Arvados

Basic idea: we should not ship a separate package for the subcommands of arvados-server (controller, crunch-run, crunchstat, dispatch-*, keep-web, keepproxy, keepstore, ws). Instead the arvados-server package should grow to:

• include all related service unit definitions
• include symlinks for the subcommands to point to /usr/bin/arvados-server
• declare it Replaces all those subcommand packages

The main reason we have separate packages now is to manage the services separately. But we have never done service management in our package scripts properly, and it's a task we would rather leave to installer like Salt/Ansible. A single arvados-server package would be faster to build, faster to deploy, and save disk space. The package postinst script could also become a place to centrally manage /etc/arvados, since we can expect every server involved in running a cluster to have arvados-server installed (note even arvados-api-server depends on arvados-server, even if it doesn't end up running any arvados-server services).

Per Peter, the systemd service definitions should be updated to run arvados-server subcommands rather than relying on the symlinks.