On Mon, 11 Jul 2011 08:44:16 +0000 (UTC) JB wrote: > Let me take a shot at 2 examples of service files below. > Are they correct setup-wise ? > Will both examples be executed sequentially only ? > > 1. > > main-service-1.service: > [Unit] > Description=Main service 1 > Requires= ... sub-service-1.service sub-service-2.service > After= ... sub-service-1.service sub-service-2.service > ... > [Service] > Type=forking <---------------------- any other type too ? > ExecStartPre= > ExecStartPre= > ExecStart= > ExecStart= /usr/sbin/some-service Nitpick: You can have only one ExecStart= in a forking unit. Only oneshot units can have more. > ExecStartPost= > ExecStartPost= > ... > > sub-service-1.service: > [Unit] > Description=Sub service 1 > ... > [Service] > ... > > sub-service-2.service: > [Unit] > Description=Sub service 2 > ... > [Service] > ... First, sub-service-1.service and sub-service-2.service will be started in parallel. When they're running, main-service-1.service will be started by processing its ExecStart* commands sequentially. > 2. > > main-service-2.service: > [Unit] > Description=Main service 2 > After= ... > ... > [Service] > Type=forking <---------------------- any other type too ? > ExecStartPre= sub-service-1.service > ExecStartPre= sub-service-2.service This is incorrect. ExecStartPre= expects a command to run, not a unit name. > What if sysadmin wants to execute them in parallel because she knows > they can be executed this way (no conflict and no races) ? > How, if by definition, systemd executes them sequentially only ? > Can they be grouped and execution-parallelized in the whole service > file, or at least in subgroups Pre-, regular, and Post- ? Parallelism in systemd happens between multiple units, but never between ExecStart* commands of one unit. Requesting parallelism within one unit seems like over-engineering to me. You can always split your unit to smaller ones if you want parallelism. > Can you give us a working example of a services setup (or something > else) in systemd where execution-parallelism would be present or at > least theoretically exploitable ? Take a look at 'systemd-analyze plot' where you can clearly see services starting in parallel. This Lennart's blog post has an example: http://0pointer.de/blog/projects/blame-game.html Michal -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel
