10 KiB
OpenBao
Outline 📋
🧐 What is it?
OpenBao is a secret management tool embedded into your application stack. It can handle the creation, storage, and management of secrets, ensuring they remain secure. For seamless integration across multiple Kubernetes applications, OpenBao works with the Kubernetes External Secrets Operator, which converts OpenBao’s secrets into Kubernetes secrets.
🤔 Why do I want it?
Secure Secrets Storage
OpenBao organizes your secrets in one encrypted location, reducing the risk of loss or accidental exposure, such as through a public code push.
Controlled Access
OpenBao allows you to define rules about who can access which secrets and under what conditions.
Leasing and Revocation
Secrets with a lease are automatically revoked at the end of their lifespan. Revocation can also be done manually.
Dynamic Secrets
OpenBao generates short-lived secrets on demand and revokes them automatically when they’re no longer needed.
Encryption as a Service
OpenBao encrypts and decrypts data without storing it, offering cryptographic functions as a service.
Audit Devices and logs
Detailed logs track who accessed which secrets and when, providing complete traceability in case of a breach.
Secret Engines
OpenBao offers diverse ways to manage secrets through various secret engines. Learn more about available secret engines here.
🤿 Diving deeper
Secure Secrets Storage
OpenBao validates and authorizes clients (users, machines, applications) using tokens before granting access to secrets or sensitive data.
How does gaining access to OpenBao secrets work?
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Authentication: Before a human or machine can gain any access, an administrator must configure OpenBao with an auth method. When a client tries to log in to OpenBao, the system checks client’s data against an internal or external (see Validation below) system. Once authenticated, Vault generates an access token for the client. This token is then used for every action performed in OpenBao.
Note: the administrator can provide you with an already generated access token
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Validation: If trusted third-party credential repositories (e.g., GitHub, LDAP, AppRole) are specified, OpenBao forwards authentication to them.
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Authorization: Vault applies policies based on the authentication method and rules set by the admin to the token that was generated during authentication. Policies provide a declarative way to grant or forbid access to certain paths and operations in OpenBao.
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Access: The client uses the token for access to secrets, keys, or encryption capabilities, as per the associated policies.
If you want to read more about authentication, visit https://openbao.org/docs/concepts/auth/
Controlled Access
OpenBao uses policies to manage access to secrets. Policies are basically a combination of paths and capabilities (operations) that they allow on these path. Let’s consider this example:
path "secret/app1/password" {
capabilities = ["create", " read ", "list", "delete"]
}
path "secret/app2/* " {
capabilities = ["read", "list"]
}
This policy permits creating, reading, listing, and deleting the password at secret/app1/, but only allows reading and listing all resources in secret/app2/ and its subpaths.
Here's a tutorial how to use it.
For even deeper understanding, go to https://openbao.org/docs/concepts/policies/
Leasing and Revocation
To simplify key rolling processes, consumers using OpenBao should regularly verify their subscription status to either renew leases where permitted or request replacements for secrets that need updating. In addition to that, a lease can be revoked manually. When this happens, it invalidates that secret immediately and prevents any further renewals. OpenBao can revoke not only single secrets, but a tree of secrets, for example all secrets read by a specific user, or all secrets of a particular type.
For example: In the Kubernetes secrets engine, revoking a lease deletes associated Kubernetes service accounts, immeditally rendering their access keys invalid.
Here's a tutorial how to use it.
Dynamic Secrets
OpenBao generates temporary secrets for systems like Kubernetes, AWS, or SQL databases, only when needed. These secrets are revoked automatically after their Time-To-Live expires. For example: An application requests Kubernetes credentials from OpenBao, which generates a token with specific permissions. The token is automatically revoked after its lease ends.
Here's a tutorial how to use it.
Encryption as a Service
The transit secrets engine handles cryptographic operations on data in transit without storing it. It can encrypt, decrypt, sign, verify, and generate hashes or random bytes.
For example: Your application sends data to OpenBao for encryption before saving it to a database. OpenBao can then decrypt the data on demand, ensuring security even if the database is compromised.
Here's a tutorial how to use it.
Here you can read more about the transit secrets engine https://openbao.org/docs/secrets/transit/
Audit devices and logs
Audit devices are the tool for collecting detailed logs of all requests to OpenBao, and their responses. Because every operation with OpenBao is an API request/response, when using a single audit device, the audit log contains every interaction with the OpenBao API, including errors - except for a few paths which do not go via the audit system. Audit log telemetry on the other hand provides information on the health of your configured audit devices.
Here's a tutorial how to use it.
For more information, plese read https://openbao.org/docs/audit/ and https://openbao.org/docs/internals/telemetry/metrics/audit/
Secret Engines
One of the core concepts of OpenBao are secret engines. Think of them as a set of path-based APIs, that can be provided with some set of data, after which they take some action on that data, and they return a result. Let’s shortly take a look at all the OpenBao’s secret engines to better understand what they are.
- Key-Value secret engines – for storing key value pairs
- PKI (Public Key Infrastructure) secret engine - for certificate management
- SSH secret engine - for managing SSH credentials
- Transit secrets engine - for encrypting data without storing it
- Time-based One-Time Passwords (TOTP) secret engine - for two-factor authentication
- Kubernetes secrets engine - for seamless integration with containerized applications
Here you can find out more about secret engines https://openbao.org/docs/secrets/
How to set it up?
Note: This paragraph will be absolete in the future as the functionality will be automated.
Hint: To be able to use OpenBao it has to be unsealed first. This happens automatically. While unsealing an initial token is being created. To access this token just run the ./getpassword.sh script.
The External Secrets Operator needs a kubernetes secret containing the OpenBao's initial token (see above) to access its secrets. You can create it with:
kubectl create secret generic vault-token --from-literal=token=<root_token_from_getpassword.sh> -n openbao
To perform any actions in OpenBao you need to authenticate using the following command:
kubectl exec -ti openbao-0 -n openbao -- vault login <root_token_from_getpassword.sh>
For demontrational purposes you can enable a Key-Value secret engine on the path /data with:
kubectl exec -ti openbao-0 -n openbao -- vault secrets enable -path=data kv
And to add your first secret just run:
kubectl exec -ti openbao-0 -n openbao -- vault kv put data/postgres POSTGRES_USER=admin POSTGRES_PASSWORD=123456
To fetch it as a kubernetes secret you'll need to create an external-secrets.yaml file and apply it to the cluster with kubectl apply -f external-secrets.yaml
# external-secret.yaml
apiVersion: external-secrets.io/v1beta1
kind: ExternalSecret
metadata:
name: external-secret
namespace: openbao
spec:
refreshInterval: "15s" #This specifies the time interval at which the ExternalSecret controller will refresh the secrets.
secretStoreRef: # This references the first file.
name: bao-backend
kind: SecretStore
target: #This specifies the target Kubernetes secret that the ExternalSecret will create.
name: postgres-secret
creationPolicy: Owner
data: # This is an array of secret key-value pairs that the ExternalSecret will retrieve from the Vault secret store and store in the Kubernetes secret.
- secretKey: POSTGRES_USER #Name of the k8 secret that is being created
remoteRef: #This is an object that contains the reference to the secret in the Vault secret store.
key: data/postgres # This specifies the path to the secret in the Vault secret store
property: POSTGRES_USER #This specifies the name of the secret property to retrieve from the Vault secret.
- secretKey: POSTGRES_PASSWORD
remoteRef:
key: data/postgres
property: POSTGRES_PASSWORD
After that just run kubectl get externalsecrets -A to check that there are no problems with synchronization. And to access the secret on your cluster run: kubectl get secrets -n openbao
🔨 How to use it?
Uneasling
(Some theory)
In our stack the unsealing happens automatically. Nothing to be done here.
Controlled Access
Short tutorial here
Leasing and Revocation
Short tutorial here
Dynamic Secrets
Short tutorial here
Encryption as a Service
Short tutorial here
Audit Devices and logs
Short tutorial here