Chapter 2. Deploying AMQ Broker on OpenShift Container Platform using an Operator

2.1. Overview of the AMQ Broker Operator

Kubernetes - and, by extension, OpenShift Container Platform - includes features such as secret handling, load balancing, service discovery, and autoscaling that enable you to build complex distributed systems. Operators are programs that enable you to package, deploy, and manage Kubernetes applications. Often, Operators automate common or complex tasks.

Commonly, Operators are intended to provide:

  • Consistent, repeatable installations
  • Health checks of system components
  • Over-the-air (OTA) updates
  • Managed upgrades

Operators use Kubernetes extension mechanisms called Custom Resource Definitions and corresponding Custom Resources to ensure that your custom objects look and act just like native, built-in Kubernetes objects. Custom Resource Definitions and Custom Resources are how you specify the configuration of the OpenShift objects that you plan to deploy.

Previously, you could use only application templates to deploy AMQ Broker on OpenShift Container Platform. While templates are effective for creating an initial deployment, they do not provide a mechanism for updating the deployment. Operators enable you to make changes while your broker instances are running, because they are always listening for changes to your Custom Resources, where you specify your configuration. When you make changes to a Custom Resource, the Operator reconciles the changes with the existing broker installation in your project, and makes it reflect the changes you have made.

2.2. Overview of Custom Resource Definitions

In general, a Custom Resource Definition (CRD) is a schema of configuration items that you can modify for a custom OpenShift object deployed with an Operator. An accompanying Custom Resource (CR) file enables you to specify values for configuration items in the CRD. If you are an Operator developer, what you expose through a CRD essentially becomes the API for how a deployed object is configured and used. You can directly access the CRD through regular HTTP curl commands, because the CRD gets exposed automatically through Kubernetes. The Operator also interacts with Kubernetes via the kubectl command using HTTP requests.

The main broker CRD is the broker_v2alpha1_activemqartemis file in the deploy/crds directory of the archive that you download and extract when installing the Operator. This CRD enables you to configure a broker deployment in a given OpenShift project. The other CRDs in the deploy/crds directory are for configuring addresses and for the Operator to use when instantiating a scaledown controller .

When deployed, each CRD is a separate controller, running independently within the Operator.

For a complete configuration reference for each CRD see:

2.2.1. Sample broker Custom Resources

The AMQ Broker Operator archive that you download and extract during installation includes sample CR files in the deploy/crs directory. These sample CR files enable you to:

  • Deploy a minimal broker without SSL or clustering.
  • Define addresses.

The broker Operator archive that you download and extract also includes CRs for example deployments in the deploy/examples directory, as listed below.

basic-deployment.yaml
Basic broker deployment.
persistence-deployment.yaml
Broker deployment with persistent storage.
cluster-deployment.yaml
Deployment of clustered brokers.
persistence-cluster-deployment.yaml
Deployment of clustered brokers with persistent storage.
ssl-deployment.yaml
Broker deployment with SSL security.
ssl-persistence-deployment.yaml
Broker deployment with SSL security and persistent storage.
address-queue-create.yaml
Address and queue creation.
aio-journal.yaml
Use of asynchronous I/O (AIO) with the broker journal.

The procedures in the following sections show you how to use an Operator, CRD, and some CRs to create some container-based broker deployments on OpenShift Container Platform. When you have successfully completed the procedures, you will have the Operator running in an individual Pod. Each broker instance that you create will run in a separate StatefulSet containing a Pod in the project. You will use a dedicated CR to define addresses in your broker deployments.

Note

You cannot create more than one broker deployment in a given OpenShift project by deploying multiple broker CR instances. However, when you have created a broker deployment in a project, you can deploy multiple CR instances for addresses.

2.3. Installing the AMQ Broker Operator

The procedures in this section show you how to install and deploy the AMQ Broker Operator on OpenShift Container Platform. In subsequent procedures, you use this Operator to deploy some broker instances.

Note

Deploying the Custom Resource Definitions (CRDs) that accompany the AMQ Broker Operator requires administrator privileges for your OpenShift cluster. When the Operator is deployed, a regular user can deploy broker instances via the provided Custom Resources (CRs).

2.3.1. Getting the Operator code

This procedure shows you how to access and prepare the code you need to install the AMQ Broker Operator.

Procedure

  1. In your web browser, navigate to the AMQ Broker 7.5.0 Software Downloads page.
  2. Click Download next to the Operator archive file that you want to install. Choose an archive file based on the information in the following table.

    PlatformDownload titleCompressed archive file name

    OpenShift Container Platform

    AMQ Broker 7.5 Operator Installation Files

    amq-broker-operator-7.5.0-ocp-install-examples.zip

    OpenShift Container Platform on IBM Z

    AMQ Broker 7.5 Operator Installation Files for IBM zSeries

    amq-broker-operator-7.5.0-Z-ocp-install-examples.zip

  3. When the download is complete, move the archive to your chosen installation directory.

    This example moves the OpenShift Container Platform Operator archive to a directory called ~/broker/operator.

    mkdir ~/broker/operator
    mv amq-broker-operator-7.5.0-ocp-install-examples.zip ~/broker/operator
  4. In your chosen installation directory, extract the contents of the archive. For example:

    cd ~/broker/operator
    unzip amq-broker-operator-7.5.0-ocp-install-examples.zip
  5. Log in to OpenShift Container Platform as a cluster administrator.

    $ oc login -u system:admin
  6. Create or log in to the project in which you want to install the Operator.

    $ oc new-project <project_name>

    or

    $ oc project <project_name>
  7. Specify a service account to use with the Operator.

    1. In the deploy directory of the Operator archive that you extracted, open the service_account.yaml file.
    2. Set the kind element to ServiceAccount.
    3. In the metadata section, assign a name to the service account. The default name is amq-broker-operator.
  8. Specify a role name for the Operator.

    1. Open the role.yaml file. This file specifies the resources that the Operator can use and modify.
    2. Set the kind element to Role.
    3. In the metadata section, assign a name to the role. The default name is amq-broker-operator.
  9. Specify a role binding for the Operator. The role binding binds the previously-created service account to the Operator role, based on the names you specified.

    Open the role_binding.yaml file. Add lines that look like the following:

    metadata:
        name: amq-broker-operator
    subjects:
        kind: ServiceAccount
        name: amq-broker-operator
    roleRef:
        kind: Role
        name: amq-broker-operator

2.3.2. Deploying the Operator

The procedure in this section shows you how to deploy the AMQ Broker Operator in your OpenShift project.

Prerequisites

  • Starting in AMQ Broker 7.3, you use a new version of the Red Hat Container Registry to access container images. This new version of the registry requires you to become an authenticated user before you can access images. Before you can follow the procedure in this section, you must first complete the steps described in Red Hat Container Registry Authentication.
  • If you intend to deploy brokers with persistent storage and do not have container-native storage in your OpenShift cluster, you need to manually provision persistent volumes and ensure that they are available to be claimed by the Operator. For example, if you want to create a cluster of two brokers with persistent storage (that is, by setting persistenceEnabled=true in your Custom Resource), you need to have two persistent volumes available. By default, each broker instance requires storage of 2 GiB.

    If you specify persistenceEnabled=false in your Custom Resource, the deployed brokers uses ephemeral storage. Ephemeral storage means that that every time you restart the broker Pods, any existing data is lost.

    For more information about provisioning persistent storage in OpenShift Container Platform, see Understanding persistent storage in the OpenShift Container Platform documentation.

Procedure

  1. In the OpenShift Container Platform web console, open the project you created, or the existing project in which you want your broker deployment.

    If you created a new project, it is currently empty. You see that there are no deployments, StatefulSets, Pods, Services, or Routes.

  2. Prepare the project to receive the operator.

    1. Create the service account.

      $ oc create -f deploy/service_account.yaml
    2. Create the role.

      $ oc create -f deploy/role.yaml
    3. Create the role binding.

      $ oc create -f deploy/role_binding.yaml
    4. Deploy the broker CRD to the OpenShift cluster.

      $ oc create -f deploy/crds/broker_v2alpha1_activemqartemis_crd.yaml
      Note

      You must install the CRDs before deploying and starting the Operator. If not, the Operator logs will show messages instructing you to do so.

    5. Deploy the addressing CRD.

      $ oc create -f deploy/crds/broker_v2alpha1_activemqartemisaddress_crd.yaml
    6. Deploy the scaledown CRD.

      $ oc create -f deploy/crds/broker_v2alpha1_activemqartemisscaledown_crd.yaml
  3. Link the pull secret associated with the account used for authentication in the Red Hat Container Registry with the default, deployer, and builder service accounts for your OpenShift project.

    $ oc secrets link --for=pull default <secret-name>
    $ oc secrets link --for=pull deployer <secret-name>
    $ oc secrets link --for=pull builder <secret-name>
    Note

    In OpenShift Container Platform 4.1, you can also use the web console to associate a pull secret with a project in which you want to deploy container images such as the AMQ Broker Operator. To do this, click AdministrationService Accounts. Specify the pull secret associated with the account that you use for authentication in the Red Hat Container Registry.

  4. In the deploy directory of the Operator archive that you downloaded and extracted, open the operator.yaml file. Update spec.containers.image with the full path to the latest Operator image for AMQ Broker 7.5 in the Red Hat Container Registry.

    Specify the Operator image name for your platform, based on the information in the following table.

    PlatformRepository nameLatest version tag

    OpenShift Container Platform

    amq7/amq-broker-rhel7-operator

    0.9

    OpenShift Container Platform on IBM Z

    amq7/amq-broker-rhel8-operator

    0.10

    For example, to deploy the Operator for OpenShift Container Platform, specify the latest version tag for the Operator container image in the amq7/amq-broker-rhel7-operator repository, as shown below.

    spec:
        template:
            spec:
                containers:
                    image: registry.redhat.io/amq7/amq-broker-rhel7-operator:0.9
  5. Deploy the Operator.

    $ oc create -f deploy/operator.yaml

    In your OpenShift project, the amq-broker-operator image that you deployed starts in a new Pod.

    The information on the Events tab of the new Pod confirms that OpenShift has deployed the Operator image you specified, assigned a new container to a node in your OpenShift cluster, and started the new container.

    In addition, if you click the Logs tab within the Pod, the output includes line like the following:

    ...
    {"level":"info","ts":1553619035.8302743,"logger":"kubebuilder.controller","msg":"Starting Controller","controller":"activemqartemisaddress-controller"}
    {"level":"info","ts":1553619035.830541,"logger":"kubebuilder.controller","msg":"Starting Controller","controller":"activemqartemis-controller"}
    {"level":"info","ts":1553619035.9306898,"logger":"kubebuilder.controller","msg":"Starting workers","controller":"activemqartemisaddress-controller","worker count":1}
    {"level":"info","ts":1553619035.9311671,"logger":"kubebuilder.controller","msg":"Starting workers","controller":"activemqartemis-controller","worker count":1}

    The preceding output confirms that the newly-deployed Operator is communicating with Kubernetes, that the controllers for the broker and addressing are running, and that these controllers have started some workers.

2.4. Deploying a basic broker

The following procedures show you how to deploy a basic broker instance in your OpenShift project when you have installed the AMQ Broker Operator.

Note

You cannot create more than one broker deployment in a given OpenShift project by deploying multiple broker CR instances. However, when you have created a broker deployment in a project, you can deploy multiple CR instances for addresses.

Prerequisites

  • Starting in AMQ Broker 7.3, you use a new version of the Red Hat Container Registry to access container images. This new version of the registry requires you to become an authenticated user before you can access images. Before you can follow the procedure in this section, you must first complete the steps described in Red Hat Container Registry Authentication.
  • The Broker Operator is already installed. See Installing the Broker Operator.

Procedure

When you have successfully installed the Operator, the Operator is running and listening for changes related to your Custom Resources (CRs). This example procedure shows you how to use a CR to deploy a basic broker in your project.

  1. In the deploy/crs directory of the Operator archive that you downloaded and extracted, open the broker_v2alpha1_activemqartemis_cr.yaml file. This file is an instance of a basic broker Custom Resource.

    For the broker Operator for OpenShift Container Platform, the default contents of the file look as follows:

    apiVersion: broker.amq.io/v2alpha1
    kind: ActiveMQArtemis
    metadata:
      name: ex-aao
      application: ex-aao-app
      namespace: aao-demo-0
      labels:
        ActiveMQArtemis: ex-aao
        application: ex-aao-app
    ...
    spec:
        deploymentPlan:
            size: 2
            image: registry.redhat.io/amq7/amq-broker:7.5
    size
    Specifies the number of brokers to deploy. For a clustered deployment, this value is 2 or greater. However, for a basic broker instance, change the value to 1.
    image

    Specifies the container image to use to launch the broker. Default values for the image attribute are shown in the following table.

    PlatformImage

    OpenShift Container Platform

    registry.redhat.io/amq7/amq-broker:7.5

    OpenShift Container Platform on IBM Z

    registry.redhat.io/amq7/amq-broker-openj9-11-rhel8:7.5

  2. Deploy a basic broker, based on the broker_v2alpha1_activemqartemis CR.

    $ oc create -f deploy/crs/broker_v2alpha1_activemqartemis_cr.yaml

    In the OpenShift Container Platform web console, click WorkloadsStateful Sets (OpenShift Container Platform 4.1) or ApplicationsStateful Sets (OpenShift Container Platform 3.11). You see a new Stateful Set called ex-aao-ss.

    Expand the ex-aao-ss Stateful Set section. You see that there is one Pod, corresponding to the single broker that you defined in the Custom Resource.

    On the Events tab of the running Pod, you see that the broker has started.

Note

To delete a broker deployment, delete the Custom Resource instance that you created for the deployment. It is not sufficient to delete only the Stateful Set.

Additional resources

2.5. Applying Custom Resource changes to running broker deployments

The following are some things to note about applying Custom Resource (CR) changes to running broker deployments:

  • You cannot dynamically update the persistenceEnabled attribute in your CR. To change this attribute, scale your cluster down to zero brokers. Delete the existing CR. Then, recreate and redeploy the CR with your changes, also specifying a deployment size.
  • If the image attribute in your CR uses a floating tag such as 7.5, then your deployment automatically pulls new image versions as they become available in the Red Hat Container Registry, provided that the imagePullPolicy attribute in your deployment configuration or Stateful Set is set to Always. For example, if your deployment currently uses a broker image version, 7.5-2, and a newer broker image version, 7.5-3, becomes available, then your deployment automatically pulls and uses the new image version. To use the new image, each broker in the deployment scales down and then back up. If you have multiple brokers in your deployment, each broker scales down and back up, in sequence.
  • The value of the deploymentPlan.size attribute in your CR overrides any change you make to size of your broker deployment via the oc scale command. For example, suppose you use oc scale to change the size of a deployment from three brokers to two, but the value of deploymentPlan.size in your CR is still 3. In this case, OpenShift initially scales the deployment down to two brokers. However, when the scaledown operation is complete, the Operator restores the deployment to three brokers, as specified in the CR.
  • During an active scaling event, any further changes that you apply are queued by the Operator and executed only when scaling is complete. For example, suppose you scale the size of your deployment down from four brokers to one. Then, while scaledown is taking place, you also change the values of the broker administrator user name and password. In this case, the Operator queues the user name and password changes until the deployment is running with one active broker.
  • All Custom Resource changes – apart from changing the size of your deployment, or changing the value of the expose attribute for acceptors, connectors, or the console – cause existing brokers to scale down and then back up. If you have multiple brokers in your deployment, only one broker scales down at a time.

2.6. Configuring Operator-based broker deployments for client connections

2.6.1. Configuring brokers to accept client connections

2.6.1.1. Configuring acceptors

To enable client connections to a broker in your OpenShift deployment, you define acceptors on the broker Pod. Acceptors define how the broker accepts connections.

You define acceptors in the Custom Resource (CR) used for your broker deployment. A single acceptor can accept multiple client connections, up to a maximum limit specified by the connectionsAllowed parameter of your acceptor configuration . You can define acceptors for both internal clients (that is, client applications in the same OpenShift cluster as the broker) and external clients (applications outside OpenShift). For each acceptor that you define, a dedicated Service and Route is created in the broker Pod.

When you create an acceptor, you specify information such as the messaging protocols to enable on the acceptor, and the port on the broker Pod to be exposed to use these protocols.

If you do not define any acceptors in your CR, then your broker Pods use a minimum configuration of a single acceptor, created by default, on port 61616. This default acceptor has only the Core protocol specified. The reason that all broker use this minimum acceptor configuration is that clustering requires the configuration, and clustering is enabled by default.

In addition, port 8161 is automatically exposed on the broker Pod for use by the AMQ Broker management console. Within the OpenShift network, this console port can be accessed via the headless service that runs in your broker deployment.

You can also specify whether to enable SSL on the acceptor, using the sslEnabled parameter. If the acceptor uses SSL, you can specify information such as:

  • The secret name used to store SSL credentials (required).
  • The cipher suites and and protocols to use for SSL communication.
  • Whether the acceptor uses two-way SSL, that is, mutual authentication between the broker and the client.
Note

If the acceptor that you define uses SSL, then the SSL credentials used by the acceptor must be stored in a secret. You must create your own secret and specify this secret name in the sslSecret parameter of your acceptor configuration. If you do not specify a custom secret name in the sslSecret parameter, the acceptor assumes a default secret name. The default secret name uses the format <Custom Resource name>-<acceptor-name>-secret. For example, ex-aao-amqp-secret. The SSL credentials required in the secret are broker.ks, which must be a base64-encoded keystore, client.ts, which must be a base64-encoded truststore, and keyStorePassword and trustStorePassword, which are passwords specified in raw text. This requirement is the same for any connectors that you configure. For information about generating credentials for SSL connections, see Generating credentials for SSL connections.

To connect to the broker from outside OpenShift via a NodePort, use a URI formatted like protocol://any.ocp.node.ip:ProtocolPortNumber. If you have configured a Route, you need to specify the Route name. The Route name must resolve to the node that’s hosting the OpenShift router. The OpenShift router uses the specified hostname to determine where to send the traffic inside the OpenShift internal network.

Important

To configure acceptors, your Operator-based broker deployment must specify a broker container image for AMQ Broker 7.5 or later. For an example of specifying a broker container image in your deployment, see Deploying a basic broker.

Note

The preceding information applies only to broker deployments based on the AMQ Broker Operator. If you have used application templates to create your broker deployment instead, you cannot create individual acceptors to directly connect external clients to the protocol-specific ports that OpenShift exposes on the broker Pod. For more information, see Connecting external clients to templates-based broker deployments.

Additional resources

2.6.1.2. Generating credentials for SSL connections

For SSL connections, AMQ Broker requires a broker keystore, a client keystore, and a client truststore that includes the broker keystore. This procedure shows you how to generate the credentials. The procedure uses Java Keytool, a package included with the Java Development Kit.

Procedure

  1. Generate a self-signed certificate for the broker keystore.

    $ keytool -genkey -alias broker -keyalg RSA -keystore broker.ks
  2. Export the certificate, so that it can be shared with clients.

    $ keytool -export -alias broker -keystore broker.ks -file broker_cert
  3. Generate a self-signed certificate for the client keystore.

    $ keytool -genkey -alias client -keyalg RSA -keystore client.ks
  4. Create a client truststore that imports the broker certificate.

    $ keytool -import -alias broker -keystore client.ts -file broker_cert
  5. Use the broker keystore file to create a secret to store the SSL credentials, as shown in the example below.

    $ oc secrets new ex-aao-amqp-secret broker.ks client.ts
  6. Add the secret to the service account that you created when installing the Operator, as shown in the example below.

    $ oc secrets add sa/amq-broker-operator secret/ex-aao-amqp-secret

2.6.1.3. Networking services in your broker deployments

On the Networking pane of the OpenShift Container Platform web console for your broker deployment, there are two running services; a headless service and a ping service. The default name of the headless service uses the format <Custom Resource name>-hdls-svc, for example, ex-aao-hdls-svc. The default name of the ping service uses a format of <Custom Resource name>-ping-svc, for example, ex-aao-ping-svc.

The headless service provides access to ports 8161 and 61616 on each broker Pod. Port 8161 is used by the broker management console, and port 61616 is used for broker clustering.

The ping service is a service used by the brokers for discovery, and enables brokers to form a cluster within the OpenShift environment. Internally, this service exposes the 8888 port.

2.6.2. Connecting a broker to the AMQ Broker management console

The broker hosts its own management console at port 8161. Each broker Pod in your deployment has a Service and Route that provide access to the console.

The following procedure shows how to connect to the AMQ Broker management console for a running broker instance.

Prerequisites

2.6.2.1. Accessing the broker management console

Each broker Pod in your deployment has a service that provides access to the console. The default name of this service uses the format <Custom Resource name>-wconsj-<broker Pod ordinal>-svc. For example, for broker Pod 0 of your deployment, the service name is ex-aao-wconsj-0-svc. Each Service has a corresponding Route that uses the format `<Custom Resource name>-wconsj-<broker Pod ordinal>-svc-rte. For example, ex-aao-wconsj-0-svc-rte.

This procedure shows you how to access the AMQ Broker management console for a running broker instance.

Procedure

  1. In the OpenShift Container Platform web console, click NetworkingRoutes (OpenShift Container Platform 4.1) or ApplicationsRoutes (OpenShift Container Platform 3.11).

    On the Routes pane, you see a Route corresponding to the wconsj Service.

  2. Under Hostname, note the complete URL. You need to specify this URL to access the console.
  3. In a web browser, enter the host name URL.

    1. If your console configuration does not use SSL, specify http in the URL. In this case, DNS resolution of the host name directs traffic to port 80 of the OpenShift router.
    2. If your console configuration uses SSL, specify https in the URL. In this case, your browser defaults to port 443 of the OpenShift router. This enables a successful connection to the console if the OpenShift router also uses port 443 for SSL traffic, which the router does by default.
  4. To log in to the management console, enter the user name and password specified in the adminUser and adminPassword parameters of your broker deployment Custom Resource. If there are no values specified for adminUser and adminPassword, follow the instructions in Accessing management console login credentials to retrieve the credentials required to log in to the console.

2.6.2.2. Accessing management console login credentials

If you did not specify a value for adminUser and adminPassword in your broker Custom Resource (CR), the Operator automatically generates the broker user name and password (required to log in to the AMQ Broker management console) and stores these credentials in a secret. The default secret name has a format of <Custom Resource name>-credentials-secret, for example, ex-aao-credentials-secret.

This procedure shows you how to access the login credentials required to log in to the management console.

Procedure

  1. See the complete list of secrets in your OpenShift project.

    1. From the OpenShift Container Platform web console, click WorkloadSecrets (OpenShift Container Platform 4.1) or ResourcesSecrets (OpenShift Container Platform 3.11).
    2. From the command line:

      $ oc get secrets
  2. Open the appropriate secret to reveal the console login credentials.

    1. From the OpenShift Container Platform web console, click the secret that includes your broker Custom Resource instance in its name. To see the encrypted user name and password values, click the YAML tab (OpenShift Container Platform 4.1) or ActionsEdit YAML (OpenShift Container Platform 3.11).
    2. From the command line:

      $ oc edit secret <my_custom_resource_name-credentials-secret>

2.7. Broker deployment examples

2.7.1. Deploying clustered brokers

If there are two or more broker Pods running in your project, the Pods automatically form a broker cluster. A clustered configuration enables brokers to connect to each other and redistribute messages as needed, for load balancing.

The following procedure shows you how to deploy clustered brokers. By default, the brokers in this deployment use on demand load balancing, meaning that brokers will forward messages only to other brokers that have matching consumers.

Prerequisites

Procedure

  1. In the deploy/crs directory of the Operator archive that you downloaded and extracted, open the broker_v2alpha1_activemqartemis_cr.yaml Custom Resource file.
  2. For a minimally-sized clustered deployment, ensure that the value of deploymentPlan.size is 2.
  3. At the command line, apply the change:

    $ oc apply -f deploy/crs/broker_v2alpha1_activemqartemis_cr.yaml

    In the OpenShift Container Platform web console, a second Pod starts in your project, for the additional broker that you specified in your CR. By default, the two brokers running in your project are clustered.

  4. Open the Logs tab of each Pod. The logs show that OpenShift has established a cluster connection bridge on each broker. Specifically, the log output includes a line like the following:

    targetConnector=ServerLocatorImpl (identity=(Cluster-connection-bridge::ClusterConnectionBridge@6f13fb88

2.7.2. Creating queues in a broker cluster

The following procedure shows you how to use a Custom Resource Definition (CRD) and example Custom Resource (CR) to add and remove a queue from a broker cluster deployed using an Operator.

Prerequisites

Procedure

  1. Deploy the addressing CRD.

    $ oc create -f deploy/crds/broker_v2alpha1_activemqartemisaddress_crd.yaml
  2. An example CR file, broker_v2alpha1_activemqartemisaddress_cr.yaml, was included in the Operator archive that you downloaded and extracted. The example Custom Resource includes the following:

    spec:
      # Add fields here
      spec:
        addressName: myAddress0
        queueName: myQueue0
        routingType: anycast

    With your broker cluster already already deployed and running via the Operator, use the example Custom Resource to create an address on every running broker in your cluster.

    $ oc create -f deploy/crs/broker_v2alpha1_activemqartemisaddress_cr.yaml

    Deploying the example CR creates an address myAddress0 with a queue named myQueue0 that has an anycast routing type. This address is created on every running broker.

    Note

    To create multiple addresses and/or queues in your broker cluster, you need to create separate CR files and deploy them individually, specifying new address and/or queue names in each case.

    Note

    If you add brokers to your cluster after deploying the addressing CR, the new brokers will not have the address you previously created. In this case, you need to delete the addresses and redeploy the addressing CR.

  3. To delete queues created from the example CR, use the following command:

    $ oc delete -f deploy/crs/broker_v2alpha1_activemqartemisaddress_cr.yaml

2.8. Migrating messages upon scaledown

To migrate messages upon scaledown of your broker deployment, use the main broker Custom Resource Definition (CRD) to enable message migration. The AMQ Broker Operator runs a dedicated scaledown controller to execute message migration when you scale down a clustered broker deployment.

With message migration enabled, the scaledown controller within the Operator detects shutdown of a broker Pod and starts a drainer Pod to execute message migration. The drainer Pod connects to one of the other live broker Pods in the cluster and migrates messages over to that live broker Pod. After migration is complete, the scaledown controller shuts down.

Note

A scaledown controller operates only within a single OpenShift project. The controller cannot migrate messages between brokers in separate projects.

Note

If you scale a broker deployment down to 0 (zero), message migration does not occur, since there is no running broker Pod to which the messaging data can be migrated. However, if you scale a deployment down to zero brokers and then back up to only some of the brokers that were in the original deployment, drainer Pods are started for the brokers that remain shut down.

The following example procedure shows the behavior of the scaledown controller.

Prerequisites

Procedure

  1. In the deploy/crs directory of the Operator repository that you originally downloaded and extracted, open the main broker CR, broker_v2alpha1_activemqartemis_cr.yaml.
  2. In the main broker CR set messageMigration and persistenceEnabled to true.

    These settings mean that when you later scale down the size of your clustered broker deployment, the Operator automatically starts a scaledown controller and migrate messages to a broker Pod that is still running.

  3. In your existing broker deployment, verify which Pods are running.

    $ oc get pods

    You see output that looks like the following.

    activemq-artemis-operator-8566d9bf58-9g25l   1/1   Running   0   3m38s
    ex-aao-ss-0                                  1/1   Running   0   112s
    ex-aao-ss-1                                  1/1   Running   0   8s

    The preceding output shows that there are three Pods running; one for the broker Operator itself, and a separate Pod for each broker in the deployment.

  4. Log into each Pod and send some messages to each broker.

    1. Supposing that Pod ex-aao-ss-0 has a cluster IP address of 172.17.0.6, run the following command:

      $ /opt/amq-broker/bin/artemis producer --url tcp://172.17.0.6:61616 --user admin --password admin
    2. Supposing that Pod ex-aao-ss-1 has a cluster IP address of 172.17.0.7, run the following command:

      $ /opt/amq-broker/bin/artemis producer --url tcp://172.17.0.7:61616 --user admin --password admin

      The preceding commands create a queue called TEST on each broker and add 1000 messages to each queue.

  5. Scale the cluster down from two brokers to one.

    1. Open the main broker CR, broker_v2alpha1_activemqartemis_cr.yaml.
    2. In the CR, set deploymentPlan.size to 1.
    3. At the command line, apply the change:

      $ oc apply -f deploy/crs/broker_v2alpha1_activemqartemis_cr.yaml

      You see that the Pod ex-aao-ss-1 starts to shut down. The scaledown controller starts a new drainer Pod of the same name. This drainer Pod also shuts down after it migrates all messages from broker Pod ex-aao-ss-1 to the other broker Pod in the cluster, ex-aao-ss-0.

  6. When the drainer Pod is shut down, check the message count on the TEST queue of broker Pod ex-aao-ss-0. You see that the number of messages in the queue is 2000, indicating that the drainer Pod successfully migrated 1000 messages from the broker Pod that shut down.

2.9. Managing the Broker Operator using the Operator Lifecycle Manager

2.9.1. Overview of the Operator Lifecycle Manager

In OpenShift Container Platform 4.0 and later, the Operator Lifecycle Manager (OLM) helps users install, update, and generally manage the lifecycle of all Operators and their associated services running across their clusters. It is part of the Operator Framework, an open source toolkit designed to manage Kubernetes native applications (Operators) in an effective, automated, and scalable way.

The OLM runs by default in OpenShift Container Platform 4.0, which aids cluster administrators in installing, upgrading, and granting access to Operators running on their cluster. The OpenShift Container Platform web console provides management screens for cluster administrators to install Operators, as well as grant specific projects access to use the catalog of Operators available on the cluster.

OperatorHub is the graphical interface that OpenShift cluster administrators use to discover, install, and upgrade Operators. With one click, these Operators can be pulled from OperatorHub, installed on the cluster, and managed by the OLM, ready for engineering teams to self-service manage the software in development, test, and production environments.

When you install the AMQ Broker Operator in OperatorHub, you can use the graphical interface to create various broker deployments, such as standalone and clustered brokers.

2.9.2. Installing the AMQ Broker Operator in OperatorHub

If you do not see the AMQ Broker Operator automatically available for use in OperatorHub, follow these instructions to manually install the Operator.

Procedure

  1. In your web browser, navigate to the AMQ Broker Software Downloads page.
  2. In the Version drop-down box, ensure the value is set to the latest Broker version, 7.5.0.
  3. Next to AMQ Broker 7.5 Operator Installation Files, click Download.

    Download of the amq-broker-operator-7.5.0-ocp-install-examples.zip compressed archive automatically begins.

  4. When the download has completed, move the archive to your chosen installation directory. The following example moves the archive to a directory called /broker/operator.

    sudo mv amq-broker-operator-7.5.0-ocp-install-examples.zip /broker/operator
  5. In your chosen installation directory, extract the contents of the archive. For example:

    cd /broker/operator
    unzip amq-broker-operator-7.5.0-ocp-install-examples.zip
  6. Log in to OpenShift Container Platform as a cluster administrator.

    $ oc login -u system:admin
  7. Deploy the AMQ Broker Operator source bundle from the deploy directory of the Operator archive that you downloaded and extracted.

    $ oc create -f deploy/catalog_resources/courier/amq-broker-operatorsource.yaml

    After a few minutes, the AMQ Broker Operator is available in the OperatorHub section of the OpenShift Container Platform web console. You can then use the OperatorHub graphical interface to create various types of broker deployments.