WebSphere Liberty on IBM Containers: Part 2

Deploying an Application

In the first part of this series we looked at how to get started running a WebSphere Liberty image in IBM Containers using the Bluemix console.  The container was just running an empty Liberty server. In this post we’ll look at building and deploying an image that adds an application. I was originally intending to stick to using the browser for this post but I think it’s actually easier to do this from the command line. I’m going to assume that you already have Docker installed locally, either natively on Linux, via Docker Machine, or via the Docker for Mac/Windows beta.

First off we need an application to deploy and, just for novelty, I’m going to use the Liberty app accelerator to generate one. Select Servlet as the technology type and then, contrary as it may seem, select Deploy to Local and not Deploy to Bluemix. The latter option currently only supports deploying to the Instant Runtimes (Cloud Foundry) side of Bluemix. Finally, give your project a name and click Download Now.

Liberty App Accelerator

Unpack the zip file you downloaded and change to the top directory of the project. The app is built using maven. Perhaps you already have maven installed but this is a Docker blog post so we’re going to use the maven image from Docker Hub to build the app as follows:

$ docker run –rm -v $(pwd):/usr/src/mymaven \
    -w /usr/src/mymaven/myProject-application maven mvn clean package

This mounts the project on to a container running the maven image and runs the command mvn clean package in the myProject-application directory. Note: if you were doing this repeatedly you’d probably want to mount a maven cache in to the image as well and not download everything each time)

In the myProject-application/target directory you should now find that you have a file myArtifactId-application-1.0-SNAPSHOT.war. Copy this in to a new empty directory so that when we execute a Docker build we don’t end up uploading lots of other cruft to the Docker engine. Using your favourite editor, add the following Dockerfile to the same directory:

FROM websphere-liberty:webProfile7
COPY myArtifactId-application-1.0-SNAPSHOT.war /config/dropins

We have two choices now, we can either build a Docker image locally and then push that up to the IBM Containers registry, or we can build the image in IBM Containers. We’ll go for the latter option here as it involves pushing less bytes over the network.

There’s one niggle today that, to access your IBM Containers registry, you need to log in first using the Cloud Foundry CLI and IBM Containers plugin. We’re going to play the containerisation trick again here. Run the following commands to build an image with the CLI and plugin:

$ docker build -t cf https://git.io/vr7pl

Ideally I’d run this image as a stateless container but getting the right state written out to host in to the .cf, .ice and .docker directories is a bit finicky. Instead, we’re going to mount our current directory on to an instance of the image and perform the build inside:

$ docker run -it –rm $(pwd):/root/build cf
$ cd /root/build
$ cf login -a api.ng.bluemix.net

$ cf ic login
$ cf ic build -t demo .

Now we’re ready to run an instance of your newly built image. At this point you could switch back the to the UI but lets keep going with the command line. We’ll need to refer to the built image using the full repository name, including your namespace:

$ ns=$(cf ic namespace get)
$ cf ic run –name demo -P registry.ng.bluemix.net/$ns/demo

By default, containers are only assigned a private IP address. In order to access our new container we’ll need to request and assign a public IP. The cf ic ip command unfortunately returns a human friendly message, not a computer friendly one, hence the need for the grep/sed to retrieve the actual IP:

$ ip=$(cf ic ip request | grep -o ‘”.*”‘ | sed ‘s/”//g’)
$ cf ic ip bind $ip demo

Lastly, we can list the port and IP to point our browser at:

$ cf ic port demo 9080

Adding the root context myLibertyApp should give use the welcome page for the starter app.

Starter Welcome Page

Congratulations, you’ve successfully deployed an application to IBM Containers! In the next post in this series we’ll look at some of the additional features that the service provides, such as scaling groups and logging.

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