Yeah. I understand the issues about the cluster evaporating and starting up without knowing the IP address. I just use it differently. I have an EC2 instance that I keep running all the time and that's my server.
But, you're right, there are some devilish details to work out if you want to materialize a cluster and have it magically start working without hand config. There's probably some scripting you could do... a script that you run on the machine that you start the EC2 instances from could ssh to each node and alter a configuration file (/etc/hosts comes to mind) after the cluster has started. vis-a-vis "no shared disk": you *could* run an NFS server on one of the EC2 instances if you wanted (I think-- I haven't actually tried). But, as I said, that's not an issue w/ Terracotta, since you can run Terracotta servers so that they synchronize across the network. The lack of a stable disk sounds like the biggest problem, since all of the other issues seem like they can be worked out with some clever scripting/configuration or something. What I've been doing is taking periodic snapshots and saving them to S3. That doesn't really solve the problem, but it's good enough for my purposes. I can tell this is going to bug me all day... --Orion hank williams wrote: > > On 9/7/07, Orion Letizi <[EMAIL PROTECTED]> wrote: >> >> >> Vis a vis IP addresses, the command 'ec2-describe-instances ' will show >> you >> the hostnames of the instances you have running. >> >> The terracotta server doesn't need to know the IP address of a connecting >> JVM. Each JVM that connects to the terracotta server needs to know the >> IP >> address of the server, but not the other way around. > > > But you dont know the IP address of the terracotta server until you launch > the EC2 instance. So you need a way to, on the fly, tell all the servers > what the master server's IP address is. I know it can be done, but the > devil > is in the details. The fact is I havent heard of anyone who *has* done it, > or who has published code or an AMI. > > When I've set up >> terracotta clusters on EC2, I assume that the server is long lived. I >> haven't really thought about how to make an entire cluster just start up >> without some configuration, but I'm sure there's some clever way to do >> it. >> > > > This is critical since in a real environment you *cant* assume that the > server is long lived - particularly on EC2 where you loose everything - > your > IP address, machine name, and data. > > Vis a vis what happens if the terracotta server goes down: you can run > them >> in pairs (or, really, any number) so that if the primary server goes >> down, >> a >> secondary will automatically take over. The servers can be synchronized >> using a shared disk (e.g., NFS) or over a network. > > > There is no shared disk in EC2. There is S3, but it is not NFS and not > random access. It really is only useful right now for backup, not as a > shared disk between two servers. > > Running tomcat clustered with terracotta on EC2 is really no different > than >> running tomcat clustered on any other multi-node environment. > > > > I would beg to differ, because not having stable IP and Hard disk is a big > difference. > > What >> information, specifically, are you looking for? > > > What I am trying to figure out is how to use tomcat on EC2 in a safely > deployable way. Terracotta seems like a good way, though it appears a real > deployable scenario isnt quite worked out. By your question it sounds like > you may not realize that this is the *** #1 *** issue in the EC2 > community. > There are no good solutions - at least that have been published - for > cleanly dealing with no static IP address, no persistent disk, and the > related issues of load balancing, scaling and restarting. > > For you guys (terracotta), getting a clean simple setup for running > terracotta + tomcat on EC2 would be a *huge* win for establishing it in > the > EC2 community since it is such a critical issue. > > Regards, > Hank > > _______________________________________________ > Red5 mailing list > [email protected] > http://osflash.org/mailman/listinfo/red5_osflash.org > > -- View this message in context: http://www.nabble.com/terracotta---ec2-tf4395743.html#a12559070 Sent from the Red5 - English mailing list archive at Nabble.com. _______________________________________________ Red5 mailing list [email protected] http://osflash.org/mailman/listinfo/red5_osflash.org
