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Getting Started

Secrets Engines

Previously, we saw how to read and write arbitrary secrets to Vault. You may have noticed all requests started with secret/. Try the following command which will result an error:

$ vault kv put foo/bar a=b

Error making API request.

URL: GET http://localhost:8200/v1/sys/internal/ui/mounts/foo/bar
Code: 403. Errors:

* preflight capability check returned 403, ... grant access to path "foo/bar/"

The path prefix tells Vault which secrets engine to which it should route traffic. When a request comes to Vault, it matches the initial path part using a longest prefix match and then passes the request to the corresponding secrets engine enabled at that path. Vault presents these secrets engines similar to a filesystem.

By default, Vault enables a secrets engine called kv at the path secret/. The kv secrets engine reads and writes raw data to the backend storage. Vault supports many other secrets engines besides kv, and this feature makes Vault flexible and unique.

This page discusses secrets engines and the operations they support. This information is important to both operators who will configure Vault and users who will interact with Vault.

Enable a Secrets Engine

To get started, enable another instance of the kv secrets engine at a different path. Each path is completely isolated and cannot talk to other paths. For example, a kv secrets engine enabled at foo has no ability to communicate with a kv secrets engine enabled at bar.

$ vault secrets enable -path=kv kv

Success! Enabled the kv secrets engine at: kv/

The path where the secrets engine is enabled defaults to the name of the secrets engine. Thus, the following commands are actually equivalent:

$ vault secrets enable -path=kv kv

$ vault secrets enable kv

To verify our success and get more information about the secrets engine, use the vault secrets list command:

$ vault secrets list

Path          Type         Accessor              Description
----          ----         --------              -----------
cubbyhole/    cubbyhole    cubbyhole_78189996    per-token private secret storage
identity/     identity     identity_ac07951e     identity store
kv/           kv           kv_15087625           n/a
secret/       kv           kv_4b990c45           key/value secret storage
sys/          system       system_adff0898       system endpoints used for control, policy and debugging

This shows there are 4 enabled secrets engines on this Vault server. You can see the type of the secrets engine, the corresponding path, and an optional description (or "n/a" if none was given).

Take a few moments to read and write some data to the new kv secrets engine enabled at kv/. Here are a few ideas to get started:

$ vault kv put kv/hello target=world

$ vault kv get kv/hello

$ vault kv put kv/my-secret value="s3c(eT"

$ vault kv get kv/my-secret

$ vault kv delete kv/my-secret

$ vault kv list kv/

Disable a Secrets Engine

When a secrets engine is no longer needed, it can be disabled. When a secrets engine is disabled, all secrets are revoked and the corresponding Vault data and configuration is removed.

$ vault secrets disable kv/

Success! Disabled the secrets engine (if it existed) at: kv/

Note that this command takes a PATH to the secrets engine as an argument, not the TYPE of the secrets engine.

Any requests to route data to the original path would result in an error, but another secrets engine could now be enabled at that path.

What is a Secrets Engine?

Now that you've successfully enabled and disabled a secrets engine... what is it? What is the point of a secrets engine?

As mentioned above, Vault behaves similarly to a virtual filesystem. The read/write/delete/list operations are forwarded to the corresponding secrets engine, and the secrets engine decides how to react to those operations.

This abstraction is incredibly powerful. It enables Vault to interface directly with physical systems, databases, HSMs, etc. But in addition to these physical systems, Vault can interact with more unique environments like AWS IAM, dynamic SQL user creation, etc. all while using the same read/write interface.


You now know about secrets engines and how to operate on them. This is important knowledge to move forward and learn about other secrets engines.