfoOptions{})
	if err != nil {
		return err
	}

	switch res.Info.Swarm.LocalNodeState {
	case swarm.LocalNodeStateInactive:
		return errors.New("error: this node is not part of a swarm")
	case swarm.LocalNodeStateLocked:
		break
	case swarm.LocalNodeStatePending, swarm.LocalNodeStateActive, swarm.LocalNodeStateError:
		return errors.New("error: swarm is not locked")
	}

	key, err := readKey(dockerCLI.In(), "Enter unlock key: ")
	if err != nil {
		return err
	}

	_, err = apiClient.SwarmUnlock(ctx, client.SwarmUnlockOptions{
		Key: key,
	})
	return err
}

func readKey(in *streams.In, prompt string) (string, error) {

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