Policies define what a client is allowed to do inside OpenBao. Every token issued by an authentication method (OIDC, AppRole, Kubernetes, etc.) has one or more policies attached. These policies determine the exact capabilities a client has on specific paths within the tenancy namespace.

Policies are written in HCL and are the core mechanism for authorization in OpenBao.

What Policies Do

A policy controls access by specifying:

• Paths (e.g., kv/data/app/config)

• Capabilities (e.g., read, list, update, delete)

• Constraints (TTL, max TTL, etc.)

Policies do not authenticate users — they only define permissions. Authentication methods issue tokens, and tokens carry policies.

Policy Structure

A typical policy contains one or more path blocks:
Codice
 

path "kv/data/app/*" {
  capabilities = ["read", "list"]
}

path "kv/data/app/config" {
  capabilities = ["create", "update"]
}

Key elements:

• path — the secret engine path the rule applies to

• capabilities — allowed operations

• wildcards — * for multiple items, + for recursive matching

• fine‑grained rules — different capabilities for different paths

Common Capabilities

• read — retrieve a secret

• list — list keys

• create — write a new secret

• update — modify an existing secret

• delete — remove a secret

• sudo — administrative operations

Where Policies Live

Policies are stored inside the tenancy namespace under:
Codice
 

sys/policies/acl/<policy-name>

They are managed using the CLI or API.

Default policy

By default, every tenancy is provided with two policies for external secret operator mountKubernetes External Secret Operator (ESO):  Image Added

• read only for mount eso_base_ro Image Added
• read write for mount eso_base_rw Image Added

You can find these policies in the Policies section:

Image Added

Create a new policy

1. Write the policy file

Create a file named my-policy.hcl:
Codice
 

path "kv/data/myapp/*" {
  capabilities = ["read", "list"]
}

path "kv/data/myapp/config" {
  capabilities = ["create", "update"]
}

2. Upload the policy to OpenBao

Use the CLI: 

bao policy write my-policy my-policy.hcl

This creates (or updates) the policy named my-policy.

3. Verify the policy 

bao policy read my-policy

4. Attach the policy to an auth method

For example, attach it to an AppRole: 

bao auth approle role write my-role policies="my-policy"