Been experimenting with the pack module and it works really well. The only problem is that to get sites to use the "pack" server, they have to be migrated to a platform on the "pack" server. Migrating a couple of hundred sites to add/remove a node to/from a cluster is a bit clunky.
Because of this, I'd like to try and manage the cluster manually so we can add/remove new members to the cluster quickly. So Aegir isn't even aware of the other web servers, they're just added to our load balancers when needed.
In a non-Aegir environment this wouldn't be a problem... - DocumentRoots mounted over NFS - When changes are made to the vhosts we just rsync the vhost configurations to cluster members and trigger a graceful restart In non-Aegir environments I handle all of this through Puppet, including the addition/removal of nodes in the cluster.
There are two blockers with Aegir that prevent us from doing this manually:
1) Is there a hook in Aegir that lets us trigger a shell script on the master when a verify/migrate/clone etc task is completed? This would handle the config rsync and Apache graceful.
2) The MySQL user accounts created by Aegir are bound to the IP address of the web server. Is it possible to set this to '%' instead, so that the site-specific username/password can be used from any host?