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mLine 1:
Line 1: − + − Basically we use SysVinit, with initscripts built to handle a specific run level rc7.d. On top of that we use Runit to handle services indexed in /services / and /var/services. + − + − + + Line 25:
Line 26: − + − + + + + + − We have added a first systemd unit for bootstrap console and make it a drop in replacement of Sysvinit to boot all processes linked in /etc/rc.d/rc7.d/.+ − From there we could keep this way, or try to move as many process as we can to systemd. This way works, but is even more complex than it was on previous SME version. Plus we can not guarantee without further scripts that one will not be able to do a ''systemctl start httpd''.+ − Line 167:
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Line 343: − + − this is intended to make an open discussion about possibilities, in order to choose the best SME approach to systemd.+ − Issue to solve :+ − + − + − + − + − + − + + Line 383:
Line 390: − + − there have been suggestions about using a generator, it is not clear how and why it would help. This approach would be more complex. and according to the doc<ref>https://www.freedesktop.org/software/systemd/man/systemd.generator.html#</ref>: + − + − + − + + + + + + + + + + + + + + + + + + + + + + + + + − + − Thinking of the example of a service unit provided by upstream vendor. Should we simply create a template and expand it over the unit.service in /lib/systemd/system/ or offer a different way to override upstream vendor settings ? Further more should we template our file to point to /lib/ or to /etc/. In other words, should we fight with admin space trying to overwrite changes in its dedicated space or should we fight with upstream vendors and overwrite their files or find a way to override them. − hence the questions+ − * where: /etc or /lib/ − * How : template or not − * How: overwrite or selective overriding − ===== unit files created in /etc/systemd/system/ or in /lib/systemd/system/ =====+ − as a vendor we should work in /lib/systemd/system/, but as an admin helper we might want to play in /etc/systemd/system/ and rather offer a way to admin to use our template-custom or config db. − ==== template or not ====+ − the first easy way to think to override ones service could be to simply template the file /lib/systemd/system/servicename.service and expand it every time a reconfiguration or a boot occurs. − Going futher we could ensure the stability of the system by making this in /etc/systemd/system/servicename.service+ − ===== unitname.d/file.conf versus overwrite uniname.service =====+ − − + − The advantage of the first method is that one easily overrides the complete unit, the vendor unit is not parsed at all anymore. It has the disadvantage that improvements to the unit file by the vendor are not automatically incorporated on updates.+ − The advantage of the second method is that one only overrides the settings one specifically wants, where updates to the unit by the vendor automatically apply. This has the disadvantage that some future updates by the vendor might be incompatible with the local changes. <ref>https://www.freedesktop.org/software/systemd/man/systemd.unit.html</ref>+ − ==== uninstalling /masking unwanted/conflicting services: example of firewalld. ====+ − we can plan to uninstall firewalld for example, but some packages will reinstall as a requirement. It might even be started, which could conflict with masq. − === Systemd current implementation ===+ − Previously we had sysvinit services and supervised services under Deamontool and Runit. − We are currently moving all sysvinit handled service to systemd. + − For services supervised with Runit, we either move them to systemd with their own unit if one is provided, or we create one which will keep the service runing under Runit+ − The idea is to stop to have the Bootstrap Console to start services.+ + − + + + + + + + − + − + − + − + − This is important that this file is called 49-koozali.preset and not 50-Koozali.preset, so it does not hide 50-Koozali.preset content, but take precedence on it. Hence, anything not declared in 49-koozali.preset will take the state of what declare the 50 one.+ − + Line 447:
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Line 526: − + − + − * sigusr1 − * sigusr2 − * sigterm − * sighup − + − + − + − + − + − + − + − + + + + + + + − ==== Service migration ====+ − * We will have all our service unit file in /usr/lib/systemd/system/ − * They should all be wanted by sme-server.target in the [Install] − * As long as possible we will avoid to template .service files and/or their modification in /usr/lib/systemd/system/servicename.service.d/50koozali.conf − ===== Previous pure Syvinit service, with a provided systemd unit =====+ − Either we are lucky and can simply use the one provided as a replacement, either we add a service.d/50koozali.conf for the service and alter in a way we need.+ + − + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + Line 567:
Line 673: − + − Either we are lucky and can simply use the one provided as a replacement, either we add a service.d/50koozali.conf for the service and alter in a way we need.+ + + − AS a last resort we could hide the whole file using the service.d/50koozali.conf and simply call runit, see next one.+ − + Line 592:
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system/preset to system-preset
=== Previous version boot process and service control ===
===Versions previous to 10: boot process and service control===
SysVinit is used, with initscripts built to handle a specific run level rc7.d. Over that we use Runit to handle services indexed in /services / and /var/services.
A cli wrapper for the command service /sbin/e-smith/service has been created so that only initscripts which exist in run-level 7 can be run. This ensures that the supervised service is run, if one exists, and protects against running "service httpd restart". The wrapper will also choose between a sv command for runit processes or regular call to /etc/rc.d/init.d/ scripts.
A cli wrapper for the command service /sbin/e-smith/service has been created so that only initscripts which exist in run-level 7 can be run. This ensures that the supervised service is run, if one exists, and protects against running e.g. "service httpd restart" directly. The wrapper will also choose between an sv command for runit processes or a regular call to /etc/rc.d/init.d/ scripts.
* /sbin/e-smith/service
*/sbin/e-smith/service
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
#! /bin/sh
#! /bin/sh
</syntaxhighlight>
</syntaxhighlight>
=== Current SME10 alpha boot process and service control ===
===Version 10 on: boot process and service control===
Systemd has been designed as the way to handle services upstream. Systemd will override all /etc/rc.d/init.d/ scripts and call to /usr/sbin/service.
====Current SME10 alpha boot process and service control====
Systemd is the new Linux standard to handle services and service monitoring and is enforced upstream. Systemd will supersede all /etc/rc.d/init.d/ scripts and calls to /usr/sbin/service.
We have added a first systemd unit to bootstrap the console and made it a drop in replacement of Sysvinit to boot all processes linked in /etc/rc.d/rc7.d/.
From there we could continue in this way, or try to move as many processes as we can to systemd. That works, but is even more complex than it was in the previous SME versions. Additionally we can not guarantee—without further scripts—that an issued ''systemctl start httpd'' would be blocked.
*new startup with console see /usr/share/perl5/vendor_perl/esmith/console/startup.pm
* new startup with console see /usr/share/perl5/vendor_perl/esmith/console/startup.pm
<syntaxhighlight lang="perl">
<syntaxhighlight lang="perl">
package esmith::console::startup;
package esmith::console::startup;
</syntaxhighlight>
</syntaxhighlight>
* a new /sbin/e-smith/service
*a new /sbin/e-smith/service
<syntaxhighlight lang="bash" line="1">
<syntaxhighlight lang="bash" line="1">
#! /bin/sh
#! /bin/sh
</syntaxhighlight>
</syntaxhighlight>
* And the current controlService perl function from /usr/share/perl5/vendor_perl/esmith/util.pm
*And the current controlService perl function from /usr/share/perl5/vendor_perl/esmith/util.pm
<syntaxhighlight lang="perl" line="1">
<syntaxhighlight lang="perl" line="1">
=pod
=pod
</syntaxhighlight>
</syntaxhighlight>
=== Systemd Integration possibilities ===
===Systemd Integration: Options and possibilities===
This section is intended to open up a discussion concerning options and possibilities, in order to facilitate choosing the optimal SME approach to systemd.
Issues to solve :
* SME vs upstream
* make unit files aware of service status in e-smith db configuration
*SME vs. upstream
* have our services boot in the right sequence
*make unit files aware of service status in e-smith db configuration
* journald vs rsyslogd
*have our services boot in the right sequence
* plain file log vs special file format
*journald vs rsyslogd
* enabling /disabling /masking services
*plain file log vs special file format
*enabling /disabling /masking services
'''Table 1. Load path when running in system mode (<code>--system</code>).''' <ref>https://www.freedesktop.org/software/systemd/man/systemd.unit.html</ref>
'''Table 1. Load path when running in system mode (<code>--system</code>).''' <ref>https://www.freedesktop.org/software/systemd/man/systemd.unit.html</ref>
|}
|}
==== generators ====
====Generators====
There have been suggestions about using a generator, it is not clear how and why it would help. This approach would be more complex. and according to the doc<ref>https://www.freedesktop.org/software/systemd/man/systemd.generator.html#</ref>:
* Units written by generators are removed when the configuration is reloaded. That means the lifetime of the generated units is closely bound to the reload cycles of '''systemd''' itself.
* Generators should only be used to generate unit files and symlinks to them, not any other kind of configuration. Due to the lifecycle logic mentioned above, generators are not a good fit to generate dynamic configuration for other services. If you need to generate dynamic configuration for other services, do so in normal services you order before the service in question.
*Units written by generators are removed when the configuration is reloaded. That means the lifetime of the generated units is closely bound to the reload cycles of '''systemd''' itself.
systemctl daemon-reload has be run after each modification of a unit. Hence generated files by generators will be erase and generators rerun. <ref>https://www.freedesktop.org/software/systemd/man/systemctl.html#daemon-reload</ref>
*Generators should only be used to generate unit files and symlinks to them, not any other kind of configuration. Due to the lifecycle logic mentioned above, generators are not a good fit to generate dynamic configuration for other services. If you need to generate dynamic configuration for other services, do so in normal services you order before the service in question.
systemctl daemon-reload has be run after each modification of a unit. Hence generated files by generators will be erased and generators rerun. <ref>https://www.freedesktop.org/software/systemd/man/systemctl.html#daemon-reload</ref>
====Overriding the upstream vendor preset : templated unit files, or not? And where?====
The reference is the example of a service unit provided by the upstream vendor.
*Should we simply create a template and expand it over the unit.service in /lib/systemd/system/
*Or offer a different way to override upstream vendor settings?
Furthermore should we template our file to point to /lib/ or to /etc/?
In other words, should we fight with admin space trying to overwrite changes in its dedicated space, or should we fight with upstream vendors and overwrite their files or find a way to override them?
Thus the questions arise:
*Where: /etc or /lib/
*What: use a template or not
*How: overwrite, or selective overriding
Looking at the options:
====Create unit files in /etc/systemd/system/ or in /lib/systemd/system/?====
:As a vendor we should work in /lib/systemd/system/, but as an admin helper we might want to play in /etc/systemd/system/ and rather offer a way for admin to use our template-custom or config db.
==== Overide upstream vendor preset : templated unit files or not ? where ? ====
====Template or not?====
:The simplest way to override a service could be to simply template the file /lib/systemd/system/servicename.service and expand it every time a reconfiguration or a boot occurs.
:Going further, we could ensure the stability of the system by setting this in
:/etc/systemd/system/servicename.service
=====unitname.d/file.conf versus overwrite uniname.service=====
:From reading and inspection of a few systems, a dot d folder could be created both in etc and lib.
dot d folder can be created both int etc and lib from readings and inspection in a few systems.
There are two methods of overriding vendor settings in unit files: copying the unit file from <code>/usr/lib/systemd/system</code> to <code>/etc/systemd/system</code> and modifying the chosen settings. Alternatively, one can create a directory named <code>''<code>unit</code>''.d/</code> within <code>/etc/systemd/system</code> and place a drop-in file <code>''<code>name</code>''.conf</code> there that only changes the specific settings one is interested in. Note that multiple such drop-in files are read if present, processed in lexicographic order of their filename.
:There are two methods of overriding vendor settings in unit files:
::First, copying the unit file from <code>/usr/lib/systemd/system</code> to <code>/etc/systemd/system</code> and modifying the chosen settings.
::Second, one can create a directory named <code>''<code>unit</code>''.d/</code> within <code>/etc/systemd/system</code> and place a drop-in file there <code>''<code>name</code>''.conf</code> that only changes the specific settings one is interested in. Note that multiple such drop-in files are read if present, processed in lexicographic order of their filename.
:The advantage of the first method is that one easily overrides the complete unit, the vendor unit is not parsed at all anymore. It has the disadvantage that improvements to the unit file by the vendor are not automatically incorporated on updates.
:The advantage of the second method is that one only overrides the settings one specifically wants, where updates to the unit by the vendor automatically apply. This has the disadvantage that some future updates by the vendor might be incompatible with the local changes.<ref>https://www.freedesktop.org/software/systemd/man/systemd.unit.html</ref>
=====Uninstalling/masking unwanted/conflicting services: firewalld example=====
:We can plan to uninstall firewalld for example, but some packages will reinstall as a requirement. It might even be started, which could conflict with masq.
===Systemd current implementation===
Previously we had sysvinit services and supervised services under Daemontool and Runit.
==== default target: sme-server.target ====
We are currently moving all sysvinit handled service to systemd.
For services supervised with Runit, we either move them to systemd with their own unit if one is provided, or we create one which will keep the service running under Runit
The idea is to stop to have the Bootstrap Console start services.
====default target: sme-server.target====
We use our own target.
We use our own target.
==== system-preset ====
====system-preset====
The use of system preset is the base of our way to handle the systemd services under Koozali SME Server.
The use of system presets is the basis of our method of handling the systemd services under Koozali SME Server.
For direct post install purpose we user a e-smith-base RPM owned file : /usr/lib/systemd/system-preset/50-Koozali.preset
For direct post-install purposes we use an e-smith-base RPM own file : /usr/lib/systemd/system-preset/50-Koozali.preset
This file contains a list of service we want to have enabled or disabled.
This file contains a list of service we want to have enabled or disabled.
Another file will take precedence without hiding it: /etc/systemd/system-preset/49-koozali.preset. This file is templated, and use the e-smith configuration db to list services that should be enabled or disabled based on admin changes.
Another file will take precedence without hiding it: /etc/systemd/system-preset/49-koozali.preset. This file is templated, and uses the e-smith configuration db to list services that should be enabled or disabled based on admin changes.
It is important that this file is called 49-koozali.preset (k or K?) and not 50-Koozali.preset, so it does not hide 50-Koozali.preset content, but take precedence on it. Hence, anything not declared in 49-koozali.preset will take the state of what declare the 50 one. <!-- k or K? -->
Then we use an action script to default all we want in systemd: /etc/e-smith/events/actions/systemd-default<syntaxhighlight lang="bash">
Then we use an action script to default all we want to be in systemd: /etc/e-smith/events/actions/systemd-default<syntaxhighlight lang="bash">
#!/usr/bin/bash
#!/usr/bin/bash
/usr/bin/systemctl enable sme-server.target
/usr/bin/systemctl enable sme-server.target
/usr/bin/systemctl set-default sme-server.target
/usr/bin/systemctl set-default sme-server.target
</syntaxhighlight>This will ensure that on every run, all service explicitly enabled or disabled in the configuration db are declared this way in systemd, and if they are not in the db they be according to what is declared in other /lib/systemd/system-preset/* files.
</syntaxhighlight>This will ensure that on every run, all services explicitly enabled or disabled in the configuration db are declared this way in systemd, and if they are not in the db they are controlled according to what is declared in other /lib/systemd/system-preset/* files.
Any services not explicitly declared there will be disabled (/lib/systemd/system-preset/99-default-disable.preset). So If you want a service to run you need to declare it at the very least with :<syntaxhighlight lang="bash">
Any services not explicitly declared there will be disabled (/lib/systemd/system-preset/99-default-disable.preset). So If you want a service to run you need to declare it at the very least with :<syntaxhighlight lang="bash">
db configuration set myservice service status enabled
db configuration set myservice service status enabled
</syntaxhighlight>
</syntaxhighlight>
Note you can also declare a service unit name with a service name with a different name. This is beta for the moment, it might conflict with some other script handling the services (/sbin/e-smith/service, bootstrap-console; controlService perl function from /usr/share/perl5/vendor_perl/esmith/util.pm) <syntaxhighlight lang="bash">
Note you can also declare a service unit name with a service name with a different name. This is in beta for the moment, as it might conflict with some other script handling the services (/sbin/e-smith/service, bootstrap-console; controlService perl function from /usr/share/perl5/vendor_perl/esmith/util.pm) <syntaxhighlight lang="bash">
db configuration set myservice service status enabled SystemdUnit service@my.service
db configuration set myservice service status enabled SystemdUnit service@my.service
expand-template /etc/systemd/system/preset/49-koozali.preset
expand-template /etc/systemd/system-preset/49-koozali.preset
</syntaxhighlight>
</syntaxhighlight>
==== service-status ====
====service-status====
We use as ExecStartPre a call to a script preventing any unwanted launch of a disabled service. This is pretty radical and jsut fails the service with a message at any trial to start it. This is in case one starts it manually or has it enabled and prevent an event to run to disable it before reboot.
We run as ExecStartPre a call to a script preventing any unwanted launch of a disabled service. This is basic and just fails the service with a message at any attempt to start it. This deals with the case that it has been started manually, or has been enabled, and prevents an event from running to disable it before reboot (is this correct?)
Currently the script just fails, but we could imagine in a future to have a property in the db to make it just send a warning and let the service start.<syntaxhighlight lang="bash">
Currently the script just fails, but we could in the future have a property in the db to make it just send a warning and let the service start.<syntaxhighlight lang="bash">
#! /bin/sh
#! /bin/sh
</syntaxhighlight>
</syntaxhighlight>
==== services2adjust ====
====services2adjust====
Runit and Sysvinit were allowing some signals that are not handled anymore by systemd. We will have to replace those.
Runit and Sysvinit were allowing some signals that are not handled anymore by systemd. We will have to replace those.
'''As an example <u>service masq adjust</u> need to be replaced by <u>systemctl reload masq.service</u>.'''
'''As an example <u>service masq adjust</u> needs to be replaced by <u>systemctl reload masq.service</u>.'''
for the following we could use <code>kill --signal=</code>
for the following we could use <code>kill --signal=</code>
On the other hand, systemd offers few newer interesting solutions :
*sigusr1
* start
*sigusr2
* stop
*sigterm
* reload
*sighup
* restart
* try-restart
On the other hand, systemd offers some interesting new solutions :
* reload-or-restart
* try-reload-or-restart
*start
*stop
*reload
*restart
*try-restart
*reload-or-restart
*reload-or-try-restart
===Service migration===
*We will have all our service unit files in /usr/lib/systemd/system/
*They should all be required by sme-server.target in the [Install]
*For as long as possible we will avoid templating .service files and/or their modification in /usr/lib/systemd/system/servicename.service.d/50koozali.conf
===== Previous pure Syvinit service, without a provided systemd unit =====
=====Previous pure Syvinit service, with a provided systemd unit=====
If we are lucky we can simply use the ones provided as a replacement, we add a service.d/50koozali.conf for the service and alter it in the way we need.
'''The template will need to be expanded for ''package''-update, bootstrap-console-save, console-save, post-install, post-upgrade at least'''
you will need to plan a createlinks addition :<syntaxhighlight lang="perl">
#smeserver-dovecot-update
my $event="smeserver-dovecot-update";
# services to adjust
safe_symlink("restart", "root/etc/e-smith/events/$event/services2adjust/dovecot");
safe_symlink("restart", "root/etc/e-smith/events/$event/services2adjust/rsyslog");
# specific actions we want for this package
event_link("adjust-dovecot", $event, "02");
# systemd-specific action mandatory for this package-update event
event_link("systemd-reload", $event, "89");
event_link("systemd-default", $event, "88");
# specific template we will need for this package
templates2events("/etc/rsyslog.conf",$event);
# systemd-specific template mandatory for this package-update event
templates2events("/usr/lib/systemd/system/dovecot.service.d/50koozali.conf", ($event, qw(bootstrap-console-save console-save post-install post-upgrade) ));
</syntaxhighlight>
Usually we then create 3 fragments
*/etc/e-smith/templates/usr/lib/systemd/system/nut-monitor.service.d/50koozali.conf/20unit
<syntaxhighlight lang="bash">
[Unit]
#this could be omitted, very specific to the nut service
PartOf=nut.service
After=nut.service
</syntaxhighlight>
*/etc/e-smith/templates/usr/lib/systemd/system/nut-monitor.service.d/50koozali.conf/40service
<syntaxhighlight lang="bash">
[Service]
# reset all ExecStartPre
ExecStartPre=
# add our own
ExecStartPre=/sbin/e-smith/service-status nut
# ignore this one if it fails
ExecStartPre=-/bin/mytest
# reset previous Start
ExecStart=
# do our own
ExecStart=/bin/sv u helo
</syntaxhighlight>
*/etc/e-smith/templates/usr/lib/systemd/system/nut-monitor.service.d/50koozali.conf/80install
<syntaxhighlight lang="bash">
[Install]
#probably the most wanted part !
WantedBy=sme-server.target
</syntaxhighlight>
You will then need to create the destination path in the spec file in %build
mkdir -p root/usr/lib/systemd/system/nut-monitor.service.d/50koozali.conf
Finally, think to remove any remains of previous sysvinit as it might prevent the service to enable in /etc/systemd/system-preset/49-koozali.preset. to enable the service all the conditions should be met:
*a key $key in configuration db should exist as type=service and status=enabled
*a file $key.service should exist in /usr/lib/systemd/system/ or in /etc/systemd/system/
*there should be no file /etc/rc.d/init.d/$key nor /etc/rc.d/init.d/supervise/$key
{{Warning box|1=we use preset-all to enable our services, however there is a bug in systemd up to v236 (up to Rhel8). With this bug drop in configuraiton file sin *.service.d/ are ignored when systemctl search for [Install] content to do preset-all.
As a result our WantedBy=sme-server.target are igored
we write a replacement with systemd-default action script, but this one has also limits:
# works only with sme-server.target
# does not check really where is the WantedBy, if it'S elsewhere than the expected [Install] section it will use it as well
# does not work with templated unit (@.service)}}
=====Previous pure Syvinit service, without a provided systemd unit=====
Here is the example of masq : /lib/systemd/system/masq.service<syntaxhighlight lang="bash">
Here is the example of masq : /lib/systemd/system/masq.service<syntaxhighlight lang="bash">
[Unit]
[Unit]
</syntaxhighlight>
</syntaxhighlight>
===== Previous Runit service, with a provided systemd unit =====
=====Previous Runit service, with a provided systemd unit=====
If we are lucky we can simply use the ones provided as a replacement, we add a service.d/50koozali.conf for the service and alter it in the way we need.
As a last resort we could hide the whole file using the service.d/50koozali.conf and simply call runit, see the next example.
see [[#Previous pure Syvinit service, with a provided systemd unit]] for reference...
===== Previous Runit service, without a provided systemd uni =====
=====Previous Runit service, without a provided systemd unit=====
example of wan : /lib/systemd/system/wan.service<syntaxhighlight lang="bash">
example of wan : /lib/systemd/system/wan.service<syntaxhighlight lang="bash">
[Unit]
[Unit]
</syntaxhighlight>
</syntaxhighlight>
=== References ===
===References===
<references />
<references />
[[Category:SME10-Development]]
[[Category:SME10-Development]]