---
layout: docs
page_title: Key Management
description: Learn about the key management in Nomad.
---

# Key Management

Nomad servers maintain an encryption keyring used to encrypt [Variables][],
sign task [workload identities][], and sign OIDC [client assertion JWTs][].
The servers encrypt these data encryption keys (DEK) and store the wrapped keys
in Raft.

The key encryption key (KEK) used to encrypt the DEK is controlled by the
[`keyring`][] provider. When using an external KMS or Vault transit encryption
provider, the KEK is securely stored outside of Nomad. For the default AEAD
provider, the KEK is stored in cleartext in Raft.

<Note>

Default AEAD provider users should be aware that storing the Key Encryption Key
(KEK) in cleartext in Raft may expose data in case of a breach.

</Note>

Under normal operations the keyring is entirely managed by Nomad, but this
section provides administrators additional context around key replication and
recovery.

## Key Rotation

Only one key in the keyring is "active" at any given time, and all encryption
and signing operations happen on the leader. Nomad automatically rotates the
active encryption key every 30 days. When a key is rotated, the existing keys
are marked as "inactive" but not deleted, so they can be used for decrypting
previously encrypted variables and verifying workload identities for existing
allocations.

If you believe key material has been compromised, you can execute [`nomad
operator root keyring rotate -full`][]. A new "active" key will be created and
"inactive" keys will be marked "rekeying". Nomad will asynchronously decrypt and
re-encrypt all variables with the new key. As each key's variables are encrypted
with the new key, the old key will marked as "deprecated".

## Key Decryption

When a leader is elected, the leader creates the keyring if it does not already
exist. When a key is added, the new wrapped key material is replicated via
Raft. As each server replicates the new key, the server starts a task to decrypt
the key material. Until this task completes, the server is not able to serve
requests that require this key.

## Key Redaction in Raft Snapshots

The default AEAD `keyring` configuration stores the KEK in Raft. Raft snapshots
contain the cleartext KEK. The `nomad operator snapshot save` command has a
`-redact` option that removes the key material when creating a snapshot. The
`nomad operator snapshot redact` command removes key material from an
existing snapshot.

Redacting key material is not required when using an external KMS.

## Legacy Keystore

Versions of Nomad prior to 1.9.0 stored only key metadata in Raft, but the
encryption key material was stored in a separate file in the `keystore`
subdirectory of the Nomad [data directory][]. These files have the extension
`.nks.json`. The key material in each file is wrapped in a unique key encryption
key (KEK) that is not shared between servers.

Each server runs a key replication process that watches for changes to the state
store and fetches the key material from the leader asynchronously, falling
back to retrieving from other servers in the case where a key is written
immediately before a leader election. Nomad 1.9.0 and above can replicate keys
from older servers.

However, replicating keys from older servers means that to restore an older cluster from snapshot you need to
also provide the keystore directory with the `.nks.json` key files on at least
one server. The `.nks.json` key files are unique per server, but only one
server's key files are needed to recover the cluster. Operators should continue
to include these files as part of your organization's backup and recovery
strategy for the cluster until the cluster is fully upgraded to Nomad 1.9.0 and
at least one [`root_key_gc_interval`][] has passed.

If you are recovering an older Raft snapshot onto a new cluster without running
workloads, you can skip restoring the keyring and run [`nomad operator root
keyring rotate`][] once the servers have joined.



[variables]: /nomad/docs/concepts/variables
[workload identities]: /nomad/docs/concepts/workload-identity
[client assertion JWTs]: /nomad/docs/concepts/acl/auth-methods/oidc#client-assertions
[data directory]: /nomad/docs/configuration#data_dir
[`keyring`]: /nomad/docs/configuration/keyring
[`nomad operator root keyring rotate -full`]: /nomad/docs/commands/operator/root/keyring-rotate
[`nomad operator root keyring rotate`]: /nomad/docs/commands/operator/root/keyring-rotate
[`root_key_gc_interval`]: /nomad/docs/configuration/server#root_key_gc_interval
