On July 7th, I did a webinar on mod-cluster, and it was a huge success: 1215 people signed up and 544 attended the webinar ! I'm told that this is the second highest turnout ever for Red Hat (the highest being an xvirt webinar a couple of years ago, with 600 attendees)...
For those who missed the webex presentation, here's the link to the recorded video. For those who only want to see the demo, it is here.
The demo is really cool: I set up a huge cluster in the cloud, spanning GoGrid, EC2 and Rackspace as clouds, and fronting a JBoss 6 based cluster with mod-cluster.
I showed how cluster nodes dynamically register themselves with httpd, or de-register when shutting down, and how web applications get registered/de-registered.
For those who know mod-jk: no more workers.properties or uriworkmap.properties are needed !
The coolest part was where I ran a load test, simulating 80 clients, each creating and destroying a session every 30 seconds: initially I ran 2 cluster nodes on EC2, so every node had 40 sessions on average. Then I started another EC2 instance, a GoGrid instance and 2 Rackspace instances, and after a few minutes, there were 3 mod-cluster domains with 3, 1 and 2 servers respectively, and every server had ca 12 sessions on average !
This can be compared to a bookshop, which spins up additional servers in the cloud around the holidays to serve increased traffic, and where the servers form a cluster for redundancy (don't want to lose your shoppig cart !).
Enjoy the demo, and give us feedback on mod-cluster on the mailing list or forum.