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SecretEngine

What is a SecretEngine

A SecretEngine is a Kubernetes CustomResourceDefinition (CRD) which is designed to automate the process of enabling and configuring secret engines in Vault in a Kubernetes native way.

Secrets engines are components that store, generate, or encrypt data. Secrets engines are provided some set of data, they take some action on that data, and they return a result. Secrets engines are enabled at a “path” in Vault. In this way, each secrets engine defines its paths and properties. To the user, secrets engines behave similar to a virtual filesystem, supporting operations like read, write, and delete.

When a SecretEngine CRD is created, the KubeVault operator will perform the following operations:

• Creates vault policy for the secret engine. The vault policy name follows the naming format:k8s.{clusterName}.{metadata.namespace}.{metadata.name}. For example, the policy for GCP secret engine is below:

  path "<path>/config" {
        capabilities = ["create", "update", "read", "delete"]
  }
  
  path "<path>/roleset/*" {
      capabilities = ["create", "update", "read", "delete"]
  }
  
  path "<path>/token/*" {
      capabilities = ["create", "update", "read"]
  }
  
  path "<path>/key/*" {
      capabilities = ["create", "update", "read"]
  }
  

• Updates the Kubernetes auth role of the default k8s service account created with VaultServer with a new policy. The new policy will be merged with previous policies.

• Enables the secrets engine at a given path. By default, they are enabled at their “type” (e.g. “aws” is enabled at “aws/”).

• Configures the secret engine with the given configuration.

SecretEngine CRD Specification

Like any official Kubernetes resource, a SecretEngine object has TypeMeta, ObjectMeta, Spec and Status sections.

A sample SecretEngine object is shown below:

apiVersion: engine.kubevault.com/v1alpha1
kind: SecretEngine
metadata:
  name: first-secret-engine
  namespace: demo
spec:
  vaultRef:
    name: vault
  gcp:
    credentialSecret: "gcp-cred"
status:
  observedGeneration: 1
  phase: Success

Here, we are going to describe the various sections of the SecretEngine crd.

SecretEngine Spec

SecretEngine .spec contains information about the secret engine configuration and an AppBinding reference which is used to connect with a Vault server.

SecretEngine .spec has the following fields:

spec.vaultRef

spec.vaultRef is a required field that specifies an AppBinding reference which is used to connect with a Vault server. AppBinding must be on the same namespace of the secret engine crd.

spec:
  vaultRef:
    name: vault

spec.path

spec.path is an optional field that specifies the path where the secret engine will be enabled. The default path values are:

• GCP secret engine: gcp
• AWS secret engine: aws
• Azure secret engine: azure
• Database secret engine: database

spec:
  path: my-path

Secret engines are enabled at a “path” in Vault. When a request comes to Vault, the router automatically routes anything with the route prefix to the secrets engine. Since operator configures a secret engine to a specified path with SecretEngine resource, you can provide only one secret engine configuration out of the following ones:

• spec.aws : Specifies aws secret engine configuration

• spec.azure: Specifies azure secret engine configuration

• spec.gcp: Specifies gcp secret engine configuration

• spec.postgres: Specifies database(postgres) secret engine configuration

• spec.mongodb: Specifies database(mongodb) secret engine configuration

• spec.mysql: Specifies database(mysql) secret engine configuration

spec.aws

spec.aws specifies the configuration required to configure AWS secret engine. See more

spec:
  aws:
    credentialSecret: aws-cred
    region: us-east-1
    leaseConfig:
      lease: 1h
      leaseMax: 1h

• aws.credentialSecret : Required. Specifies the k8s secret name that contains AWS access key ID and secret access key

  spec:
    aws:
      credentialSecret: <secret-name>
  

  The data field of the secret must contain the following key-value pairs:

  data:
    access_kay: <access key>
    secret_key: <secret key>
  

• aws.region : Required. Specifies the AWS region.

• aws.iamEndpoint : Optional. Specifies a custom HTTP IAM endpoint to use.

• aws.stsEndpoint : Optional. Specifies a custom HTTP STS endpoint to use.

• config.maxRetries : Optional. Specifies the number of max retries the client should use for recoverable errors.

• aws.leaseConfig : Optional. Specifies the lease configuration.

  config:
    leaseConfig:
      lease: 1h
      leaseMax: 1h
  

  It has the following fields:

  • leaseConfig.lease : Optional. Specifies the lease value. Accepts time suffixed strings (eg, “1h”).

  • leaseConfig.leaseMax : Optional. Specifies the maximum lease value. Accepts time suffixed strings (eg, “1h”).

spec.azure

spec.azure specifies the configuration required to configure Azure secret engine. See more

spec:
  azure:
    credentialSecret: azure-cred
    environment: AzurePublicCloud

• credentialSecret : Required. Specifies the k8s secret name containing azure credentials. The data field of the mentioned k8s secret can have the following key-value pairs.

  • subscription-id : Required. Specifies the subscription id for the Azure Active Directory.

  • tenant-id : Required. Specifies the tenant id for the Azure Active Directory.

  • client-id : Optional. Specifies the OAuth2 client id to connect to Azure.

  • client-secret : Optional. Specifies the OAuth2 client secret to connect to Azure.

  data:
    subscription-id: <value>
    tenant-id: <value>
    client-id: <value>
    client-secret: <value>
  

• environment : Optional. Specifies the Azure environment. If not specified, Vault will use Azure Public Cloud.

spec.gcp

spec.gcp specifies the configuration required to configure GCP secret engine. See more

spec:
  gcp:
    credentialSecret: gcp-cred
    ttl: 0s
    maxTTL: 0s

• credentialSecret : Required. Specifies the k8s secret name that contains google application credentials.

  spec:
    gcp:
      credentialSecret: <secret-name>  
  

  The data field of the mentioned k8s secret must contain the following key-value pair:

  data:
    sa.json: <google-application-credential>
  

• ttl : Optional. Specifies default config TTL for long-lived credentials (i.e. service account keys). Default value is 0s.

• maxTTL : Optional. Specifies the maximum config TTL for long-lived credentials (i.e. service account keys). The default value is 0s.

spec.postgres

spec.postgres specifies the configuration required to configure PostgreSQL database secret engine. See more

 spec:
   postgres:
     databaseRef:
       name: <appbinding-name>
       namespace: <appbinding-namespace>
     pluginName: <plugin-name>
     allowedRoles:
       - "rule1"
       - "rule2"
     maxOpenConnections: <max-open-connection>
     maxIdleConnections: <max-idle-connection>
     maxConnectionLifetime: <max-connection-lifetime>

• databaseRef : Required. Specifies an AppBinding reference that is required to connect to a PostgreSQL database. It is also used to generate db_name (i.e. /v1/path/config/db_name) where the database secret engine will be configured at. The name of the db_name follows this pattern: k8s.{clusterName}.{namespace}.{name}.

  • name : Required. Specifies the AppBinding name.

  • namespace : Required. Specifies the AppBinding namespace.

  postgres:
    databaseRef:
      name: db-app
      namespace: demo
  

  The generated db_name for the above example will be: k8s.-.demo.db-app. If the cluster name is empty, it is replaced by “-”.

• pluginName : Optional. Specifies the name of the plugin to use for this connection. Default plugin name is postgres-database-plugin.

  postgres:
    pluginName: postgres-database-plugin
  

• allowedRoles : Optional. Specifies a list of roles allowed to use this connection. Default to "*" (i.e. any role can use this connection).

  postgres:
    allowedRoles:
      - "readonly"
  

• maxOpenConnections : Optional. Specifies the maximum number of open connections to the database. Default value 2.

  postgres:
    maxOpenConnections: 3
  

• maxIdleConnections : Optional. Specifies the maximum number of idle connections to the database. Zero uses the value of max_open_connections and a negative value disables idle connections. If larger than max_open_connections it will be reduced to be equal. Default value 0.

  postgres:
    maxIdleConnections: 1
  

• maxConnectionLifetime : Optional. Specifies the maximum amount of time a connection may be reused. If <= 0s connections are reused forever. Default value 0s.

  postgres:
    maxConnectionLifetime: 5s
  

spec.mongodb

spec.mongodb specifies the configuration required to configure MongoDB database secret engine. See more

  spec:
    mongodb:
      databaseRef:
        name: <appbinding-name>
        namespace: <namespace>
      pluginName: <plugin-name>
      allowedRoles:
        - "role1"
        - "role2"
      writeConcern: <write-concern>

• databaseRef : Required. Specifies an AppBinding reference that is required to connect to a MongoDB database. It is also used to generate db_name (i.e. /v1/path/config/db_name) where the database secret engine will be configured at. The naming of db_name follows: k8s.{clusterName}.{namespace}.{name}.

  • name : Required. Specifies the AppBinding name.

  • namespace : Required. Specifies the AppBinding namespace.

  mongodb:
    databaseRef:
      name: db-app
      namespace: demo
  

  The generated db_name for the above example will be: k8s.-.demo.db-app. If the cluster name is empty, it is replaced by “-”.

• pluginName : Optional. Specifies the name of the plugin to use for this connection. Default plugin name is mongodb-database-plugin.

  mongodb:
    pluginName: mongodb-database-plugin
  

• allowedRoles : Optional. Specifies a list of roles allowed to use this connection. Default to "*" (i.e. any role can use this connection).

  mongodb:
    allowedRoles:
      - "readonly"
  

• writeConcern : Optional. Specifies the MongoDB write concern. This is set for the entirety of the session, maintained for the life cycle of the plugin process. Must be a serialized JSON object, or a base64-encoded serialized JSON object. The JSON payload values map to the values in the Safe struct from the mongo driver.

  mongodb:
    writeConcern: `{ \"wmode\": \"majority\", \"wtimeout\": 5000 }`
  

spec.mysql

spec.mysql specifies the configuration required to configure MySQL database secret engine. See more

spec:
  mysql:
    databaseRef:
      name: <appbinding-name>
      namespace: <appbinding-namespace>
    pluginName: <plugin-name>
    allowedRoles:
      - "role1"
      - "role2"
      - ... ...
    maxOpenConnections: <max-open-connections>
    maxIdleConnections: <max-idle-connections>
    maxConnectionLifetime: <max-connection-lifetime>

• databaseRef : Required. Specifies an AppBinding reference that is required to connect to a MySQL database. It is also used to generate db_name (i.e. /v1/path/config/db_name) where the database secret engine will be configured at. The naming of db_name follows: k8s.{clusterName}.{namespace}.{name}.

  • name : Required. Specifies the AppBinding name.

  • namespace : Required. Specifies the AppBinding namespace.

  mysql:
    databaseRef:
      name: db-app
      namespace: demo
  

  The generated db_name for the above example will be: k8s.-.demo.db-app. If the cluster name is empty, it is replaced by “-”.

• pluginName : Optional. Specifies the name of the plugin to use for this connection. The default plugin name is mysql-database-plugin.

  mysql:
    pluginName: mysql-database-plugin
  

• allowedRoles : Optional. Specifies a list of roles allowed to use this connection. Default to "*" (i.e. any role can use this connection).

  mysql:
    allowedRoles:
      - "readonly"
  

• maxOpenConnections : Optional. Specifies the maximum number of open connections to the database. Default value 2.

  mysql:
    maxOpenConnections: 3
  

• maxIdleConnections : Optional. Specifies the maximum number of idle connections to the database. Zero uses the value of max_open_connections and a negative value disables idle connections. If larger than max_open_connections it will be reduced to be equal. Default value 0.

  mysql:
    maxIdleConnections: 1
  

• maxConnectionLifetime : Optional. Specifies the maximum amount of time a connection may be reused. If <= 0s connections are reused forever. Default value 0s.

  mysql:
    maxConnectionLifetime: 5s
  

SecretEngine Status

status shows the status of the SecretEngine. It is managed by the KubeVault operator. It contains the following fields:

• observedGeneration: Specifies the most recent generation observed for this resource. It corresponds to the resource’s generation, which is updated on mutation by the API Server.

• phase: Indicates whether the secret engine successfully configured in the Vault or not.

• conditions : Represent observations of a SecretEngine.