Bundle Hazelcast and your dependencies into a system service

Hazelcast is an awesome middleware providing distributed data structures, caching, pub/sub mechanisms and much more.

It is perfectly possible to just download its distribution and start a node via java -jar ... pointing it to your configuration etc.

This (maven) project takes an alternative approach and builds a zipfile bundling Hazelcast (and other) dependencies, a directory structure for libs, configs, etc. and SLF4J based logging using logback as the underlying implementation.

Motivation

The idea is to be able to run a cluster node as a UNIX init.d script that can be start-ed and stop-ed and put into a OS startup process via update-rd.d (Debian based distros) or a similar tool.

There is also a convenient feature: for several usages such as IMap, IQueue, Topic, etc. a Hazelcast node does not need to "know" the java classes used because it all works via serialisation. For example, if you are using Hazelcast nodes as a shared cache implementation, only clients need to have the data classes in their classpath, not the cluster nodes themselves.

However, for other usages such as Distributed Executor Service or Map Reduce, your code submitted to the cluster (JVM) may need to know the classes at hand. If you are using maven for the rest of your build the convenience here is that you can just add whichever of your other dependencies to the POM as runtime dependencies and that'll make nodes started with this project be able to use these classes.

Building

You'll need JDK 8 and a recent stable version of maven in your path. I am using the latest version of Hazelcast at the time of publishing (3.6.3) but that should be easily changed in the hazelcast.version POM property.

If you cannot use Java 8 it should not be difficult to port the code to an older version; I am not using many new features other than the java.time API.

So just:

$ cd hazelcast-manager
$ mvn clean install

You'll find the zipped bundle in hazelcast/target/hazelcast-manager-<version>-bin.zip, comprising the following directories:

• bin/: UNIX and Windows launcher script and other native dependencies to support the "system service" features.
• lib/: This is where Hazelcast's and your own jars, together with other dependencies are saved.
• logs/: Plain empty directory where the distribution will log to by default.
• etc/: Directory for all configuration files (Hazelcast, logging and system service). These will be explained next.

Configuration and Usage

You can use this project to start several nodes pointing to specific XML configuration file(s). In order to selectively stop a node you need to assign different names to each node via the -name command line option.

Every started node listens on a Topic named after -mgmnt-topic for a quit message. When the information in this message includes a specific node -name, it will itself terminate.

You can look into the Starter and Quitter classes (and the BaseCommand parent for both to find out the specific parameters for starting and terminating a node, respectively.

What I do is just symlink bin/hazelcast-manager into my server's /etc/init.d directory and then use udate-rc.d to configure its runlevels.

The configuration used for the system service is built via the <configuration/> section of the appassembler-maven-plugin in the POM. This ends up in the etc/wrapper-hazelcast-manager.conf file bundled in the final zipfile and can also be edited directly in that file for other deployments.

Final

If you are interested in using this feature project and would like more information please sure file an issue and I will be glad to help!