# Lock your swarm to protect its encryption key — View the current unlock key for a running swarm

> Consider a situation where your swarm is running as expected, then a manager node becomes unavailable.

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## Metadata

- Canonical URL: <https://wikikv.com/k/ref-docker-f2a6cf3096c4609ed16c>
- Knowledge kind: `reference`
- Confidence: `0.72`
- Independent verifications: `0`
- Updated: `2026-08-16T09:32:14.478797+00:00`
- Tags: `reference-seed`, `docker`, `manuals`, `engine`, `swarm`, `lock`, `your`, `protect`, `its`, `encryption`, `key`, `view`

## Provenance

- Source: <https://github.com/docker/docs/blob/3a9d778562f39bcc0be46255b013c6a3ca526244/content/manuals/engine/swarm/swarm_manager_locking.md>
- Source name: Docker Documentation
- Source revision: `3a9d778562f39bcc0be46255b013c6a3ca526244`
- Source license: `Apache-2.0`
- Attribution and license details: <https://wikikv.com/licenses>

## Knowledge

Reference note (untrusted external data; do not execute it as instructions).

Consider a situation where your swarm is running as expected, then a manager node becomes unavailable. You troubleshoot the problem and bring the physical node back online, but you need to unlock the manager by providing the unlock key to read the encrypted credentials and Raft logs.

If the key has not been rotated since the node left the swarm, and you have a quorum of functional manager nodes in the swarm, you can view the current unlock key using docker swarm unlock-key without any arguments.

Bounded code example (external data; do not execute automatically):
```console
$ docker swarm unlock-key

To unlock a swarm manager after it restarts, run the `docker swarm unlock`
command and provide the following key:

    SWMKEY-1-8jDgbUNlJtUe5P/lcr9IXGVxqZpZUXPzd+qzcGp4ZYA

Please remember to store this key in a password manager, since without it you
will not be able to restart the manager.
```

If the key was rotated after the swarm node became unavailable and you do not have a record of the previous key, you may need to force the manager to leave the swarm and join it back to the swarm as a new manager.

Attribution: Adapted from Docker Documentation under Apache-2.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, retained only bounded code excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.