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RabbitMQ

KubeDB managed RabbitMQ

RabbitMQ is a Kubernetes Custom Resource Definitions (CRD). It provides declarative configuration for RabbitMQ in a Kubernetes native way. You only need to describe the desired database configuration in a RabbitMQ object, and the KubeDB operator will create Kubernetes objects in the desired state for you.

RabbitMQ Spec

As with all other Kubernetes objects, a RabbitMQ needs apiVersion, kind, and metadata fields. It also needs a .spec section. Below is an example RabbitMQ object.

apiVersion: kubedb.com/v1alpha2
kind: RabbitMQ
metadata:
  name: rabbitmq
  namespace: rabbit
spec:
  version: "3.13.2"
  authSecret:
    name: rabbit-auth
  configSecret:
    name: rabbit-custom-config
  enableSSL: true
  replicas: 4
  storage:
    accessModes:
      - ReadWriteOnce
    resources:
      requests:
        storage: 1Gi
    storageClassName: "standard"
  serviceTemplates:
  - alias: primary
    spec:
      type: LoadBalancer
  - alias: stats
    spec:
      type: LoadBalancer
  podTemplate:
    spec:
      containers:
        - name: "rabbitmq"
          resources:
            requests:
              cpu: "500m"
            limits:
              cpu: "600m"
              memory: "1.5Gi"
  tls:
    issuerRef:
      apiGroup: "cert-manager.io"
      kind: Issuer
      name: rabbit-ca-issuer
    certificates:
      - alias: client
        subject:
          organizations:
            - kubedb
        emailAddresses:
          - [email protected]
      - alias: server
        subject:
          organizations:
            - kubedb
        emailAddresses:
          - [email protected]
  monitor:
    agent: prometheus.io/operator
    prometheus:
      serviceMonitor:
        labels:
          release: prometheus
        interval: 10s
  healthChecker:
    periodSeconds: 15
    timeoutSeconds: 10
    failureThreshold: 2
    disableWriteCheck: false
  storageType: Durable
  deletionPolicy: Halt  

spec.autoOps

AutoOps is an optional field to control the generation of versionUpdate & TLS-related recommendations.

spec.version

spec.version is a required field specifying the name of the RabbitMQVersion crd where the docker images are specified. Currently, when you install KubeDB, it creates the following RabbitMQVersion resources,

• 3.12.12, 3.13.2

spec.replicas

spec.replicas the number of nodes in RabbitMQ cluster.

KubeDB uses PodDisruptionBudget to ensure that majority of these replicas are available during voluntary disruptions so that quorum is maintained.

spec.authSecret

spec.authSecret is an optional field that points to a Secret used to hold credentials for RabbitMQ superuser. If not set, KubeDB operator creates a new Secret {RabbitMQ-object-name}-auth for storing the password for RabbitMQ superuser for each RabbitMQ object.

We can use this field in 3 mode.

1. Using an external secret. In this case, You need to create an auth secret first with required fields, then specify the secret name when creating the RabbitMQ object using spec.authSecret.name & set spec.authSecret.externallyManaged to true.

authSecret:
  name: <your-created-auth-secret-name>
  externallyManaged: true

2. Specifying the secret name only. In this case, You need to specify the secret name when creating the RabbitMQ object using spec.authSecret.name. externallyManaged is by default false.

authSecret:
  name: <intended-auth-secret-name>

3. Let KubeDB do everything for you. In this case, no work for you.

AuthSecret contains a user key and a password key which contains the username and password respectively for RabbitMQ superuser.

Example:

$ kubectl create secret generic -n demo rabbit-auth \
  --from-literal=username=rabbit-admin \
  --from-literal=password=mypassword
secret/rabbit-auth created

apiVersion: v1
data:
  password: bXlwYXNzd29yZA==
  username: cmFiYml0LWFkbWlu
kind: Secret
metadata:
  creationTimestamp: "2024-09-09T03:56:36Z"
  name: rabbit-auth
  namespace: demo
  resourceVersion: "263545"
  uid: 4734f693-9ff8-4f42-bcac-ab9b5ba17afd
type: Opaque

Secrets provided by users are not managed by KubeDB, and therefore, won’t be modified or garbage collected by the KubeDB operator (version 0.13.0 and higher).

spec.tls

spec.tls specifies the TLS/SSL configurations for the RabbitMQ. KubeDB uses cert-manager v1 api to provision and manage TLS certificates.

The following fields are configurable in the spec.tls section:

• issuerRef is a reference to the Issuer or ClusterIssuer CR of cert-manager that will be used by KubeDB to generate necessary certificates.

  • apiGroup is the group name of the resource that is being referenced. Currently, the only supported value is cert-manager.io.
  • kind is the type of resource that is being referenced. KubeDB supports both Issuer and ClusterIssuer as values for this field.
  • name is the name of the resource (Issuer or ClusterIssuer) being referenced.

• certificates (optional) are a list of certificates used to configure the server and/or client certificate. It has the following fields:

  • alias represents the identifier of the certificate. It has the following possible value:

    • server is used for server certificate identification.
    • client is used for client certificate identification.
    • metrics-exporter is used for metrics exporter certificate identification.

  • secretName (optional) specifies the k8s secret name that holds the certificates.

    This field is optional. If the user does not specify this field, the default secret name will be created in the following format: <database-name>-<cert-alias>-cert.

  • subject (optional) specifies an X.509 distinguished name. It has the following possible field,

    • organizations (optional) are the list of different organization names to be used on the Certificate.
    • organizationalUnits (optional) are the list of different organization unit name to be used on the Certificate.
    • countries (optional) are the list of country names to be used on the Certificate.
    • localities (optional) are the list of locality names to be used on the Certificate.
    • provinces (optional) are the list of province names to be used on the Certificate.
    • streetAddresses (optional) are the list of a street address to be used on the Certificate.
    • postalCodes (optional) are the list of postal code to be used on the Certificate.
    • serialNumber (optional) is a serial number to be used on the Certificate. You can find more details from Here

  • duration (optional) is the period during which the certificate is valid.

  • renewBefore (optional) is a specifiable time before expiration duration.

  • dnsNames (optional) is a list of subject alt names to be used in the Certificate.

  • ipAddresses (optional) is a list of IP addresses to be used in the Certificate.

  • uris (optional) is a list of URI Subject Alternative Names to be set in the Certificate.

  • emailAddresses (optional) is a list of email Subject Alternative Names to be set in the Certificate.

  • privateKey (optional) specifies options to control private keys used for the Certificate.

    • encoding (optional) is the private key cryptography standards (PKCS) encoding for this certificate’s private key to be encoded in. If provided, allowed values are “pkcs1” and “pkcs8” standing for PKCS#1 and PKCS#8, respectively. It defaults to PKCS#1 if not specified.

spec.storageType

spec.storageType is an optional field that specifies the type of storage to use for database. It can be either Durable or Ephemeral. The default value of this field is Durable. If Ephemeral is used then KubeDB will create RabbitMQ database using emptyDir volume. In this case, you don’t have to specify spec.storage field. Specify spec.ephemeralStorage spec instead.

spec.storage

Since 0.9.0-rc.0, If you set spec.storageType: to Durable, then spec.storage is a required field that specifies the StorageClass of PVCs dynamically allocated to store data for the database. This storage spec will be passed to the StatefulSet created by KubeDB operator to run database pods. You can specify any StorageClass available in your cluster with appropriate resource requests.

• spec.storage.storageClassName is the name of the StorageClass used to provision PVCs. PVCs don’t necessarily have to request a class. A PVC with its storageClassName set equal to "" is always interpreted to be requesting a PV with no class, so it can only be bound to PVs with no class (no annotation or one set equal to “”). A PVC with no storageClassName is not quite the same and is treated differently by the cluster depending on whether the DefaultStorageClass admission plugin is turned on.
• spec.storage.accessModes uses the same conventions as Kubernetes PVCs when requesting storage with specific access modes.
• spec.storage.resources can be used to request specific quantities of storage. This follows the same resource model used by PVCs.

To learn how to configure spec.storage, please visit the links below:

• https://kubernetes.io/docs/concepts/storage/persistent-volumes/#persistentvolumeclaims

spec.monitor

RabbitMQ managed by KubeDB can be monitored with builtin-Prometheus and Prometheus operator out-of-the-box. To learn more,

• Monitor RabbitMQ with builtin Prometheus
• Monitor RabbitMQ with Prometheus operator

spec.configSecret

spec.configSecret is an optional field that allows users to provide custom configuration for RabbitMQ. You can provide the custom configuration in a secret, then you can specify the secret name spec.configSecret.name.

Please note that, the secret key needs to be rabbitmq.conf.

To learn more about how to use a custom configuration file see here.

spec.podTemplate

KubeDB allows providing a template for pod through spec.podTemplate. KubeDB operator will pass the information provided in spec.podTemplate to the PetSet created for RabbitMQ.

KubeDB accept following fields to set in spec.podTemplate:

• metadata:
  • annotations (pod’s annotation)
  • labels (pod’s labels)
• controller:
  • annotations (PetSet’s annotation)
  • labels (PetSet’s labels)
• spec:
  • volumes
  • initContainers
  • containers
  • imagePullSecrets
  • nodeSelector
  • affinity
  • serviceAccountName
  • schedulerName
  • tolerations
  • priorityClassName
  • priority
  • securityContext
  • livenessProbe
  • readinessProbe
  • lifecycle

You can check out the full list here. Uses of some field of spec.podTemplate is described below,

spec.podTemplate.spec.nodeSelector

spec.podTemplate.spec.nodeSelector is an optional field that specifies a map of key-value pairs. For the pod to be eligible to run on a node, the node must have each of the indicated key-value pairs as labels (it can have additional labels as well). To learn more, see here .

spec.podTemplate.spec.resources

spec.podTemplate.spec.resources is an optional field. This can be used to request compute resources required by the database pods. To learn more, visit here.

spec.serviceTemplates

You can also provide template for the services created by KubeDB operator for Kafka cluster through spec.serviceTemplates. This will allow you to set the type and other properties of the services.

KubeDB allows following fields to set in spec.serviceTemplates:

• alias represents the identifier of the service. It has the following possible value:
  • stats is used for the exporter service identification.
• metadata:
  • labels
  • annotations
• spec:
  • type
  • ports
  • clusterIP
  • externalIPs
  • loadBalancerIP
  • loadBalancerSourceRanges
  • externalTrafficPolicy
  • healthCheckNodePort
  • sessionAffinityConfig

See here to understand these fields in detail.

spec.deletionPolicy

deletionPolicy gives flexibility whether to nullify(reject) the delete operation of RabbitMQ CR or which resources KubeDB should keep or delete when you delete RabbitMQ CR. KubeDB provides following four deletion policies:

• DoNotTerminate
• Delete (Default)
• WipeOut

When deletionPolicy is DoNotTerminate, KubeDB takes advantage of ValidationWebhook feature in Kubernetes 1.9.0 or later clusters to implement DoNotTerminate feature. If admission webhook is enabled, DoNotTerminate prevents users from deleting the database as long as the spec.deletionPolicy is set to DoNotTerminate.

Following table show what KubeDB does when you delete Pgpool CR for different deletion policies,

If you don’t specify spec.deletionPolicy KubeDB uses Delete deletion policy by default.

spec.healthChecker

It defines the attributes for the health checker.

• spec.healthChecker.periodSeconds specifies how often to perform the health check.
• spec.healthChecker.timeoutSeconds specifies the number of seconds after which the probe times out.
• spec.healthChecker.failureThreshold specifies minimum consecutive failures for the healthChecker to be considered failed.
• spec.healthChecker.disableWriteCheck specifies whether to disable the writeCheck or not.

Know details about KubeDB Health checking from this blog post.

Next Steps

• Learn how to use KubeDB to run a RabbitMQ database here.
• Want to hack on KubeDB? Check our contribution guidelines.