'Twas brillig, and Lennart Poettering at 25/07/13 20:59 did gyre and gimble: > On Thu, 25.07.13 21:21, Tomasz Torcz ([email protected]) wrote: > >> On Thu, Jul 25, 2013 at 06:51:21PM +0200, Lennart Poettering wrote: >>> On Fri, 19.07.13 21:05, Pablo Nehab Hess ([email protected]) wrote: >>> >>>> Hi all, >>>> >>>> I was wondering how much systemd could add to current high >>>> availability cluster setups. >>>> >>>> Today systemd is used on HA clusters as just an init replacement. >>>> However, there are systemd features that might come in handy and >>>> improve the overall performance and even reliability of such clusters: >>>> >>>> * watchdog functionality as in >>>> <http://0pointer.de/blog/projects/watchdog.html> is the most evident >>>> feature; >>>> * tcp-based dbus communication could be used to exchange information >>>> between cluster members; >>>> >>>> Also, I believe systemd functionality could be extended so it would >>>> take into consideration other nodes' systemd instances in order to >>>> make sure each service is always alive somewhere -- call it "floating >>>> units" if you will. :-) >>>> >>>> Does this idea even make sense? Is it too "one systemd to rule them all"? >>> >>> Well, I don't really know what exactly HA clusters would need. However, >>> note that we actually do try to draw the line somewhere where systemd >>> ends... I have the suspicion the HA cluster stuff something which could >>> make great use of systemd's comprehensive bus interfaces, but I am not >>> convinced such a project should sit in systemd itself. >> >> The RH Cluster suite cares about running services, and restarting services >> when they fail. Just like systemd. Main difference is that you can select >> on which host to run this service. > > Well we have "-H" already. What more do you need? > >> It could be implemented in some daemon >> synchronising state between remote systemd's. >> Every time I use ”clustat” I feel like I'm should be looking at >> ”systemctl status” listing. When I enable services using ”clusvcadm -e foo” >> I feel like it should be ”systemctl enable foo”. There's a quite big >> overlap between cluster suite and systemctl. > > So these tools will walk the cluster and get the status of the > respective service on all machines?
Not sure if it's a walk as such, but the outcome is exactly that yes. I've not used clustat and such for a while tho', so am a bit rusty. Col -- Colin Guthrie gmane(at)colin.guthr.ie http://colin.guthr.ie/ Day Job: Tribalogic Limited http://www.tribalogic.net/ Open Source: Mageia Contributor http://www.mageia.org/ PulseAudio Hacker http://www.pulseaudio.org/ Trac Hacker http://trac.edgewall.org/ _______________________________________________ systemd-devel mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/systemd-devel
