New to KubeVault? Please start here.

Use a Vault Server with Multiple Kubernetes Clusters

In this tutorial, we are going to show how to use KubeVault operators in multiple Kubernetes clusters against a shared Vault server.

To being with, we have created two GKE clusters.

cluster image

We are going to install KubeVault operator in demo-cluster-1 using Helm 3. We are going to set --cluster-name flag. This flag value will be used by KubeVault operator when creating resources in Vault.

$ kubectl config current-context
gke_ackube_us-central1-a_demo-cluster-1

$ helm install vault-operator appscode/vault-operator \
  --version v2022.09.22 \
  --namespace kube-system \
  --set clusterName=demo-cluster-1

$ kubectl get pods -n kube-system
NAME                                                       READY   STATUS    RESTARTS   AGE
vault-operator-5fc7666575-8v6ft                            1/1     Running   0          1h

We are going to deploy Vault in demo-cluster-1 using KubeVault operator. Guides to deploy Vault in GKE can be found here.

$ kubectl get vaultserverversions/1.2.0 -o yaml
apiVersion: catalog.kubevault.com/v1alpha1
kind: VaultServerVersion
metadata:
  name: 1.2.0
spec:
  version: 1.2.0
  deprecated: false
  vault:
    image: vault:1.2.0
  unsealer:
    image: kubevault/vault-unsealer:v0.3.0
  exporter:
    image: kubevault/vault-exporter:0.1.0

$ cat examples/guides/provider/multi-cluster/my-vault.yaml
cat examples/guides/provider/multi-cluster/my-vault.yaml
apiVersion: kubevault.com/v1alpha1
kind: VaultServer
metadata:
  name: my-vault
  namespace: demo
spec:
  replicas: 1
  version: "1.2.0"
  backend:
    gcs:
      bucket: "demo-vault"
      credentialSecret: "google-cred"
  serviceTemplate:
    spec:
      type: LoadBalancer
      loadBalancerIP: 104.155.177.205
  tls:
    caBundle: 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
    tlsSecret: vault-tls
  unsealer:
    secretShares: 4
    secretThreshold: 2
    mode:
      googleKmsGcs:
        bucket: "demo-vault"
        kmsProject: "ackube"
        kmsLocation: "global"
        kmsKeyRing: "vault"
        kmsCryptoKey: "vault-key"
        credentialSecret: "google-cred"

$ kubectl apply -f docs/examples/guides/provider/multi-cluster/my-vault.yaml
vaultserver.kubevault.com/my-vault created

$ kubectl get vaultserver my-vault -n demo
NAME       NODES   VERSION   STATUS    AGE
my-vault   1       1.2.0     Running   1m

$ kubectl get services -n demo
NAME       TYPE           CLUSTER-IP     EXTERNAL-IP       PORT(S)                                        AGE
my-vault   LoadBalancer   10.3.251.241   104.155.177.205   8200:31542/TCP,8201:31390/TCP,9102:30911/TCP   2m

Now we are going to create demo-policy-secret-admin VaultPolicy in demo-cluster-1. Guides to manage policy in Vault can be found here.

$ cat examples/guides/provider/multi-cluster/demo-policy-secret-admin.yaml
apiVersion: policy.kubevault.com/v1alpha1
kind: VaultPolicy
metadata:
  name: demo-policy-secret-admin
  namespace: demo
spec:
  ref:
    name: my-vault
    namespace: demo
  policyDocument: |
    path "secret/*" {
      capabilities = ["create", "read", "update", "delete", "list"]
    }
$ kubectl apply -f docs/examples/guides/provider/multi-cluster/demo-policy-secret-admin.yaml
vaultpolicy.policy.kubevault.com/demo-policy-secret-admin created

$ kubectl get vaultpolicies -n demo
NAME                              STATUS    AGE
demo-policy-secret-admin          Success   1m

Check the created demo-policy-secret-admin VaultPolicy in Vault. To resolve the naming conflict, name of policy in Vault will follow this format: k8s.{clusterName}.{metadata.namespace}.{metadata.name}. For this case, it is k8s.demo-cluster-1.demo.demo-policy-secret-admin.

$ export VAULT_ADDR='https://104.155.177.205:31542'

$ export VAULT_CACERT="cert/ca.crt"

$ export VAULT_TOKEN="s.KLJFDIUJLKDFDLKFJ"

$ vault policy list
default
k8s.demo-cluster-1.demo.demo-policy-secret-admin
my-vault-policy-controller
root

We are going to install KubeVault operator in demo-cluster-2 using Helm 3. We are going to set --cluster-name, this flag value will be used by KubeVault operator when creating resource in Vault.

$ kubectl config current-context
gke_ackube_us-central1-a_demo-cluster-2

$ helm install vault-operator appscode/vault-operator \
  --version v2022.09.22 \
  --namespace kube-system \
  --set clusterName=demo-cluster-2

$ kubectl get pods -n kube-system
NAME                                                       READY   STATUS    RESTARTS   AGE
vault-operator-5fc7666575-8v6ft                            1/1     Running   0          1h

Now we are going to create an AppBinding that contains connection and credential information of the Vault that is deployed in demo-cluster-1. In this AppBinding, we are going to use token auth. Guides to Vault authentication using AppBinding can be found here.

$ cat examples/guides/provider/multi-cluster/vault-app.yaml
apiVersion: appcatalog.appscode.com/v1alpha1
kind: AppBinding
metadata:
  name: vault-app
  namespace: demo
spec:
  secret:
    name: vault-token
  clientConfig:
    caBundle: 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
    url: https://104.155.177.205:8200

$ kubectl apply -f docs/examples/guides/provider/multi-cluster/vault-app.yaml
appbinding.appcatalog.appscode.com/vault-app created

Now we are going to create demo-policy-secret-reader VaultPolicy in demo-cluster-2.

$ cat examples/guides/provider/multi-cluster/demo-policy-secret-reader.yaml
apiVersion: policy.kubevault.com/v1alpha1
kind: VaultPolicy
metadata:
  name: demo-policy-secret-reader
  namespace: demo
spec:
  ref:
    name: vault-app
    namespace: demo
  policyDocument: |
    path "secret/*" {
      capabilities = ["read", "list"]
    }

$ kubectl apply -f docs/examples/guides/provider/multi-cluster/demo-policy-secret-reader.yaml
vaultpolicy.policy.kubevault.com/demo-policy-secret-reader created

$ kubectl get vaultpolicies -n demo
NAME                        STATUS    AGE
demo-policy-secret-reader   Success   1m

Check the created demo-policy-secret-reader VaultPolicy in Vault. To resolve the naming conflict, name of policy in Vault will follow this format: k8s.{clusterName}.{metadata.namespace}.{metadata.name}. For this case, it is k8s.demo-cluster-2.demo.demo-policy-secret-reader.

$ vault policy list
default
k8s.demo-cluster-1.demo.demo-policy-secret-admin
k8s.demo-cluster-2.demo.demo-policy-secret-reader
my-vault-policy-controller
root

This how we can use KubeVault operator in multiple Kubernetes clusters with a shared Vault Server without naming conflict.