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HashiCorp Vault

HashiCorp Vault is a tool for securely managing secrets. A secret is anything that you want to tightly control access to, such as API keys, passwords, or certificates. Vault provides a unified interface to any secret, while providing tight access control and recording a detailed audit log.

When you create a secret in Kubernetes it is stored in etcd as plain text, and the secret is also accessible to anyone that has access to your cluster. Vault solves this issue by providing a central secret management store that provides an additional layer of security using its authentication methods. Secrets are only accessible when you provide a corresponding authentication token.

There are two kinds of secrets stored in Vault for SAAP:

  • Secrets for managed applications provided by Stakater, such as Nexus repository credential:
    • Users only have read permissions
    • The Vault path is managed-addons/*
  • Tenant specific secrets:
    • A KV v2 secret engine is enabled on the TENANT_NAME/kv path by default
    • Users can enable/disable secret engines on TENANT_NAME/* paths and create/delete/update/read secrets through them

Users can manage secrets via Vault UI or Vault CLI.

Manage Vault secrets via UI

Users included in any tenants can access the Vault UI using OIDC authentication.

Once logged in, users can do all actions on the path TENANT_NAME/*:

  • Enable/disable any kinds of secret engines
  • Create/update/get/list/delete secrets

Authentication

To log in to Vault via the UI:

  1. Access Vault via Forecastle or https://stakater-vault-openshift-stakater-vault.CLUSTER_DOMAIN
  2. Select the OIDC method
  3. Keep Role as Default
  4. Click Sign in with OIDC Provider:

    Vault-oidc-login

  5. A login dialogue will pop up. The browser needs to allow popup dialogues:

    Vault-login_popup

Enable secret engines

To enable a secrets engine:

  1. Click on the Secrets tab

  2. Under Secrets Engines, select Enable new engine:

    select-secret-engine

  3. Select an engine and click next:

    configure-secret-engine

Create secrets

To create a secret:

  1. Click on your TENANT/kv path
  2. Click on the Create Secret button:

    create-secret

  3. Provide key-value pair to add secret:

    create-secret

Manage Vault secrets via CLI

To use the Vault CLI, a token is required. Users can get/renew/revoke a token from the UI:

  1. Click on the user account:

    Vault-token

  2. Once a token is fetched, users can use the terminal provided by the UI, so there is no need to install the Vault CLI:

    Vault-CLI

  3. If using the Vault CLI, login with the token:

    vault login token=${TOKEN}
    

Consume Vault secrets

SAAP supports 3 different ways to consume secrets from Vault:

  • Option 1 (Recommended): Consume Vault secret via ExternalSecret
  • Option 2: Consume Vault secret via a Volume
  • Option 3: Consume Vault secret via Environment Variable

Below you can find step-by-step guides to consume secrets via the different options.

Option 1: Consume Vault secret via ExternalSecret

Kubernetes secret by default do not support storing or retrieving secret data from external secret management systems such as Vault. External Secrets solves this problem by providing access to secrets stored externally. It does this by adding an ExternalSecret object to Kubernetes using a CustomResourceDefinition.

SAAP comes with fully managed External Secrets Operator to integrate with Vault and makes it extremely easy to consume secrets from Vault:

  1. Add tenant-vault-access template to the tenant:

    apiVersion: tenantoperator.stakater.com/v1alpha1
    kind: Tenant
    metadata:
      name: gabbar
    spec:
      users:
        owner:
        - user1
        - user2
      quota: medium
      namespacetemplate:
        templateInstances:
        - spec:
            template: tenant-vault-access
            sync: true
    
  2. Enable externalSecret in your deploy/values.yaml and provide details of the secret path in Vault:

    externalSecret:
      enabled: true
      secretStore:
        name: tenant-vault-secret-store
      files:   
      inventory-postgres: #Name of Kubernetes Secret
        data:
          postgresql-password: #Name of Kubernetes Secret Key
            remoteRef:
              key: inventory-postgres #Name of Vault Secret
              property: postgresql-password #Name of Vault Secret Key
    

When a secret is updated in Vault, the pod is automatically restarted by Reloader.

Option 2: Consume Vault secret via a Volume

To mount Vault secret in a volume do the following:

  1. Add label in serviceAccount so it can be granted Vault read access to secret path:

     serviceAccount:
       enabled: true
       additionalLabels: 
         stakater.com/vault-access: "true"
    
  2. Enable SecretProviderClass object in Helm values and define key and value path of Vault:

    secretProviderClass:
     enabled: true
     name: postgres-secret
     roleName: '{{.Release.Namespace}}'
     objects: 
       - objectName: postgresql-password
         secretPath: gabbar/data/postgres
         secretKey: postgresql-password
    
  3. Define volume in Helm values that use above created SecretProviderClass:

    deployment:
      volumes: 
        - name: postgres-secret
          csi:
            driver: secrets-store.csi.k8s.io
            readOnly: true
            volumeAttributes:
              secretProviderClass: postgres-secret
    
  4. Mount this volume in the container:

    volumeMounts:
    - name: postgres-secret
      readOnly: true
      mountPath: /data/db-creds
    

Option 3: Consume Vault secret via Environment Variable

To mount Vault secret in an environment variable:

  1. Enable SecretProviderClass object in Helm values and define key/value path and secret objects in Vault:

    secretProviderClass:
     enabled: true
     name: postgres-secret
     roleName: '{{.Release.Namespace}}'
     objects: 
       - objectName: postgresql-password
         secretPath: gabbar/data/postgres
         secretKey: postgresql-password
     secretObjects:
       - data:
         - key: postgres-password
           objectName: postgresql-password
         secretName: postgres-secret
         type: Opaque 
    

The value of secretName will be the name of the Kubernetes secret.

  1. Define volume in Helm values that use above created SecretProviderClass:

    deployment:
      volumes: 
        - name: postgres-secret
          csi:
            driver: secrets-store.csi.k8s.io
            readOnly: true
            volumeAttributes:
              secretProviderClass: postgres-secret
    
  2. Mount this volume in the container:

    volumeMounts:
    - name: postgres-secret
      readOnly: true
      mountPath: /data/db-creds
    

    Volume mount is required in order to create a Kubernetes secret.

  3. This secret can be used as an environment variable:

    env:
       - name: POSTGRES_PASSWORD
         valueFrom:
            secretKeyRef:
                name: postgres-secret
                key: postgres-password
    

Here is a working example.

Your secret should be available at the path defined above in Vault; a change in secret value in Vault will automatically restart the application by Stakater Reloader.

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