Michal Schmidt <mschmidt <at> redhat.com> writes: > ... > > 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. > ... OK. Q: The sub-service-1.service and sub-service-2.service will be run as stand- alone processes (of whatever kind they are: daemon, master/slave, multithreaded), with no back references or dependecies of any kind (parent-child like, shared resources, etc) to main-service-1.service ? > > 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. > OK. Yes, I goofed here ... I meant some executable ... Let me repeat example 2: 2. main-service-2.service: [Unit] Description=Main service 2 After= ... ... [Service] Type=forking <---------------------- any other type too ? ExecStartPre= exec /etc/init.d/sub-service-1 ExecStartPre= exec /etc/init.d/sub-service-2 ExecStart= /usr/sbin/some-service ExecStartPost= ExecStartPost= ... Would the above be correct setup-wise ? Are there any restrictions on those Pre (and Post) commands ? > > 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. But this is what Steve, I believe, wants to do with nfs (to have a bunch of services started from the main one, as under current SysV init system, so his users are not confused by the startup of all these individual service files). > ... > > 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. Well, I wish I could (I am on F15) ... $ systemd-analyze plot <?xml version="1.0" encoding="UTF-8"?> <svg xmlns="http://www.w3.org/2000/svg"; xmlns:xlink="http://www.w3.org/1999/xlink"; width="1793pt" height="2290pt" viewBox="0 0 1793 2290" version="1.1"> <defs> <g> <symbol overflow="visible" id="glyph0-0"> <path style="stroke:none;" d="M 3.8125 -7.96875 C 3.207031 -7.96875 2.746094 -7 ... <use xlink:href="#glyph0-32" x="493.898438" y="2211.25"/> </g> </g> </svg> $ $ systemd-analyze plot |less Traceback (most recent call last): File "/usr/bin/systemd-analyze", line 221, in <module> surface.finish() IOError: [Errno 32] Broken pipe $ > This Lennart's blog post has an example: > http://0pointer.de/blog/projects/blame-game.html > > Michal Thanks. JB -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel
