New to AppsCode Service Broker? Please start here.

Memcached Walk-through

This tutorial will show you how to use AppsCode Service Broker to provision and deprovision an Memcached cluster and bind to the Memcached service.

Before we start, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using Minikube. Then install Service Catalog onto your cluster. If you haven’t, please see the installation instructions for Service Catalog. Optionally you may install the Service Catalog CLI, svcat. Examples for both svcat and kubectl are provided so that you may follow this walk-through using svcat or using only kubectl.

If you’ve AppsCode Service Broker installed, then we are ready for the next step. If not, follow the instructions to install KubeDB and AppsCode Service Broker.

To keep things isolated, we are going to use a separate namespace called demo throughout this tutorial.

$ kubectl create ns demo
namespace/demo created

All commands in this document assume that you’re operating out of the root of this repository.

Check ClusterServiceClass and ClusterServicePlan for Memcached

First, list the available ClusterServiceClass resources:

$ kubectl get clusterserviceclasses
NAME                                   EXTERNAL-NAME   BROKER                    AGE
2010d83f-d908-4d9f-879c-ce8f5f527f2a   postgresql      appscode-service-broker   5m
315fc21c-829e-4aa1-8c16-f7921c33550d   elasticsearch   appscode-service-broker   5m
938a70c5-f2bc-4658-82dd-566bed7797e9   mysql           appscode-service-broker   5m
ccfd1c81-e59f-4875-a39f-75ba55320ce0   redis           appscode-service-broker   5m
d690058d-666c-45d8-ba98-fcb9fb47742e   mongodb         appscode-service-broker   5m
d88856cb-fe3f-4473-ba8b-641480da810f   memcached       appscode-service-broker   5m

$ svcat get classes
      NAME        NAMESPACE           DESCRIPTION
+---------------+-----------+------------------------------+
  postgresql                  KubeDB managed PostgreSQL
  elasticsearch               KubeDB managed ElasticSearch
  mysql                       KubeDB managed MySQL
  redis                       KubeDB managed Redis
  mongodb                     KubeDB managed MongoDB
  memcached                   KubeDB managed Memcached

Now, describe memcached class from the Service Broker.

$ svcat describe class memcached
  Name:              memcached
  Scope:             cluster
  Description:       KubeDB managed Memcached
  Kubernetes Name:   d88856cb-fe3f-4473-ba8b-641480da810f
  Status:            Active
  Tags:
  Broker:            appscode-service-broker

Plans:
       NAME                 DESCRIPTION
+----------------+--------------------------------+
  demo-memcached   Demo Memcached
  memcached        Memcached with custom
                   specification

To view the details of any plan in this class use command $ svcat describe plan <class_name>/<plan_name>. For example:

$ svcat describe plan memcached/memcached --scope cluster
  Name:              memcached
  Description:       Memcached with custom specification
  Kubernetes Name:   d40e49b2-f8fb-4d47-96d3-35089bd0942d
  Status:            Active
  Free:              true
  Class:             memcached

Instances:
No instances defined

Here we,ve used --scope flag to specify that our ClusterServiceBroker, ClusterServiceClass and ClusterServiceBroker resources are cluster scoped (not namespaced scope)

Provisioning: Creating a New ServiceInstance

AppsCode Service Broker currently supports two plans for memcached class as we can see above. Using demo-memcached plan we can provision a demo Memcached database. And using memcached plan we can provision a custom Memcached database with the full functionality of a Memcached CRD.

AppsCode Service Broker accepts only metadata and Memcached Spec as parameters for the plans of memcached class. The metadata and spec should be provided with key "metadata" and "spec" respectively. The metadata is optional for both of the plans available. But the spec is required for the custom plan and it must be valid.

Since a ClusterServiceClass named memcached exists in the cluster with a ClusterServicePlan named memcached, we can create a ServiceInstance pointing to them with custom specification as parameters.

Unlike ClusterServiceBroker, ClusterServiceClass and ClusterServicePlan resources, ServiceInstance resources must be namespaced. The latest version of .service catalog supports ServiceBroker, ServiceClass and ServicePlan resources that are namespace scoped and alternative to ClusterServiceBroker, ClusterServiceClass and ClusterServicePlan resources.

Create the ServiceInstance:

$ kubectl create -f docs/examples/memcached-instance.yaml
serviceinstance.servicecatalog.k8s.io/memcached created

After it is created, the service catalog controller will communicate with the service broker server to initiate provisioning. Now, see the details:

$ svcat describe instance memcached --namespace demo
  Name:        memcached
  Namespace:   demo
  Status:      Ready - The instance was provisioned successfully @ 2018-12-26 05:38:02 +0000 UTC
  Class:       memcached
  Plan:        memcached

Parameters:
  metadata:
    labels:
      app: my-memcached
  spec:
    podTemplate:
      spec:
        resources:
          limits:
            cpu: 500m
            memory: 128Mi
          requests:
            cpu: 250m
            memory: 64Mi
    replicas: 3
    terminationPolicy: WipeOut
    version: 1.5.4-v1

Bindings:
No bindings defined

The yaml configuration of this ServiceInstance:

kubectl get serviceinstance memcached --namespace demo -o yaml

Output:

apiVersion: servicecatalog.k8s.io/v1beta1
kind: ServiceInstance
metadata:
  creationTimestamp: "2018-12-26T05:38:01Z"
  finalizers:
  - kubernetes-incubator/service-catalog
  generation: 1
  labels:
    app: appscode-service-broker
  name: memcached
  namespace: demo
  resourceVersion: "101"
  selfLink: /apis/servicecatalog.k8s.io/v1beta1/namespaces/demo/serviceinstances/memcached
  uid: 6878eb72-08d0-11e9-9fa4-0242ac110006
spec:
  clusterServiceClassExternalName: memcached
  clusterServiceClassRef:
    name: d88856cb-fe3f-4473-ba8b-641480da810f
  clusterServicePlanExternalName: memcached
  clusterServicePlanRef:
    name: d40e49b2-f8fb-4d47-96d3-35089bd0942d
  externalID: 6878eb3d-08d0-11e9-9fa4-0242ac110006
  parameters:
    metadata:
      labels:
        app: my-memcached
    spec:
      podTemplate:
        spec:
          resources:
            limits:
              cpu: 500m
              memory: 128Mi
            requests:
              cpu: 250m
              memory: 64Mi
      replicas: 3
      terminationPolicy: WipeOut
      version: 1.5.4-v1
  updateRequests: 0
  userInfo:
    groups:
    - system:masters
    - system:authenticated
    uid: ""
    username: minikube-user
status:
  asyncOpInProgress: false
  conditions:
  - lastTransitionTime: "2018-12-26T05:38:02Z"
    message: The instance was provisioned successfully
    reason: ProvisionedSuccessfully
    status: "True"
    type: Ready
  deprovisionStatus: Required
  externalProperties:
    clusterServicePlanExternalID: d40e49b2-f8fb-4d47-96d3-35089bd0942d
    clusterServicePlanExternalName: memcached
    parameterChecksum: 9627fe20432ac96997f9ff1983cb3cb6e3b1a2d14184f2e44761a0eb13c31993
    parameters:
      metadata:
        labels:
          app: my-memcached
      spec:
        podTemplate:
          spec:
            resources:
              limits:
                cpu: 500m
                memory: 128Mi
              requests:
                cpu: 250m
                memory: 64Mi
        replicas: 3
        terminationPolicy: WipeOut
        version: 1.5.4-v1
    userInfo:
      groups:
      - system:masters
      - system:authenticated
      uid: ""
      username: minikube-user
  observedGeneration: 1
  orphanMitigationInProgress: false
  provisionStatus: Provisioned
  reconciledGeneration: 1

Binding: Creating a ServiceBinding for this ServiceInstance

We have a ready ServiceInstance. To use this service, we can bind to it. AppsCode Service Broker currently supports no parameter for binding. Now, create a ServiceBinding resource:

$ kubectl create -f docs/examples/memcached-binding.yaml
servicebinding.servicecatalog.k8s.io/memcached created

Once the ServiceBinding resource is created, the service catalog controller initiates binding process by communicating with the service broker server. In general, the broker server returns the necessary credentials in this step. Then the service catalog controller will insert them into a Kubernetes Secret object.

$ kubectl get servicebindings memcached --namespace demo
NAME        SERVICE-INSTANCE   SECRET-NAME   STATUS   AGE
memcached   memcached          memcached     Ready    1m

$ svcat get bindings memcached --namespace demo
    NAME      NAMESPACE   INSTANCE    STATUS
+-----------+-----------+-----------+--------+
  memcached   demo        memcached   Ready

$ svcat describe bindings memcached --namespace demo
  Name:        memcached
  Namespace:   demo
  Status:      Ready - Injected bind result @ 2018-12-26 07:58:54 +0000 UTC
  Secret:      memcached
  Instance:    memcached

Parameters:
  No parameters defined

Secret Data:
  Host       18 bytes
  Password   4 bytes
  Port       5 bytes
  Protocol   0 bytes
  RootCert   4 bytes
  URI        26 bytes
  Username   4 bytes

You can see the secret data by passing --show-secrets flag to the above command. The yaml configuration of this ServiceBinding resource is as follows:

kubectl get servicebindings memcached --namespace demo -o yaml

Output:

apiVersion: servicecatalog.k8s.io/v1beta1
kind: ServiceBinding
metadata:
  creationTimestamp: "2018-12-26T07:58:53Z"
  finalizers:
  - kubernetes-incubator/service-catalog
  generation: 1
  labels:
    app: appscode-service-broker
  name: memcached
  namespace: demo
  resourceVersion: "132"
  selfLink: /apis/servicecatalog.k8s.io/v1beta1/namespaces/demo/servicebindings/memcached
  uid: 16bb8d67-08e4-11e9-9fa4-0242ac110006
spec:
  externalID: 16bb8d1a-08e4-11e9-9fa4-0242ac110006
  instanceRef:
    name: memcached
  secretName: memcached
  userInfo:
    groups:
    - system:masters
    - system:authenticated
    uid: ""
    username: minikube-user
status:
  asyncOpInProgress: false
  conditions:
  - lastTransitionTime: "2018-12-26T07:58:54Z"
    message: Injected bind result
    reason: InjectedBindResult
    status: "True"
    type: Ready
  externalProperties:
    userInfo:
      groups:
      - system:masters
      - system:authenticated
      uid: ""
      username: minikube-user
  orphanMitigationInProgress: false
  reconciledGeneration: 1
  unbindStatus: Required

Here, the status has Ready condition which means the binding is now ready for use. This binding operation creates a Secret named memcached in namespace demo.

$ kubectl get secrets --namespace demo
NAME                  TYPE                                  DATA   AGE
default-token-2zx6l   kubernetes.io/service-account-token   3      153m
memcached             Opaque                                7      5m57s

Unbinding: Deleting the ServiceBinding

We can now delete the ServiceBinding resource we created in the Binding step (it is called Unbinding the ServiceInstance)

$ kubectl delete servicebinding memcached --namespace demo
servicebinding.servicecatalog.k8s.io "memcached" deleted

$ svcat unbind memcached --namespace demo
deleted memcached

After completion of unbinding, the Secret named memcached should be deleted.

$ kubectl get secrets --namespace demo
NAME                  TYPE                                  DATA   AGE
default-token-2zx6l   kubernetes.io/service-account-token   3      174m

Deprovisioning: Deleting the ServiceInstance

After unbinding the ServiceInstance, our next step is deleting the ServiceInstance resource we provisioned before. It is called Deprovisioning.

$ kubectl delete serviceinstance memcached --namespace demo
serviceinstance.servicecatalog.k8s.io "memcached" deleted

$ svcat deprovision memcached --namespace demo
deleted memcached

Cleanup

To cleanup the cluster, just uninstall the broker. It’ll delete the ClusterServiceBroker resource. Then service catalog controller automatically deletes all ClusterServiceClass and ClusterServicePlan resources that came from that broker.

$ kubectl get clusterserviceclasses
No resources found.

$ svcat get classes
  NAME   NAMESPACE   DESCRIPTION
+------+-----------+-------------+

Take your team where it needs to go.

Create your cluster in minutes. Our team is here to help and would be happy to chat with you.