Configure Secret Storage
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You can choose the secret storage tool for Kubernetes Operator. The secret storage tool is a secure place to store sensitive information for the components that Kubernetes Operator manages. This includes secrets for MongoDB databases, Ops Manager, and AppDB.
Once you configure secret storage, Kubernetes Operator accesses the tool, retrieves the secrets, and uses them to establish connections securely.
Supported Secret Storage Tools
Kubernetes Operator supports the following secret storage tools:
Kubernetes: store sensitive information as secrets (the built-in secret storage for Kubernetes). Kubernetes secrets store authentication credentials so that only Kubernetes can access them.
HashiCorp Vault: store sensitive information in Vault, a third party service for secret management.
Secrets You Can Store
You can use any supported secret storage tool for any secret in the MongoDB Enterprise Kubernetes Operator documentation except those listed in the limitations.
Important
After configuration, Kubernetes Operator uses your selected secret storage tool for all secrets except those listed in the limitations. You can't mix and match secret storage tools.
Limitations
The following limitations exist for the supported secret storage tools:
Some registries, such as OpenShift, require imagePullSecrets to pull images from the repository. The Kubernetes Operator can't provide imagePullSecrets from HashiCorp Vault. You can specify a kubelet image credential provider to retrieve credentials for a container image registry using Kubernetes instead.
Set the Secret Storage Tool
To set the secret storage tool, select one of the following options:
To use HashiCorp Vault to store secrets for the Kubernetes Operator, complete the following procedure.
Prerequisites
Before you begin, you must:
Set up a Vault instance. The Kubernetes cluster where the Kubernetes Operator is running must have access to the Vault instance.
Note
Ensure that Vault is not running in dev mode and that your Vault installation follows any applicable configuration recommendations.
Enable Kubernetes Authentication for the Vault instance. This allows you to authenticate with Vault.
Deploy the Vault Agent sidecar injector in the Kubernetes cluster. This allows you to inject secrets from Vault into your Kubernetes Pods.
Download the four Vault policy files for the Kubernetes Operator, MongoDB database, Ops Manager, and AppDB.
Create a role in Vault with the name
mongodbenterprise
. The configuration of secrets in the Kubernetes Operator relies on the presence of this role and its exact name.
Procedure
Add the Vault policies for the Kubernetes Operator and its components.
Write the policies for Kubernetes Operator, MongoDB database, Ops Manager, and AppDB resources to Vault using the following command, replacing the variables with the values in the table:
Placeholder | Description |
---|---|
{PolicyName} | Human-readable label that identifies the policy you're creating in Vault. |
{PathToPolicyFile} | The absolute path to the policy file you downloaded. |
vault policy write {PolicyName} {PathToPolicyFile}
Repeat the command for all the resources you're adding to Vault.
Bind the Vault roles to the Vault policies for the Kubernetes Operator and its components.
Bind Vault roles to the policies for Kubernetes Operator, MongoDB database, Ops Manager, and AppDB resources using the following four commands, replacing the variables with the values in the table:
Placeholder | Description |
---|---|
{OperatorPolicyName} | A human-readable label that identifies the Kubernetes Operator policy in Vault. |
{DatabasePolicyName} | A human-readable label that identifies the MongoDB database policy in Vault. |
{OpsManagerPolicyName} | A human-readable label that identifies the Ops Manager policy in Vault. |
{AppDBPolicyName} | A human-readable label that identifies the AppDB policy in Vault. |
{ServiceAccountNamespace} | Label that identifies the namespace for the service account bound to your pod. |
vault write auth/kubernetes/role/{OperatorPolicyName} bound_service_account_names=enterprise-operator bound_service_account_namespaces={ServiceAccountNamespace}
vault write auth/kubernetes/role/{DatabasePolicyName} bound_service_account_names=mongodb-enterprise-database-pods bound_service_account_namespaces={ServiceAccountNamespace}
vault write auth/kubernetes/role/{OpsManagerPolicyName} bound_service_account_names=mongodb-enterprise-ops-manager bound_service_account_namespaces={ServiceAccountNamespace}
vault write auth/kubernetes/role/{AppDBPolicyName} bound_service_account_names=mongodb-enterprise-appdb bound_service_account_namespaces={ServiceAccountNamespace}
These commands ensure that each component's pods have only the access specified in their policy.
Note
This step grants the Kubernetes Operator access to Vault. To use Vault with applications that the Kubernetes Operator doesn't manage, you must write and bind Vault policies for those applications.
You can adapt the commands in this step to bind other policies by replacing the name of the service accounts. To configure other applications to use Vault, replace the {ServiceAccountName} in the following command with the service account used for the application's pod:
vault write auth/kubernetes/role/{PolicyName} bound_service_account_names={ServiceAccountName} bound_service_account_namespaces={ServiceAccountNamespace}
Add the annotations to the Kubernetes deployment file.
Before running commands in this step, ensure that you have
created a Vault role
with the name mongodbenterprise
.
Add the following highlighted lines to the spec.template.metadata.annotations
section of your
Kubernetes Operator deployment file. For most users, this file's name is mongodb-enterprise.yaml
or
mongodb-enterprise-openshift.yaml
.
Note
If you installed the Kubernetes Operator using Helm and set operator.vaultSecretBackend.enabled
to true
, the Kubernetes Operator adds the following annotations. You can proceed to the next step.
apiVersion: apps/v1 kind: Deployment metadata: name: mongodb-enterprise-operator namespace: production spec: replicas: 1 template: metadata: annotations: vault.hashicorp.com/agent-inject: "true" vault.hashicorp.com/role: "mongodbenterprise"
If you're running Vault in TLS mode, and specified the
operator.vaultSecretBackend.tlsSecretRef value,
the Kubernetes Operator adds the following annotations. Otherwise, add the following
highlighted line to the file, replacing {TLSSecret}
with the name of the secret
containing a ca.crt
entry. The content of the ca.crt
entry must match
the certificate of the CA used to generate the Vault TLS certificates.
annotations: vault.hashicorp.com/agent-inject: "true" vault.hashicorp.com/role: "mongodbenterprise" vault.hashicorp.com/tls-secret: {TLSSecret} vault.hashicorp.com/ca-cert: /vault/tls/ca.crt
Define the environment variable in Kubernetes.
Add the following highlighted lines to the spec.env
section of your
Kubernetes Operator deployment file. For most users, this file's name is mongodb-enterprise.yaml
or
mongodb-enterprise-openshift.yaml
.
apiVersion: apps/v1 kind: Deployment metadata: name: mongodb-enterprise-operator namespace: production spec: env: - name: OPERATOR_ENV value: ENVIRONMENT_NAME - name: SECRET_BACKEND value: VAULT_BACKEND
This defines the environment variable for Vault in Kubernetes.
Create a file with the Vault configuration information.
Using your preferred text editing application, create a file named config
.
Paste the following text into the file:
apiVersion: v1 kind: ConfigMap metadata: name: secret-configuration namespace: {Namespace} data: VAULT_SERVER_ADDRESS: {VaultServerAddress} OPERATOR_SECRET_BASE_PATH: mongodbenterprise/operator DATABASE_SECRET_BASE_PATH: mongodbenterprise/database OPS_MANAGER_SECRET_BASE_PATH: mongodbenterprise/opsmanager APPDB_SECRET_BASE_PATH: mongodbenterprise/appdb
The paths in this file are the default paths. You can replace them with your base paths if you customized your Kubernetes Operator configuration.
If you're running Vault in TLS mode, you must also add the following highlighted line to the file:
OPS_MANAGER_SECRET_BASE_PATH: mongodbenterprise/opsmanager APPDB_SECRET_BASE_PATH: mongodbenterprise/appdb TLS_SECRET_REF: {TLSSecret}
Replace the placeholders in the Vault configuration information.
Replace the placeholders in the config
file with these values. Save
the file with a YAML file type by replacing the .txt
file extension with
.yaml
.
Placeholder | Description |
---|---|
{Namespace} | The namespace you created
for the Kubernetes Operator. The default namespace is mongodb . |
{VaultServerAddress} | The address that the Kubernetes Operator should use to connect to
Vault. |
{TLSSecret} | Name of a secret containing a ca.crt entry. The content of the
ca.crt entry must match the certificate of the CA used to generate
the Vault TLS certificates. |
Create a ConfigMap with the Vault configuration.
Issue the following command to create a ConfigMap containing the Vault information:
kubectl create configmap secret-configuration --from-file=config.yaml
This creates a ConfigMap named secret-configuration
. This
ConfigMap contains the contents of the config
file.
Manually migrate secrets that don't migrate automatically
You must manually migrate the following secrets to store them in Vault:
Any existing user-created secrets, including Operator credentials stored as Kubernetes secrets, if applicable
The gen-key secret Kubernetes Operator creates
The Ops Manager admin credentials/admin key Kubernetes Operator creates
TLS secrets
To manually migrate or create new secrets, add them to Vault. After you add them to Vault, you can remove them from Kubernetes.
All other secrets that the Kubernetes Operator creates migrate automatically, and Kubernetes Operator uses Vault for new secrets. User-created secrets must be added to Vault.
Note
cert-manager automatically recreates the Kubernetes secrets that it generates if you delete them from Kubernetes. You must manually manage the removal of these secrets or stop using cert-manager to avoid storing the secrets in Kubernetes.
Next Steps
After you configure the secret storage tool for the MongoDB Enterprise Kubernetes Operator, you can:
Read the Considerations.
Complete the Prerequisites.