Using Docker to deal with a TomEE missing feature

When I and Bruno Souza were writing the article “Step-by-Step High Availability with Docker and Java EE” we faced a little issue with an Apache TomEE cluster feature: the “hot” deployment thru the cluster nodes isn’t still available, although the configuration at the server.xml is already defined:

<Deployer
className=”org.apache.catalina.ha.deploy.FarmWarDeployer”
deployDir=”/tmp/war-deploy/”
tempDir=”/tmp/war-temp/”
watchDir=”/tmp/war-listen/”
watchEnabled=”true”/>

The point is: if you deploy a new version of your application in one node, it doesn’t spread thru your entire cluster. At the first moment we look at this as some kind of a tricky situation that we must deal with.

But talking for just a few moments we realized that the article purpose itself was the answer for that issue! How? Simple…

When we create an appliance (for the definition, take a look at the article) we already have the application deployed to our application server. So when we use this appliance to build our cluster (running multiple Docker instances with properly configurations) we don’t need any other deployment at all!

Containers to the rescue! 😉