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 Key/Value version2 secrets
kv-v2) at the
secret/ when running in
dev mode. The key/value secrets engine reads
and writes raw data to the backend storage. Vault supports many other secrets
engines, and this feature makes Vault flexible and unique.
NOTE: The key/value secrets engine has two versions:
kv (version 1) and
kv-v2 (version 2). The
kv-v2 is versioned
kv secrets engine which can
retain a number of secrets versions.
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 the
kv secrets engine. 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
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 command is equivalent to executing the above command.
vault secrets enable kv
Executing this command will throw the
path is already in use at kv/ error.
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).
sys/ path corresponds to the system backend. These paths interact with
Vault's core system and are not required for beginners.
Take a few moments to read and write some data to the new
kv secrets engine
kv/. Here are a few ideas to get started.
To create secrets, use the
kv put command.
vault kv put kv/hello target=world Success! Data written to: kv/hello
To read the secrets stored in the
kv/hello path, use the
kv get command.
vault kv get kv/hello ===== Data ===== Key Value --- ----- target world
Creat secrets at the
vault kv put kv/my-secret value="s3c(eT" Success! Data written to: kv/my-secret
Read the secrets at
vault kv get kv/my-secret ==== Data ==== Key Value --- ----- value s3c(eT
Delete the secrets at
vault kv delete kv/my-secret Success! Data deleted (if it existed) at: kv/my-secret
List existing keys at the
vault kv list kv/ Keys ---- hello
»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.