Chapter 3. Accessing ActiveMQ using Skupper Use public cloud resources to process data from a private message broker This example is part of a suite of examples showing the different ways you can use Skupper to connect services across cloud providers, data centers, and edge sites. Overview This example is a simple messaging application that shows how you can use Skupper to access an ActiveMQ broker at a remote site without exposing it to the public internet. It contains two services: An ActiveMQ broker running in a private data center. The broker has a queue named "notifications". An AMQP client running in the public cloud. It sends 10 messages to "notifications" and then receives them back. For the broker, this example uses the Apache ActiveMQ Artemis image from ArtemisCloud.io . The client is a simple Quarkus application. The example uses two Kubernetes namespaces, "private" and "public", to represent the private data center and public cloud. Prerequisites The kubectl command-line tool, version 1.15 or later ( installation guide ) Access to at least one Kubernetes cluster, from any provider you choose Procedure Clone the repo for this example. Install the Skupper command-line tool Set up your namespaces Deploy the message broker Create your sites Link your sites Expose the message broker Run the client Clone the repo for this example. Navigate to the appropriate GitHub repository from https://skupper.io/examples/index.html and clone the repository. Install the Skupper command-line tool This example uses the Skupper command-line tool to deploy Skupper. You need to install the skupper command only once for each development environment. See the Installation for details about installing the CLI. For configured systems, use the following command: Set up your namespaces Skupper is designed for use with multiple Kubernetes namespaces, usually on different clusters. The skupper and kubectl commands use your kubeconfig and current context to select the namespace where they operate. Your kubeconfig is stored in a file in your home directory. The skupper and kubectl commands use the KUBECONFIG environment variable to locate it. A single kubeconfig supports only one active context per user. Since you will be using multiple contexts at once in this exercise, you need to create distinct kubeconfigs. For each namespace, open a new terminal window. In each terminal, set the KUBECONFIG environment variable to a different path and log in to your cluster. Then create the namespace you wish to use and set the namespace on your current context. Note The login procedure varies by provider. See the documentation for yours: Amazon Elastic Kubernetes Service (EKS) Azure Kubernetes Service (AKS) Google Kubernetes Engine (GKE) IBM Kubernetes Service OpenShift Public: Private: Deploy the message broker In Private, use the kubectl apply command to install the broker. Private: Sample output: Create your sites A Skupper site is a location where components of your application are running. Sites are linked together to form a network for your application. In Kubernetes, a site is associated with a namespace. For each namespace, use skupper init to create a site. This deploys the Skupper router and controller. Then use skupper status to see the outcome. Public: Sample output: Private: Sample output: As you move through the steps below, you can use skupper status at any time to check your progress. Link your sites A Skupper link is a channel for communication between two sites. Links serve as a transport for application connections and requests. Creating a link requires use of two skupper commands in conjunction, skupper token create and skupper link create . The skupper token create command generates a secret token that signifies permission to create a link. The token also carries the link details. Then, in a remote site, The skupper link create command uses the token to create a link to the site that generated it. Note The link token is truly a secret. Anyone who has the token can link to your site. Make sure that only those you trust have access to it. First, use skupper token create in site Public to generate the token. Then, use skupper link create in site Private to link the sites. Public: Sample output: Private: Sample output: If your terminal sessions are on different machines, you may need to use scp or a similar tool to transfer the token securely. By default, tokens expire after a single use or 15 minutes after creation. Expose the message broker In Private, use skupper expose to expose the broker on the Skupper network. Then, in Public, use kubectl get service/broker to check that the service appears after a moment. Private: Sample output: Public: Sample output: Run the client In Public, use kubectl run to run the client. Public: Sample output:

Commands:
sudo dnf install skupper-cli
export KUBECONFIG=~/.kube/config-public Enter your provider-specific login command create namespace public config set-context --current --namespace public
export KUBECONFIG=~/.kube/config-private Enter your provider-specific login command create namespace private config set-context --current --namespace private
apply -f server
kubectl apply -f server deployment.apps/broker created
skupper init skupper status
skupper init Waiting for LoadBalancer IP or hostname Waiting for status Skupper is now installed in namespace 'public'. Use 'skupper status' to get more information. skupper status Skupper is enabled for namespace "public". It is not connected to any other sites. It has no exposed services.
skupper init skupper status
skupper init Waiting for LoadBalancer IP or hostname Waiting for status Skupper is now installed in namespace 'private'. Use 'skupper status' to get more information. skupper status Skupper is enabled for namespace "private". It is not connected to any other sites. It has no exposed services.
skupper token create ~/secret.token
skupper token create ~/secret.token Token written to ~/secret.token
skupper link create ~/secret.token
skupper link create ~/secret.token Site configured to link to https://10.105.193.154:8081/ed9c37f6-d78a-11ec-a8c7-04421a4c5042 (name=link1) Check the status of the link using 'skupper link status'.
skupper expose deployment/broker --port 5672
skupper expose deployment/broker --port 5672 deployment broker exposed as broker
get service/broker
kubectl get service/broker NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE broker ClusterIP 10.100.58.95 <none> 5672/TCP 2s
run client --attach --rm --restart Never --image quay.io/skupper/activemq-example-client --env SERVER=broker
kubectl run client --attach --rm --restart Never --image quay.io/skupper/activemq-example-client --env SERVER=broker ____ __ _____ ___ __ ____ ____ --/ __ \/ / / / _ | / _ \/ //_/ / / / / -/ /_/ / /_/ / __ |/ , / ,< / // /\ --\___\_\____/_/ |_/_/|_/_/|_|\____/_/ 2022-05-27 11:19:07,149 INFO [io.sma.rea.mes.amqp] (main) SRMSG16201: AMQP broker configured to broker:5672 for channel incoming-messages 2022-05-27 11:19:07,170 INFO [io.sma.rea.mes.amqp] (main) SRMSG16201: AMQP broker configured to broker:5672 for channel outgoing-messages 2022-05-27 11:19:07,198 INFO [io.sma.rea.mes.amqp] (main) SRMSG16212: Establishing connection with AMQP broker 2022-05-27 11:19:07,212 INFO [io.sma.rea.mes.amqp] (main) SRMSG16212: Establishing connection with AMQP broker 2022-05-27 11:19:07,215 INFO [io.quarkus] (main) client 1.0.0-SNAPSHOT on JVM (powered by Quarkus 2.9.2.Final) started in 0.397s. 2022-05-27 11:19:07,215 INFO [io.quarkus] (main) Profile prod activated. 2022-05-27 11:19:07,215 INFO [io.quarkus] (main) Installed features: [cdi, smallrye-context-propagation, smallrye-reactive-messaging, smallrye-reactive-messaging-amqp, vertx] Sent message 1 Sent message 2 Sent message 3 Sent message 4 Sent message 5 Sent message 6 Sent message 7 Sent message 8 Sent message 9 Sent message 10 2022-05-27 11:19:07,434 INFO [io.sma.rea.mes.amqp] (vert.x-eventloop-thread-0) SRMSG16213: Connection with AMQP broker established 2022-05-27 11:19:07,442 INFO [io.sma.rea.mes.amqp] (vert.x-eventloop-thread-0) SRMSG16213: Connection with AMQP broker established 2022-05-27 11:19:07,468 INFO [io.sma.rea.mes.amqp] (vert.x-eventloop-thread-0) SRMSG16203: AMQP Receiver listening address notifications Received message 1 Received message 2 Received message 3 Received message 4 Received message 5 Received message 6 Received message 7 Received message 8 Received message 9 Received message 10 Result: OK