Now with Whirr we have a service we can implement plus the run-urls, which are what the init-remote scripts used to be, but downloaded of a remote site as opposed to be compressed and piggybacked into the instance. Am I right here so far?
Yes, exactly right. In the future it would be nice to have the ability to push a local copy of the scripts out to the cluster (
WHIRR-99), but you don't need to worry about that in this issue.
Or is the HBase service supposed to start ZooKeeper if the user wishes to do so? Also, Tom, is there a way to daisy chain services?
It would be nice if HBase could use the ZK service to avoid duplication. Could the HBase service delegate to the ZK service to start and stop it? Patrick was talking about a more flexible model for starting services, so perhaps he's got some comments here too.
The other thing I would say is separate the installation script from the configuration script, so in the future we can do an optimization where we build pre-installed images. We have this separation in ZK, but not currently in Hadoop, although
WHIRR-87 will fix that.
Thanks for looking at this Lars!