lvm2/scripts/lvm2_pvscan_systemd_red_hat@.service.in

[Unit]
Description=LVM2 PV scan on device %i
Documentation=man:pvscan(8)
DefaultDependencies=no
BindsTo=dev-block-%i.device
After=lvm2-lvmetad.socket
Before=shutdown.target
Conflicts=shutdown.target

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=@sbindir@/pvscan --cache --activate ay /dev/block/%i
ExecStop=@sbindir@/pvscan --cache %i
udev+systemd: make pvscan --cache -aay run as systemd background job from udev The new lvm2-pvscan@.service is responsible for on-demand execution of "pvscan --cache --activate ay" which causes lvmetad to be updated and LVM activation done if the VG is complete. Also, use udev-systemd mechanism to instantiate the job as the lvm2-pvscan@$devnode.service on each newly appeared PV in the system. This prevents the background job to be killed (that would happen if it was directly forked from udev rule - this behaviour is seen in recent versions of udev with the help of systemd that can track detached processes - the detached process would still be in the same cgroup). To enable this official udev-systemd protocol for instantiating background jobs, use new --enable-udev-systemd-background-jobs configure switch (it's disabled by default). This option is highly recommended wherever systemd is used! 2013-10-18 13:07:21 +04:00			`[Unit]`
udev+systemd: refine lvm2-pvscan@.service to better track device existence When using ENV{SYSTEMD_WANTS}=lvm2-pvscan@... to instantiate a service for lvmetad scan when the new PV appears in the system, the service is started and executed. However, to track device removal, we need to bind it (the "BindsTo" systemd directive) to a certain .device systemd unit. In default systemd setup, the device is tracked by it's name and sysfs path (there's normally a sysfs path .device systemd unit for a device and then the device name .device unit as an alias for it). Neither of these two is useful for lvmetad update as we need to bind it to device's <major>:<minor> pair. The /dev/block/<major>:<minor> is the essential symlink under /dev that exists for each block device (created by default udev rules provided by udev directly). So let's use this as an alias for the device's .device unit as well by means of "ENV{SYSTEMD_ALIAS}" declaration within udev rules which systemd understands (this will create a new alias "dev-block-<major>:<minor>.device". Then we can easily bind the "dev-block-<major>:<minor>" device systemd unit with instantiated lvm2-pvscan@<major>:<minor>.service. So once the device is removed from the systemd, the lvm-pvscan@<major>:<minor>.service executes it's ExecStop action (which in turn notifies lvmetad about the device being gone). This completes the udev-systemd-lvmetad interaction then. 2013-10-22 16:03:53 +04:00			`Description=LVM2 PV scan on device %i`
udev+systemd: make pvscan --cache -aay run as systemd background job from udev The new lvm2-pvscan@.service is responsible for on-demand execution of "pvscan --cache --activate ay" which causes lvmetad to be updated and LVM activation done if the VG is complete. Also, use udev-systemd mechanism to instantiate the job as the lvm2-pvscan@$devnode.service on each newly appeared PV in the system. This prevents the background job to be killed (that would happen if it was directly forked from udev rule - this behaviour is seen in recent versions of udev with the help of systemd that can track detached processes - the detached process would still be in the same cgroup). To enable this official udev-systemd protocol for instantiating background jobs, use new --enable-udev-systemd-background-jobs configure switch (it's disabled by default). This option is highly recommended wherever systemd is used! 2013-10-18 13:07:21 +04:00			`Documentation=man:pvscan(8)`
			`DefaultDependencies=no`
udev+systemd: refine lvm2-pvscan@.service to better track device existence When using ENV{SYSTEMD_WANTS}=lvm2-pvscan@... to instantiate a service for lvmetad scan when the new PV appears in the system, the service is started and executed. However, to track device removal, we need to bind it (the "BindsTo" systemd directive) to a certain .device systemd unit. In default systemd setup, the device is tracked by it's name and sysfs path (there's normally a sysfs path .device systemd unit for a device and then the device name .device unit as an alias for it). Neither of these two is useful for lvmetad update as we need to bind it to device's <major>:<minor> pair. The /dev/block/<major>:<minor> is the essential symlink under /dev that exists for each block device (created by default udev rules provided by udev directly). So let's use this as an alias for the device's .device unit as well by means of "ENV{SYSTEMD_ALIAS}" declaration within udev rules which systemd understands (this will create a new alias "dev-block-<major>:<minor>.device". Then we can easily bind the "dev-block-<major>:<minor>" device systemd unit with instantiated lvm2-pvscan@<major>:<minor>.service. So once the device is removed from the systemd, the lvm-pvscan@<major>:<minor>.service executes it's ExecStop action (which in turn notifies lvmetad about the device being gone). This completes the udev-systemd-lvmetad interaction then. 2013-10-22 16:03:53 +04:00			`BindsTo=dev-block-%i.device`
			`After=lvm2-lvmetad.socket`
udev+systemd: make pvscan --cache -aay run as systemd background job from udev The new lvm2-pvscan@.service is responsible for on-demand execution of "pvscan --cache --activate ay" which causes lvmetad to be updated and LVM activation done if the VG is complete. Also, use udev-systemd mechanism to instantiate the job as the lvm2-pvscan@$devnode.service on each newly appeared PV in the system. This prevents the background job to be killed (that would happen if it was directly forked from udev rule - this behaviour is seen in recent versions of udev with the help of systemd that can track detached processes - the detached process would still be in the same cgroup). To enable this official udev-systemd protocol for instantiating background jobs, use new --enable-udev-systemd-background-jobs configure switch (it's disabled by default). This option is highly recommended wherever systemd is used! 2013-10-18 13:07:21 +04:00			`Before=shutdown.target`
			`Conflicts=shutdown.target`

			`[Service]`
udev+systemd: refine lvm2-pvscan@.service to better track device existence When using ENV{SYSTEMD_WANTS}=lvm2-pvscan@... to instantiate a service for lvmetad scan when the new PV appears in the system, the service is started and executed. However, to track device removal, we need to bind it (the "BindsTo" systemd directive) to a certain .device systemd unit. In default systemd setup, the device is tracked by it's name and sysfs path (there's normally a sysfs path .device systemd unit for a device and then the device name .device unit as an alias for it). Neither of these two is useful for lvmetad update as we need to bind it to device's <major>:<minor> pair. The /dev/block/<major>:<minor> is the essential symlink under /dev that exists for each block device (created by default udev rules provided by udev directly). So let's use this as an alias for the device's .device unit as well by means of "ENV{SYSTEMD_ALIAS}" declaration within udev rules which systemd understands (this will create a new alias "dev-block-<major>:<minor>.device". Then we can easily bind the "dev-block-<major>:<minor>" device systemd unit with instantiated lvm2-pvscan@<major>:<minor>.service. So once the device is removed from the systemd, the lvm-pvscan@<major>:<minor>.service executes it's ExecStop action (which in turn notifies lvmetad about the device being gone). This completes the udev-systemd-lvmetad interaction then. 2013-10-22 16:03:53 +04:00			`Type=oneshot`
			`RemainAfterExit=yes`
			`ExecStart=@sbindir@/pvscan --cache --activate ay /dev/block/%i`
cleanup: for commit 546db1c - properly clean lvm2-pvscan@.service on distclean - use @sbindir@ for sbin path in ExecStop 2013-10-23 11:48:33 +04:00			`ExecStop=@sbindir@/pvscan --cache %i`