We are going to Containerize all services and run them on Openshift. Running a set of related services on Kubernetes or Openshift usually requires some additional work, but there are tools that make your life really easy and we're going to use them.
Note: refer to the first part of the tutorial for installation instructions
of Minishift and the oc binary.
Ensure all services are not running, since the operations we are going to do next will start again all services on the local Minishift (you should not have infinite resources on your laptop).
To start Minishift execute the following command:
minishift start
Usually you're logged in into the cluster, but in case your credential are expired you can use the following command to login again:
oc login https://$(minishift ip):8443
# then use `developer` as user and `x` as password (any password is ok)
Minishift usually creates a default project called myproject.
A project is a private namespace where you can deploy related services running as containers.
We are going to create a new project for our workshop:
oc new-project workshop
The oc binary is now also configured to use the workshop project by default. You can check what's inside the project by using:
oc get all
You can see what will happen next from a graphical user interface.
Type the following on the terminal:
minishift console
Your browser will open the Openshift console corresponding to the Minishift instance.
Login with the same credentials used before and navigate to the workshop project (that should be empty).
Let's start adding a plugin to to deploy all services on Openshift. We'll do it first for credit, inventory and recommendation, then we'll do a customized configuration for the gateway.
In the pom.xml file of credit, inventory and recommendation add the following declaration at the end of the file (right before the </project> closing tag):
<profiles>
<profile>
<id>openshift</id>
<build>
<plugins>
<plugin>
<groupId>io.fabric8</groupId>
<artifactId>fabric8-maven-plugin</artifactId>
<version>3.5.39</version>
<executions>
<execution>
<goals>
<goal>resource</goal>
<goal>build</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</profile>
</profiles>It adds a profile called "openshift" that, when activated, binds the "fabric8-maven-plugin" to the build lifecycle of each project.
After adding the profile declaration, execute the following command to containerize each service and run it on Openshift (execute it 3 times, from the root of the credit, inventory and recommendation services respectively):
mvn clean fabric8:deploy -P openshift
With this simple command:
- The service is packaged into a container image with a Java base image customized for Camel Spring-Boot applications
- The image is pushed into the Openshift internal registry
- A Openshift Deployment is created, referencing the application image
- A Openshift Pod with a single container is created automatically by Openshift
- Openshift then starts the container with our app running inside
After you execute the command for all 3 services, look at the Openshift console, you should see that all services are running.
The gateway service requires a bit of configuration of the Fabric8 maven plugin.
Add the following declaration to the pom.xml file of the gateway service (right before the </project> closing tag):
<profiles>
<profile>
<id>openshift</id>
<build>
<plugins>
<plugin>
<groupId>io.fabric8</groupId>
<artifactId>fabric8-maven-plugin</artifactId>
<version>3.5.39</version>
<executions>
<execution>
<goals>
<goal>resource</goal>
<goal>build</goal>
</goals>
</execution>
</executions>
<configuration>
<resources>
<env>
<INVENTORY_SERVICE>inventory:8081</INVENTORY_SERVICE>
<CREDIT_SERVICE>credit:8082</CREDIT_SERVICE>
<RECOMMENDATION_SERVICE>recommendation:8083</RECOMMENDATION_SERVICE>
</env>
</resources>
</configuration>
</plugin>
</plugins>
</build>
</profile>
</profiles>It's the same as for the other services, but we ask the plugin to set 3 environment variables in the container.
That variables are meant to override the service settings in the application.properties file.
E.g. the INVENTORY_SERVICE environment variable in the container will replace the inventory.service property in application.properties file.
This way of overriding properties in containers is very common and can be used for general purpose configuration too. Naming conventions are described in the spring-boot externalized configuration guide.
Note: From Camel 2.21.2 the ServiceCall EIP has been enhanced to support natively Kubernetes and Openshift. Overriding the target URL of the services will not be necessary, since the ServiceCall EIP implementation in camel-kubernetes will auto-discover them.
To deploy the gateway service you can run the same command that you used for the other services:
mvn clean fabric8:deploy -P openshift
You should see it running.
The UI has been prepackaged into a docker container image and pushed to Docker Hub under the name nferraro/camel-workshop-ui:latest.
Openshift resources have already been prepared for the UI container. You can download the Openshift files from here (right click, save as...): openshift-ui.yaml
Put it somewhere in your file system and, from the dir where the file is located, in the terminal execute the following command:
oc create -f openshift-ui.yaml
This will create all Openshift resources to run the UI. The docker image will be downloaded by Openshift from Docker Hub and executed.
The yaml file defines also a Openshift Route that allows you to open the UI in a browser.
The URL is displayed in the Openshift console overview, next to the UI deployment you've just created.
Click on the UI link, you should be able to see the full containerized system running on Openshift.
Camel and Spring-Boot declare some health checks that tell the cloud platform if the pod is running correctly.
If the pod does not start or has some misconfiguration, for example, one might want to fix the problem before the application is running in production.
Health checks are activated automatically if you include in your application the Spring-Boot actuator module. The Fabric8 Maven Plugin detects this configuration and add readiness and liveness probes into the Openshift resources.
All you need to do is to add the following dependency in the pom.xml file of the services.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>Version is resolved by the spring-boot parent project.
You can now redeploy each service using the usual command:
mvn clean fabric8:deploy -P openshift
You'll notice that Openshift does a rolling upgrade of the pods, but it does not replace the old pods until the application is fully started without issues, thanks to checks embedded by Camel and Spring-Boot into the actuator module.
The new application is marked with light-blue color before it's fully running, then it becomes dark-blue.