This app shows off the features of an Immutant cluster, specifically:
- Load-balanced messaging with automatic peer discovery
- HA singleton daemons
- HA singleton jobs
- Cache and web session replication
All the code is in src/immutant/init.clj. A simple web app is
included that returns the contents of the distributed cache. When
fronted by a round-robin, HTTP reverse-proxy, the data should remain
consistent and available as long as at least one cluster node is up.
You can view all components of the app by "tailing" the
standalone/logs/server.log beneath $IMMUTANT_HOME on each node.
Failover for jobs and daemons can be observed by killing whichever Immutant is running the job or daemon. This should result in the immediate migration of those services to another node in the cluster automatically.
Form a cluster of Immutants by running the following on each node:
$ lein immutant run --clustered
Deploy the app to each Immutant
$ lein immutant deploy
Copyright © 2013 Jim Crossley
Distributed under the Eclipse Public License, the same as Clojure.