[OE-core] [PATCH] systemd.bbclass: don't block on service restart

[Andreas Oberritter]

On 25.11.2016 05:17, Mark Asselstine wrote:
> The current class works fine when a recipe uses SYSTEMD_AUTO_ENABLE
> 'enable' and has no on device pkg_postinst(), ie when the postinst is
> run as part of rootfs creation.  However, when there is a component of
> pkg_postinst() that is run on device the 'systemctl restart' is run as
> part of the run_postinsts.service at boot. This results in the boot
> spinning indefinitely with:
> 
> [ *** ] A start job is running for Run pending postinsts (7s / no limit)
> 
> The issue could potentially be that the packages service has an
> 'After' clause which comes later in the boot, beyond
> run_postinsts.service, creating a chicken before the egg
> scenario. Even service files without an 'After' clause cause this
> situation however. Despite this not being the cause of the issue this
> fix will prevent this scenario from happenning.
> 
> Using strace we are able to find that during boot, when
> run_postinsts.service is running attempting to start or restart any
> service will result in the call get stuck on poll(). Since the
> run_postinsts.service does not monitor the outcome of the call to
> restart we can work around this by using '--no-block'.
> 
> Signed-off-by: Mark Asselstine <mark.asselstine at windriver.com>

I was going to submit the exact same patch soon. It also helps to
complete system updates if a service fails to restart properly.

Acked-by: Andreas Oberritter <obi at opendreambox.org>

> ---
>  meta/classes/systemd.bbclass | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/meta/classes/systemd.bbclass b/meta/classes/systemd.bbclass
> index 7e51ed6..99a08a0 100644
> --- a/meta/classes/systemd.bbclass
> +++ b/meta/classes/systemd.bbclass
> @@ -36,7 +36,7 @@ if type systemctl >/dev/null 2>/dev/null; then
>  	systemctl $OPTS ${SYSTEMD_AUTO_ENABLE} ${SYSTEMD_SERVICE}
>  
>  	if [ -z "$D" -a "${SYSTEMD_AUTO_ENABLE}" = "enable" ]; then
> -		systemctl restart ${SYSTEMD_SERVICE}
> +		systemctl --no-block restart ${SYSTEMD_SERVICE}
>  	fi
>  fi
>  }
>