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Run OpenBao on Kubernetes

OpenBao works with Kubernetes in various modes: dev, standalone, ha, and external.

warning

Important Note: This chart is not compatible with Helm 2. Please use Helm 3.6+ with this chart.

Helm chart​

The OpenBao Helm chart is the recommended way to install and configure OpenBao on Kubernetes. In addition to running OpenBao itself, the Helm chart is the primary method for installing and configuring OpenBao to integrate with other services such as Consul for High Availability (HA) deployments.

While the Helm chart automatically sets up complex resources and exposes the configuration to meet your requirements, it does not automatically operate OpenBao. You are still responsible for learning how to monitor, backup, upgrade, etc. the OpenBao cluster.

warning

Security Warning: By default, the chart runs in standalone mode. This mode uses a single OpenBao server with a file storage backend. This is a less secure and less resilient installation that is NOT appropriate for a production setup. It is highly recommended to use a properly secured Kubernetes cluster, learn the available configuration options, and read the production deployment checklist.

How-To​

Install OpenBao​

Helm must be installed and configured on your machine. Please refer to the Helm documentation for more information.

To use the Helm chart, add the Hashicorp helm repository and check that you have access to the chart:

$ helm repo add openbao https://openbao.github.io/openbao-helm
"openbao" has been added to your repositories

$ helm search repo openbao/openbao
NAME            CHART VERSION   APP VERSION             DESCRIPTION
openbao/openbao 0.4.0           v2.0.0-alpha20240329    Official OpenBao Chart
info

Important: The Helm chart is new and under significant development. Please always run Helm with --dry-run before any install or upgrade to verify changes.

Use helm install to install the latest release of the OpenBao Helm chart.

$ helm install openbao openbao/openbao

Or install a specific version of the chart.

# List the available releases
$ helm search repo openbao/openbao -l
NAME            CHART VERSION   APP VERSION             DESCRIPTION
openbao/openbao 0.4.0           v2.0.0-alpha20240329    Official OpenBao Chart
openbao/openbao 0.3.0           v2.0.0-alpha20240329    Official OpenBao Chart
openbao/openbao 0.2.0           v2.0.0-alpha20240329    Official OpenBao Chart
...

# Install version 0.4.0
$ helm install openbao openbao/openbao --version 0.4.0

The helm install command accepts parameters to override default configuration values inline or defined in a file.

Override the server.dev.enabled configuration value:

$ helm install openbao openbao/openbao \
    --set "server.dev.enabled=true"

Override all the configuration found in a file:

$ cat override-values.yml
server:
  ha:
    enabled: true
    replicas: 5
##
$ helm install openbao openbao/openbao \
    --values override-values.yml

Dev mode​

The Helm chart may run a OpenBao server in development. This installs a single OpenBao server with a memory storage backend.

info

Dev mode: This is ideal for learning and demonstration environments but NOT recommended for a production environment.

Install the latest OpenBao Helm chart in development mode.

$ helm install openbao openbao/openbao \
    --set "server.dev.enabled=true"

Standalone mode​

The Helm chart defaults to run in standalone mode. This installs a single OpenBao server with a file storage backend.

Install the latest OpenBao Helm chart in standalone mode.

$ helm install openbao openbao/openbao

HA mode​

The Helm chart may be run in high availability (HA) mode. This installs three OpenBao servers with an existing integrated storage backend. Install the latest OpenBao Helm chart in HA mode.

$ helm install openbao openbao/openbao \
    --set "server.ha.enabled=true"

External mode​

The Helm chart may be run in external mode. This installs no OpenBao server and relies on a network addressable OpenBao server to exist.

Install the latest OpenBao Helm chart in external mode.

$ helm install openbao openbao/openbao \
    --set "injector.externalVaultAddr=http://external-openbao:8200"

View the OpenBao UI​

The OpenBao UI is enabled but NOT exposed as service for security reasons. The OpenBao UI can also be exposed via port-forwarding or through a ui configuration value.

Expose the OpenBao UI with port-forwarding:

$ kubectl port-forward openbao-0 8200:8200
Forwarding from 127.0.0.1:8200 -> 8200
Forwarding from [::1]:8200 -> 8200
##...

Initialize and unseal OpenBao​

After the OpenBao Helm chart is installed in standalone or ha mode one of the OpenBao servers need to be initialized. The initialization generates the credentials necessary to unseal all the OpenBao servers.

CLI initialize and unseal​

View all the OpenBao pods in the current namespace:

$ kubectl get pods -l app.kubernetes.io/name=openbao
NAME                                    READY   STATUS    RESTARTS   AGE
openbao-0                                 0/1     Running   0          1m49s
openbao-1                                 0/1     Running   0          1m49s
openbao-2                                 0/1     Running   0          1m49s

Initialize one OpenBao server with the default number of key shares and default key threshold:

$ kubectl exec -ti openbao-0 -- bao operator init
Unseal Key 1: MBFSDepD9E6whREc6Dj+k3pMaKJ6cCnCUWcySJQymObb
Unseal Key 2: zQj4v22k9ixegS+94HJwmIaWLBL3nZHe1i+b/wHz25fr
Unseal Key 3: 7dbPPeeGGW3SmeBFFo04peCKkXFuuyKc8b2DuntA4VU5
Unseal Key 4: tLt+ME7Z7hYUATfWnuQdfCEgnKA2L173dptAwfmenCdf
Unseal Key 5: vYt9bxLr0+OzJ8m7c7cNMFj7nvdLljj0xWRbpLezFAI9

Initial Root Token: s.zJNwZlRrqISjyBHFMiEca6GF
##...

The output displays the key shares and initial root key generated.

Unseal the OpenBao server with the key shares until the key threshold is met:

## Unseal the first openbao server until it reaches the key threshold
$ kubectl exec -ti openbao-0 -- bao operator unseal # ... Unseal Key 1
$ kubectl exec -ti openbao-0 -- bao operator unseal # ... Unseal Key 2
$ kubectl exec -ti openbao-0 -- bao operator unseal # ... Unseal Key 3

Repeat the unseal process for all OpenBao server pods. When all OpenBao server pods are unsealed they report READY 1/1.

$ kubectl get pods -l app.kubernetes.io/name=openbao
NAME                                    READY   STATUS    RESTARTS   AGE
openbao-0                                 1/1     Running   0          1m49s
openbao-1                                 1/1     Running   0          1m49s
openbao-2                                 1/1     Running   0          1m49s

Google KMS auto unseal​

The Helm chart may be run with Google KMS for Auto Unseal. This enables OpenBao server pods to auto unseal if they are rescheduled.

OpenBao Helm requires the Google Cloud KMS credentials stored in credentials.json and mounted as a secret in each OpenBao server pod.

Create the secret​

First, create the secret in Kubernetes:

kubectl create secret generic kms-creds --from-file=credentials.json

OpenBao Helm mounts this to /openbao/userconfig/kms-creds/credentials.json.

Config example​

This is a OpenBao Helm configuration that uses Google KMS:

global:
  enabled: true

server:
  extraEnvironmentVars:
    GOOGLE_REGION: global
    GOOGLE_PROJECT: <PROJECT NAME>
    GOOGLE_APPLICATION_CREDENTIALS: /openbao/userconfig/kms-creds/credentials.json

  volumes:
    - name: userconfig-kms-creds
      secret:
        defaultMode: 420
        secretName: kms-creds

  volumeMounts:
    - mountPath: /openbao/userconfig/kms-creds
      name: userconfig-kms-creds
      readOnly: true

  ha:
    enabled: true
    replicas: 3

    config: |
      ui = true

      listener "tcp" {
        tls_disable = 1
        address = "[::]:8200"
        cluster_address = "[::]:8201"
      }

      seal "gcpckms" {
        project     = "<NAME OF PROJECT>"
        region      = "global"
        key_ring    = "<NAME OF KEYRING>"
        crypto_key  = "<NAME OF KEY>"
      }

Amazon KMS auto unseal​

The Helm chart may be run with AWS KMS for Auto Unseal. This enables OpenBao server pods to auto unseal if they are rescheduled.

OpenBao Helm requires the AWS credentials stored as environment variables that are defined in each OpenBao server pod.

Create the secret​

First, create a secret with your KMS access key/secret:

$ kubectl create secret generic kms-creds \
    --from-literal=AWS_ACCESS_KEY_ID="${AWS_ACCESS_KEY_ID?}" \
    --from-literal=AWS_SECRET_ACCESS_KEY="${AWS_SECRET_ACCESS_KEY?}"
Config example​

This is a OpenBao Helm configuration that uses AWS KMS:

global:
  enabled: true

server:
  extraSecretEnvironmentVars:
    - envName: AWS_ACCESS_KEY_ID
      secretName: kms-creds
      secretKey: AWS_ACCESS_KEY_ID
    - envName: AWS_SECRET_ACCESS_KEY
      secretName: kms-creds
      secretKey: AWS_SECRET_ACCESS_KEY

  ha:
    enabled: true
    config: |
      ui = true

      listener "tcp" {
        tls_disable = 1
        address = "[::]:8200"
        cluster_address = "[::]:8201"
      }

      seal "awskms" {
        region     = "KMS_REGION_HERE"
        kms_key_id = "KMS_KEY_ID_HERE"
      }

Probes​

Probes are essential for detecting failures, rescheduling and using pods in Kubernetes. The helm chart offers configurable readiness and liveliness probes which can be customized for a variety of use cases.

OpenBao's /sys/health` endpoint can be customized to change the behavior of the health check. For example, we can change the OpenBao readiness probe to show the OpenBao pods are ready even if they're still uninitialized and sealed using the following probe:

server:
  readinessProbe:
    enabled: true
    path: '/v1/sys/health?standbyok=true&sealedcode=204&uninitcode=204'

Using this customized probe, a postStart script could automatically run once the pod is ready for additional setup.

Upgrading OpenBao on kubernetes​

To upgrade OpenBao on Kubernetes, we follow the same pattern as generally upgrading OpenBao, except we can use the Helm chart to update the OpenBao server StatefulSet. It is important to understand how to generally upgrade OpenBao before reading this section.

The OpenBao StatefulSet uses OnDelete update strategy. It is critical to use OnDelete instead of RollingUpdate because standbys must be updated before the active primary. A failover to an older version of OpenBao must always be avoided.

danger

IMPORTANT NOTE: Always back up your data before upgrading! OpenBao does not make backward-compatibility guarantees for its data store. Simply replacing the newly-installed OpenBao binary with the previous version may not cleanly downgrade OpenBao, as upgrades may perform changes to the underlying data structure that make the data incompatible with a downgrade. If you need to roll back to a previous version of OpenBao, you should roll back your data store as well.

Upgrading OpenBao servers​

danger

IMPORTANT NOTE: Helm will install the latest chart found in a repo by default. It's recommended to specify the chart version when upgrading.

To initiate the upgrade, set the server.image values to the desired OpenBao version, either in a values yaml file or on the command line. For illustrative purposes, the example below uses openbao:123.456.

server:
  image:
    repository: 'openbao'
    tag: '123.456'

Next, list the Helm versions and choose the desired version to install.

$ helm search repo openbao/openbao                            
NAME            CHART VERSION   APP VERSION             DESCRIPTION           
openbao/openbao 0.4.0           v2.0.0-alpha20240329    Official OpenBao Chart

Next, test the upgrade with --dry-run first to verify the changes sent to the Kubernetes cluster.

$ helm upgrade openbao openbao/openbao --version=0.4.0 \
    --set='server.image.repository=openbao' \
    --set='server.image.tag=123.456' \
    --dry-run

This should cause no changes (although the resources are updated). If everything is stable, helm upgrade can be run.

The helm upgrade command should have updated the StatefulSet template for the OpenBao servers, however, no pods have been deleted. The pods must be manually deleted to upgrade. Deleting the pods does not delete any persisted data.

If OpenBao is not deployed using ha mode, the single OpenBao server may be deleted by running:

$ kubectl delete pod <name of OpenBao pod>

If OpenBao is deployed using ha mode, the standby pods must be upgraded first. OpenBao has K8s service discovery built in (when enabled in the server configuration) and will automatically change the labels of the pod with its current leader status. These labels can be used to filter the pods.

For example, select all pods that are OpenBao standbys:

$ kubectl get pods -l openbao-active=false

Select the active OpenBao pod:

$ kubectl get pods -l openbao-active=true

Next, sequentially delete every pod that is not the active primary, ensuring the quorum is maintained at all times:

$ kubectl delete pod <name of OpenBao pod>

If auto-unseal is not being used, the newly scheduled OpenBao standby pods needs to be unsealed:

$ kubectl exec -ti <name of pod> -- bao operator unseal

Finally, once the standby nodes have been updated and unsealed, delete the active primary:

$ kubectl delete pod <name of OpenBao primary>

Similar to the standby nodes, the former primary also needs to be unsealed:

$ kubectl exec -ti <name of pod> -- bao operator unseal

After a few moments the OpenBao cluster should elect a new active primary. The OpenBao cluster is now upgraded!

Protecting sensitive OpenBao configurations​

OpenBao Helm renders a OpenBao configuration file during installation and stores the file in a Kubernetes configmap. Some configurations require sensitive data to be included in the configuration file and would not be encrypted at rest once created in Kubernetes.

The following example shows how to add extra configuration files to OpenBao Helm to protect sensitive configurations from being in plaintext at rest using Kubernetes secrets.

First, create a partial OpenBao configuration with the sensitive settings OpenBao loads during startup:

$ cat <<EOF >>config.hcl
storage "mysql" {
username = "user1234"
password = "secret123!"
database = "openbao"
}
EOF

Next, create a Kubernetes secret containing this partial configuration:

$ kubectl create secret generic openbao-storage-config \
    --from-file=config.hcl

Finally, mount this secret as an extra volume and add an additional -config flag to the OpenBao startup command:

$ helm install openbao openbao/openbao \
  --set='server.volumes[0].name=userconfig-openbao-storage-config' \
  --set='server.volumes[0].secret.defaultMode=420' \
  --set='server.volumes[0].secret.secretName=openbao-storage-config' \
  --set='server.volumeMounts[0].mountPath=/openbao/userconfig/openbao-storage-config' \
  --set='server.volumeMounts[0].name=userconfig-openbao-storage-config' \
  --set='server.volumeMounts[0].readOnly=true' \
  --set='server.extraArgs=-config=/openbao/userconfig/openbao-storage-config/config.hcl'

Architecture​

We recommend running OpenBao on Kubernetes with the same general architecture as running it anywhere else. There are some benefits Kubernetes can provide that eases operating a OpenBao cluster and we document those below.

Production deployment checklist​

End-to-End TLS. OpenBao should always be used with TLS in production. If intermediate load balancers or reverse proxies are used to front OpenBao, they should not terminate TLS. This way traffic is always encrypted in transit to OpenBao and minimizes risks introduced by intermediate layers.

Single Tenancy. OpenBao should be the only main process running on a machine. This reduces the risk that another process running on the same machine is compromised and can interact with OpenBao. This can be accomplished by using OpenBao Helm's affinity configurable.

Enable Auditing. OpenBao supports several auditing backends. Enabling auditing provides a history of all operations performed by OpenBao and provides a forensics trail in the case of misuse or compromise. Audit logs securely hash any sensitive data, but access should still be restricted to prevent any unintended disclosures. OpenBao Helm includes a configurable auditStorage option that provisions a persistent volume to store audit logs.

Immutable Upgrades. OpenBao relies on an external storage backend for persistence, and this decoupling allows the servers running OpenBao to be managed immutably. When upgrading to new versions, new servers with the upgraded version of OpenBao are brought online. They are attached to the same shared storage backend and unsealed. Then the old servers are destroyed. This reduces the need for remote access and upgrade orchestration which may introduce security gaps. See the upgrade section for instructions on upgrading OpenBao on Kubernetes.

Upgrade Frequently. OpenBao is actively developed, and updating frequently is important to incorporate security fixes and any changes in default settings such as key lengths or cipher suites. Subscribe to the OpenBao mailing list and GitHub CHANGELOG for updates.

Restrict Storage Access. OpenBao encrypts all data at rest, regardless of which storage backend is used. Although the data is encrypted, an attacker with arbitrary control can cause data corruption or loss by modifying or deleting keys. Access to the storage backend should be restricted to only OpenBao to avoid unauthorized access or operations.