Running Infinispan cluster on OpenShift

Did you know that it's extremely easy to run Infinispan in OpenShift? Infinispan 9.0.0.Alpha4 adds out of the box support for OpenShift (and Kubernetes) discovery!

Our goal

We'd like to build an Infinispan cluster on top of OpenShift and expose a Service for it (you may think about Services as Load Balancers). A Service can be exposed to the outside world using Routes. Finally, we will use REST interface to PUT and GET some data from the cluster.

Accessing the OpenShift cloud

Of course before playing with Infinispan, you will need an OpenShift cluster. There are number of options you can investigate. I will use the simplest path - OpenShift local cluster.

The first step is to download OpenShift Client Tools for your platform. You can find them on OpenShift releases Github page. Once you download and extract the 'oc' binary, make it accessible in your $PATH. I usually copy such things into my '/usr/bin' directory (I'm using Fedora F23). 

Once everything is set and done - spin up the cluster:

	$ oc cluster up
	-- Checking Docker client ... OK
	-- Checking for existing OpenShift container ... OK
	-- Checking for openshift/origin:latest image ... OK
	-- Checking Docker daemon configuration ... OK
	-- Checking for available ports ...
	WARNING: Binding DNS on port 8053 instead of 53, which may be not be resolvable from all clients.
	-- Checking type of volume mount ...
	Using nsenter mounter for OpenShift volumes
	-- Checking Docker version ... OK
	-- Creating volume share ... OK
	-- Finding server IP ...
	Using 192.168.0.17 as the server IP
	-- Starting OpenShift container ...
	Creating initial OpenShift configuration
	Starting OpenShift using container 'origin'
	Waiting for API server to start listening
	OpenShift server started
	-- Installing registry ... OK
	-- Installing router ... OK
	-- Importing image streams ... OK
	-- Importing templates ... OK
	-- Login to server ... OK
	-- Creating initial project "myproject" ... OK
	-- Server Information ...
	OpenShift server started.
	The server is accessible via web console at:
	https://192.168.0.17:8443
	You are logged in as:
	User: developer
	Password: developer
	To login as administrator:
	oc login -u system:admin

view raw Starting an OpenShift Local Cluster hosted with ❤ by GitHub

Note that you have been automatically logged in as 'developer' and your project has been automatically set to 'myproject'. 

Spinning an Infinispan cluster

The first step is to create an Infinispan app:

	$ oc new-app jboss/infinispan-server
	--> Found Docker image 9f3d9bf (13 minutes old) from Docker Hub for "jboss/infinispan-server"
	* An image stream will be created as "infinispan-server:latest" that will track this image
	* This image will be deployed in deployment config "infinispan-server"
	* Ports 11211/tcp, 11222/tcp, 57600/tcp, 7600/tcp, 8080/tcp, 8181/tcp, 8888/tcp, 9990/tcp will be load balanced by service "infinispan-server"
	* Other containers can access this service through the hostname "infinispan-server"
	--> Creating resources with label app=infinispan-server ...
	imagestream "infinispan-server" created
	deploymentconfig "infinispan-server" created
	service "infinispan-server" created
	--> Success
	Run 'oc status' to view your app.

view raw Infinispan app hosted with ❤ by GitHub

Now you need to modify the Deployment Configuration (use 'oc edit dc/infinispan-server' for this) and tell Infinispan to boot up with Kubernetes' discovery protocol stack by using the proper namespace to look up other nodes (unfortunately this step can not be automated, otherwise a newly created Infinispan node might try to join an existing cluster and this is something you might not want). Here's my modified Deployment Configuration:

	apiVersion: v1
	kind: DeploymentConfig
	metadata:
	name: infinispan-server
	namespace: myproject
	selfLink: /oapi/v1/namespaces/myproject/deploymentconfigs/infinispan-server
	uid: eaf22ecc-5afa-11e6-bcb7-54ee751d46e3
	resourceVersion: '865'
	generation: 6
	creationTimestamp: '2016-08-05T10:54:01Z'
	labels:
	app: infinispan-server
	annotations:
	openshift.io/generated-by: OpenShiftNewApp
	spec:
	strategy:
	type: Rolling
	rollingParams:
	updatePeriodSeconds: 1
	intervalSeconds: 1
	timeoutSeconds: 600
	maxUnavailable: 25%
	maxSurge: 25%
	resources:
	triggers:
	-
	type: ConfigChange
	-
	type: ImageChange
	imageChangeParams:
	automatic: true
	containerNames:
	- infinispan-server
	from:
	kind: ImageStreamTag
	namespace: myproject
	name: 'infinispan-server:latest'
	lastTriggeredImage: 'jboss/infinispan-server@sha256:52b4fcb1530159176ceb81ea8d9638fa69b8403c8ca5ac8aea1cdbcb645beb9a'
	replicas: 1
	test: false
	selector:
	app: infinispan-server
	deploymentconfig: infinispan-server
	template:
	metadata:
	creationTimestamp: null
	labels:
	app: infinispan-server
	deploymentconfig: infinispan-server
	annotations:
	openshift.io/container.infinispan-server.image.entrypoint: '["docker-entrypoint.sh"]'
	openshift.io/generated-by: OpenShiftNewApp
	spec:
	containers:
	-
	name: infinispan-server
	image: 'jboss/infinispan-server@sha256:52b4fcb1530159176ceb81ea8d9638fa69b8403c8ca5ac8aea1cdbcb645beb9a'
	args:
	- cloud
	- '-Djboss.default.jgroups.stack=kubernetes'
	ports:
	-
	containerPort: 8181
	protocol: TCP
	-
	containerPort: 8888
	protocol: TCP
	-
	containerPort: 9990
	protocol: TCP
	-
	containerPort: 11211
	protocol: TCP
	-
	containerPort: 11222
	protocol: TCP
	-
	containerPort: 57600
	protocol: TCP
	-
	containerPort: 7600
	protocol: TCP
	-
	containerPort: 8080
	protocol: TCP
	env:
	-
	name: OPENSHIFT_KUBE_PING_NAMESPACE
	valueFrom: {fieldRef: {apiVersion: v1, fieldPath: metadata.namespace}}
	resources:
	terminationMessagePath: /dev/termination-log
	imagePullPolicy: Always
	restartPolicy: Always
	terminationGracePeriodSeconds: 30
	dnsPolicy: ClusterFirst
	securityContext:
	status:
	latestVersion: 5
	observedGeneration: 6
	replicas: 1
	updatedReplicas: 1
	availableReplicas: 1
	details:
	causes:
	-
	type: ConfigChange

view raw Deployment Configuration hosted with ❤ by GitHub

• (lines 58-60) - Modified Infinispan startup parameters by adding image startup arguments.
• (lines 88-90) - JGroups Kubernetes Discovery protocol is instrumented by the Downward API to use current project's namespace. 

There is one final step - Kubernetes' PING protocol uses the API to look up other nodes in the Infinispan cluster. By default API access is disabled in OpenShift and needs to be enabled. This can be done by this simple command:

$ oc policy add-role-to-user view system:serviceaccount:$(oc project -q):default -n $(oc project -q)

view raw Accessing OpenShift API from the Pods hosted with ❤ by GitHub

Now we can redeploy the application (to ensure that all changes were applied) and scale it out (to 3 nodes):

	$ oc deploy infinispan-server --latest -n myproject
	$ oc scale --replicas=3 dc/infinispan-server
	deploymentconfig "infinispan-server" scaled

view raw Scaling the cluster out hosted with ❤ by GitHub

Now let's check if everything looks good - you can do it either through the OpenShift web console or by using 'oc get pods' and 'oc logs' commands:

	$ oc logs infinispan-server-6-lfiy9 | grep -i "Received new cluster view"
	11:45:58,151 INFO [org.infinispan.remoting.transport.jgroups.JGroupsTransport] (Incoming-2,infinispan-server-6-lfiy9) ISPN000094: Received new cluster view for channel clustered: [infinispan-server-6-lfiy9|8] (3) [infinispan-server-6-lfiy9, infinispan-server-6-07vtk, infinispan-server-6-6ts14]

view raw Validating cluster view hosted with ❤ by GitHub

Accessing the cluster

In order to access the Infinispan cluster from the outside world we need a Route:

	$ oc expose svc/infinispan-server
	route "infinispan-server" exposed

view raw Creating a route hosted with ❤ by GitHub

The newly created Route needs small changes - we need to change the target port to 8080 (this is the REST service). The 'oc edit route/infinispan-server' command is perfect for it. Below is my updated configuration:

	apiVersion: v1
	kind: Route
	metadata:
	annotations:
	openshift.io/host.generated: "true"
	creationTimestamp: 2016-08-05T11:57:14Z
	labels:
	app: infinispan-server
	name: infinispan-server
	namespace: myproject
	resourceVersion: "1373"
	selfLink: /oapi/v1/namespaces/myproject/routes/infinispan-server
	uid: c00bf8b5-5b03-11e6-bcb7-54ee751d46e3
	spec:
	host: infinispan-server-myproject.192.168.0.17.xip.io
	port:
	targetPort: 8080-tcp
	to:
	kind: Service
	name: infinispan-server
	status:
	ingress:
	- conditions:
	- lastTransitionTime: 2016-08-05T11:57:14Z
	status: "True"
	type: Admitted
	host: infinispan-server-myproject.192.168.0.17.xip.io
	routerName: router

view raw Updated Route hosted with ❤ by GitHub

• (line 17) - Modified to 8080 TCP port

Testing the setup

You can easily see how to access the cluster by describing the Route:

	$ oc get route/infinispan-server 1 ↵
	NAME HOST/PORT PATH SERVICE TERMINATION LABELS
	infinispan-server infinispan-server-myproject.192.168.0.17.xip.io infinispan-server:7600-tcp app=infinispan-server%

view raw Viewing routes hosted with ❤ by GitHub

Now let's try to play with the data:

	$ curl -X POST -H 'Content-type: text/plain' -d 'test' infinispan-server-myproject.192.168.0.17.xip.io/rest/default/test
	$ curl -X GET -H 'Content-type: text/plain' infinispan-server-myproject.192.168.0.17.xip.io/rest/default/test
	test%

view raw Adding and retrieving data from the cache hosted with ❤ by GitHub

Cleaning up

Finally, when you are done with experimenting, you can remove everything using 'oc delete' command:

	$ oc delete all -l "app=infinispan-server"
	imagestream "infinispan-server" deleted
	deploymentconfig "infinispan-server" deleted
	route "infinispan-server" deleted
	service "infinispan-server" deleted
	pod "infinispan-server-6-4fdvm" deleted
	pod "infinispan-server-6-z686g" deleted

view raw Removing the application hosted with ❤ by GitHub

Conclusion

Running Infinispan cluster inside an OpenShift cloud is really simple. Just 3 steps to remember:

1. Create an Infinispan app ('oc new-app')
2. Tell it to use Kubernetes JGroups Stack and in which project look for other cluster members ('oc edit dc/infinispan-server')
3. Allow access to the OpenShift API ('oc policy add-role-to-user')

Happy scaling!