[systemd-devel] Suggestion on StartLimitAction=

Michael Olbrich m.olbrich at pengutronix.de
Sun Feb 3 02:43:10 PST 2013

On Fri, Feb 01, 2013 at 03:22:49PM +0100, Allmeroth, Robert wrote:
> On embedded systems it is sometimes not very useful to call shutdown scripts 
> or reboot(2) in case of a watchdog failure / failed service (re)starting,
> e.g. FS/Flash corruption, FS driver failure, special HW init failure
> - Typically important file systems are read-only on embedded systems so it would
>   not harm the system to do a hard reset.
> - The processor on which systemd is running on is not necessarily the PowerController, a call
>   to reboot(2) would only stop/reboot that node. But other nodes like FPGA, ASIC, DSP also
>   need a reset.
> Does it make sense to you to have a StartLimitAction= where the systemd stops sending 
> heartbeats to the kernel? (e.g. StartLimitAction = StopKernelHeartbeat <optional reason>)
> In this case the watchdog on the PowerController is able to react very fast accordingly.
> Of course this will only work if the kernel watchdog module is already connected to the PowerController.
> If not - the only escape is the 'expect watchdog register timer' of the PowerController. 
> In general we would like to avoid running into the expect timer because we have no hint why the system 
> did not respond.

Have you looked at StartLimitAction=reboot-immediate? This should restart
your system immediately without stopping services etc.


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