Re: [systemd-devel] Question on Before=
On 2/2/19 3:44 PM, Reindl Harald wrote: > > > Am 02.02.19 um 21:05 schrieb Steve Dickson: >> On 2/2/19 2:52 PM, Reindl Harald wrote: >>> Am 02.02.19 um 20:42 schrieb Steve Dickson: Hello, In a.service I have [Unit] Before=b.service [Install] RequiredBy=b.service when I systemd start b.service (which happens to fail) but... a.service is not being run. So I guess my question is what do I have to do to ensure a.service is *always* run before b.service? >>> [Install] RequiredBy=b.service >>> >>> why? >>> >>> [Unit] >>> Before/After/Require >>> >>> [Install] >>> WantedBy=multi-user.target >> Because a.service only needs to run when b.service is started. > > this is a cirrcualr dependency! > > you say "start a before b" and at the same time "start a only when b is > started" > > hwo do you imagine that to work? > That a would start before b because of the Before= in a. There was an issue as how I was enabling a... thanks for the help! steved. ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Question on Before=
On 2/2/19 4:03 PM, Tomasz Torcz wrote: > On Sat, Feb 02, 2019 at 03:03:22PM -0500, Steve Dickson wrote: >> >> >> On 2/2/19 2:48 PM, Tomasz Torcz wrote: >>> On Sat, Feb 02, 2019 at 02:42:15PM -0500, Steve Dickson wrote: Hello, In a.service I have [Unit] Before=b.service [Install] RequiredBy=b.service when I systemd start b.service (which happens to fail) but... a.service is not being run. So I guess my question is what do I have to do to ensure a.service is *always* run before b.service? >>> >>> Have you enabled a.service? >>> >> No... I did not think I had to... I figured >> when b.service was started, a.service would be >> run regardless of being enabled or disabled. >> >> Is that not the case? > > Not really. It would work, if you had in b.service line like > Requires=a.service (*). > But apparently you do not want to modify b.service, so you > put RequiredBy= in a.service's [Install] section. Directives > in [Install] section requires "systemctl enable" to have symlinks > created and to have effect. After enable, it will work identical to (*). > > Nb. most services have RequireBy=multi-user.target (or WantedBy=). For > such services, enabling mean they will start at boot (beacuse > multi-user.target is part of boot process). But there is not > requirement for services to be Wanted/Required by not boot-related > services and target. > Thus, you often find in tutorials assertion that > "systemctl enable" equals "start during boot". This is not true. It turns out I had a bug in my spec file logic which should have enabled the service... Thanks for the help! steved. > > ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Question on Before=
On 2/2/19 4:07 PM, Uoti Urpala wrote: > On Sat, 2019-02-02 at 15:03 -0500, Steve Dickson wrote: >>> Have you enabled a.service? >>> >> No... I did not think I had to... I figured >> when b.service was started, a.service would be >> run regardless of being enabled or disabled. >> >> Is that not the case? > > So you just have the file for a.service lying somewhere on disk, but > haven't enabled it and no other unit references it? That is true... > That won't do anything - systemd does not read through all files on disk to > see if > there'd be something inside the file which declares that it should > actually be started. Units need to have something else referencing them > for systemd to "see" them at all. "enable" does this by creating a link > from the units/targets referenced in the [Install] section to the file > in question (by creating a symlink in > /etc/systemd/system/multi-user.target.wants/ for example). Basically enabling the service... fair enough... steved. ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Question on Before=
On Sat, Feb 02, 2019 at 03:03:22PM -0500, Steve Dickson wrote: > > > On 2/2/19 2:48 PM, Tomasz Torcz wrote: > > On Sat, Feb 02, 2019 at 02:42:15PM -0500, Steve Dickson wrote: > >> Hello, > >> > >> In a.service I have > >> > >> [Unit] > >> Before=b.service > >> > >> [Install] > >> RequiredBy=b.service > >> > >> when I systemd start b.service (which happens to fail) > >> but... a.service is not being run. > >> > >> So I guess my question is what do I have to do > >> to ensure a.service is *always* run before b.service? > > > > Have you enabled a.service? > > > No... I did not think I had to... I figured > when b.service was started, a.service would be > run regardless of being enabled or disabled. > > Is that not the case? Not really. It would work, if you had in b.service line like Requires=a.service (*). But apparently you do not want to modify b.service, so you put RequiredBy= in a.service's [Install] section. Directives in [Install] section requires "systemctl enable" to have symlinks created and to have effect. After enable, it will work identical to (*). Nb. most services have RequireBy=multi-user.target (or WantedBy=). For such services, enabling mean they will start at boot (beacuse multi-user.target is part of boot process). But there is not requirement for services to be Wanted/Required by not boot-related services and target. Thus, you often find in tutorials assertion that "systemctl enable" equals "start during boot". This is not true. -- Tomasz Torcz"Funeral in the morning, IDE hacking xmpp: zdzich...@chrome.plin the afternoon and evening." - Alan Cox ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Question on Before=
On Sat, 2019-02-02 at 15:03 -0500, Steve Dickson wrote: > > Have you enabled a.service? > > > No... I did not think I had to... I figured > when b.service was started, a.service would be > run regardless of being enabled or disabled. > > Is that not the case? So you just have the file for a.service lying somewhere on disk, but haven't enabled it and no other unit references it? That won't do anything - systemd does not read through all files on disk to see if there'd be something inside the file which declares that it should actually be started. Units need to have something else referencing them for systemd to "see" them at all. "enable" does this by creating a link from the units/targets referenced in the [Install] section to the file in question (by creating a symlink in /etc/systemd/system/multi-user.target.wants/ for example). ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Question on Before=
Am 02.02.19 um 21:05 schrieb Steve Dickson: > On 2/2/19 2:52 PM, Reindl Harald wrote: >> Am 02.02.19 um 20:42 schrieb Steve Dickson: >>> Hello, >>> >>> In a.service I have >>> >>> [Unit] >>> Before=b.service >>> >>> [Install] >>> RequiredBy=b.service >>> >>> when I systemd start b.service (which happens to fail) >>> but... a.service is not being run. >>> >>> So I guess my question is what do I have to do >>> to ensure a.service is *always* run before b.service? >> >>> [Install] >>> RequiredBy=b.service >> >> why? >> >> [Unit] >> Before/After/Require >> >> [Install] >> WantedBy=multi-user.target > Because a.service only needs to run when b.service is started. this is a cirrcualr dependency! you say "start a before b" and at the same time "start a only when b is started" hwo do you imagine that to work? ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Question on Before=
Am 02.02.19 um 21:03 schrieb Steve Dickson: > On 2/2/19 2:48 PM, Tomasz Torcz wrote: >> On Sat, Feb 02, 2019 at 02:42:15PM -0500, Steve Dickson wrote: >>> Hello, >>> >>> In a.service I have >>> >>> [Unit] >>> Before=b.service >>> >>> [Install] >>> RequiredBy=b.service >>> >>> when I systemd start b.service (which happens to fail) >>> but... a.service is not being run. >>> >>> So I guess my question is what do I have to do >>> to ensure a.service is *always* run before b.service? >> >> Have you enabled a.service? >> > No... I did not think I had to... I figured > when b.service was started, a.service would be > run regardless of being enabled or disabled. > > Is that not the case? that's not how it works ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Question on Before=
On 2/2/19 2:52 PM, Reindl Harald wrote: > > > Am 02.02.19 um 20:42 schrieb Steve Dickson: >> Hello, >> >> In a.service I have >> >> [Unit] >> Before=b.service >> >> [Install] >> RequiredBy=b.service >> >> when I systemd start b.service (which happens to fail) >> but... a.service is not being run. >> >> So I guess my question is what do I have to do >> to ensure a.service is *always* run before b.service? > >> [Install] >> RequiredBy=b.service > > why? > > [Unit] > Before/After/Require > > [Install] > WantedBy=multi-user.target Because a.service only needs to run when b.service is started. steved. > ___ > systemd-devel mailing list > systemd-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/systemd-devel > ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Question on Before=
On 2/2/19 2:48 PM, Tomasz Torcz wrote: > On Sat, Feb 02, 2019 at 02:42:15PM -0500, Steve Dickson wrote: >> Hello, >> >> In a.service I have >> >> [Unit] >> Before=b.service >> >> [Install] >> RequiredBy=b.service >> >> when I systemd start b.service (which happens to fail) >> but... a.service is not being run. >> >> So I guess my question is what do I have to do >> to ensure a.service is *always* run before b.service? > > Have you enabled a.service? > No... I did not think I had to... I figured when b.service was started, a.service would be run regardless of being enabled or disabled. Is that not the case? steved. ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Question on Before=
On Sat, Feb 02, 2019 at 02:42:15PM -0500, Steve Dickson wrote: > Hello, > > In a.service I have > > [Unit] > Before=b.service > > [Install] > RequiredBy=b.service > > when I systemd start b.service (which happens to fail) > but... a.service is not being run. > > So I guess my question is what do I have to do > to ensure a.service is *always* run before b.service? Have you enabled a.service? -- Tomasz Torcz"Funeral in the morning, IDE hacking xmpp: zdzich...@chrome.plin the afternoon and evening." - Alan Cox ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Question on Before=
Am 02.02.19 um 20:42 schrieb Steve Dickson: > Hello, > > In a.service I have > > [Unit] > Before=b.service > > [Install] > RequiredBy=b.service > > when I systemd start b.service (which happens to fail) > but... a.service is not being run. > > So I guess my question is what do I have to do > to ensure a.service is *always* run before b.service? > [Install] > RequiredBy=b.service why? [Unit] Before/After/Require [Install] WantedBy=multi-user.target ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
[systemd-devel] Question on Before=
Hello, In a.service I have [Unit] Before=b.service [Install] RequiredBy=b.service when I systemd start b.service (which happens to fail) but... a.service is not being run. So I guess my question is what do I have to do to ensure a.service is *always* run before b.service? tia, steved. ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] How to schedule a resource consuming service
02.02.2019 16:50, Fabrice Salvaire пишет: > Dear all, > > In Fedora mlocate (updatedb) service is setup like this > > -- > >> cat /usr/lib/systemd/system/mlocate-updatedb.service > [Unit] > Description=Update a database for mlocate > > [Service] > ExecStart=/usr/libexec/mlocate-run-updatedb > Nice=19 > IOSchedulingClass=2 > IOSchedulingPriority=7 > > PrivateTmp=true > PrivateDevices=true > PrivateNetwork=true > ProtectSystem=true > > -- > >> cat /usr/lib/systemd/system/mlocate-updatedb.timer > [Unit] > Description=Updates mlocate database every day > > [Timer] > OnCalendar=daily > AccuracySec=24h > Persistent=true > > [Install] > WantedBy=timers.target > -- > > Unfortunately it saturates the IO after the boot when the machine was > not running at midnight (not sure ???), see > https://bugzilla.redhat.com/show_bug.cgi?id=1282232 > Similar problem was discussed for openSUSE as well (similar in the sense that Persistent=true results in serious impact during boot). Some way to delay Persistent=true would be nice indeed. > This is painful when we want to use the machine asap, for a quite full > 500 GB disk, it hangs during several minutes. I encountered an unusable > machine during more than 10 min due to mlocate and/or gnome indexer > saturating IO and package cache update saturating a low ADSL connexion. > > I noticed IOSchedulingClass=2 could be set to "idle", maybe it would > improve. > > I also read > https://www.freedesktop.org/software/systemd/man/systemd.timer.html but > I don't understand if there is a way to prevent to run the service > during 1h after boot. > > Well a way to run theses services during idle time. > Define "idle time" ... ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
[systemd-devel] How to schedule a resource consuming service
Dear all, In Fedora mlocate (updatedb) service is setup like this -- > cat /usr/lib/systemd/system/mlocate-updatedb.service [Unit] Description=Update a database for mlocate [Service] ExecStart=/usr/libexec/mlocate-run-updatedb Nice=19 IOSchedulingClass=2 IOSchedulingPriority=7 PrivateTmp=true PrivateDevices=true PrivateNetwork=true ProtectSystem=true -- > cat /usr/lib/systemd/system/mlocate-updatedb.timer [Unit] Description=Updates mlocate database every day [Timer] OnCalendar=daily AccuracySec=24h Persistent=true [Install] WantedBy=timers.target -- Unfortunately it saturates the IO after the boot when the machine was not running at midnight (not sure ???), see https://bugzilla.redhat.com/show_bug.cgi?id=1282232 This is painful when we want to use the machine asap, for a quite full 500 GB disk, it hangs during several minutes. I encountered an unusable machine during more than 10 min due to mlocate and/or gnome indexer saturating IO and package cache update saturating a low ADSL connexion. I noticed IOSchedulingClass=2 could be set to "idle", maybe it would improve. I also read https://www.freedesktop.org/software/systemd/man/systemd.timer.html but I don't understand if there is a way to prevent to run the service during 1h after boot. Well a way to run theses services during idle time. Cheers, Fabrice ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
