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k3s secrets-encrypt

K3s supports enabling secrets encryption at rest. For more information, see Secrets Encryption.

Secrets Encryption Tool

Version Gate

Available as of v1.21.8+k3s1

K3s contains a CLI tool secrets-encrypt, which enables automatic control over the following:

  • Disabling/Enabling secrets encryption
  • Adding new encryption keys
  • Rotating and deleting encryption keys
  • Reencrypting secrets
warning

Failure to follow proper procedure for rotating encryption keys can leave your cluster permanently corrupted. Proceed with caution.

New Encryption Key Rotation (Experimental)

Version Gate

Available as of v1.28.1+k3s1. This new version of the tool utilized K8s automatic config reloading which is currently in beta. GA is expected in v1.29.0

For older releases, see Encryption Key Rotation Classic

To rotate secrets encryption keys on a single-server cluster:

  1. Start the K3s server with the flag --secrets-encryption

    note

    Starting K3s without encryption and enabling it at a later time is currently not supported.

  2. Rotate secrets encryption keys

    k3s secrets-encrypt rotate-keys
  3. Wait for reencryption to finish. Watch the server logs, or wait for:

    $ k3s secrets-encrypt status
    Encryption Status: Enabled
    Current Rotation Stage: reencrypt_finished

Encryption Key Rotation Classic

To rotate secrets encryption keys on a single-server cluster:

  1. Start the K3s server with the flag --secrets-encryption

    note

    Starting K3s without encryption and enabling it at a later time is currently not supported.

  2. Prepare

    k3s secrets-encrypt prepare
  3. Kill and restart the K3s server with same arguments. If running K3s as a service:

    # If using systemd
    systemctl restart k3s
    # If using openrc
    rc-service k3s restart
  4. Rotate

    k3s secrets-encrypt rotate
  5. Kill and restart the K3s server with same arguments

  6. Reencrypt

    info

    K3s will reencrypt ~5 secrets per second.
    Clusters with large # of secrets can take several minutes to reencrypt.

    k3s secrets-encrypt reencrypt

Secrets Encryption Disable/Re-enable

After launching a server with --secrets-encryption flag, secrets encryption can be disabled.

To disable secrets encryption on a single-node cluster:

  1. Disable

    k3s secrets-encrypt disable
  2. Kill and restart the K3s server with same arguments. If running K3s as a service:

    # If using systemd
    systemctl restart k3s
    # If using openrc
    rc-service k3s restart
  3. Reencrypt with flags

    k3s secrets-encrypt reencrypt --force --skip

To re-enable secrets encryption on a single node cluster:

  1. Enable

    k3s secrets-encrypt enable
  2. Kill and restart the K3s server with same arguments

  3. Reencrypt with flags

    k3s secrets-encrypt reencrypt --force --skip

Secrets Encryption Status

The secrets-encrypt tool includes a status command that displays information about the current status of secrets encryption on the node.

An example of the command on a single-server node:

$ k3s secrets-encrypt status
Encryption Status: Enabled
Current Rotation Stage: start
Server Encryption Hashes: All hashes match

Active Key Type Name
------ -------- ----
* AES-CBC aescbckey

Another example on HA cluster, after rotating the keys, but before restarting the servers:

$ k3s secrets-encrypt status
Encryption Status: Enabled
Current Rotation Stage: rotate
Server Encryption Hashes: hash does not match between node-1 and node-2

Active Key Type Name
------ -------- ----
* AES-CBC aescbckey-2021-12-10T22:54:38Z
AES-CBC aescbckey

Details on each section are as follows:

  • Encryption Status: Displayed whether secrets encryption is disabled or enabled on the node
  • Current Rotation Stage: Indicates the current rotation stage on the node.
    Stages are: start, prepare, rotate, reencrypt_request, reencrypt_active, reencrypt_finished
  • Server Encryption Hashes: Useful for HA clusters, this indicates whether all servers are on the same stage with their local files. This can be used to identify whether a restart of servers is required before proceeding to the next stage. In the HA example above, node-1 and node-2 have different hashes, indicating that they currently do not have the same encryption configuration. Restarting the servers will sync up their configuration.
  • Key Table: Summarizes information about the secrets encryption keys found on the node.
    • Active: The "*" indicates which, if any, of the keys are currently used for secrets encryption. An active key is used by Kubernetes to encrypt any new secrets.
    • Key Type: All keys using this tool are AES-CBC type. See more info here.
    • Name: Name of the encryption key.