https://github.com/clearlinux/clr-service-restart

Automatically restart system services that need restarting after software updates.
https://github.com/clearlinux/clr-service-restart

software-update systemd systemd-service

Last synced: 3 months ago
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Automatically restart system services that need restarting after software updates.

• Host: GitHub
• URL: https://github.com/clearlinux/clr-service-restart
• Owner: clearlinux
• License: gpl-3.0
• Created: 2018-01-16T17:41:58.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2025-01-08T22:57:02.000Z (over 1 year ago)
• Last Synced: 2025-07-19T22:00:06.449Z (11 months ago)
• Topics: software-update, systemd, systemd-service
• Language: C
• Size: 30.3 KB
• Stars: 9
• Watchers: 3
• Forks: 2
• Open Issues: 5
• Metadata Files:
  • Readme: README.md
  • License: COPYING

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README

          
## DISCONTINUATION OF PROJECT. 

This project will no longer be maintained by Intel. 

Intel will not provide or guarantee development of or support for this project, including but not limited to, maintenance, bug fixes, new releases or updates. Patches to this project are no longer accepted by Intel. If you have an ongoing need to use this project, are interested in independently developing it, or would like to maintain patches for the community, please create your own fork of the project.

Contact: webadmin@linux.intel.com  

## clr-service-restart

A program that restarts systemd services that are using software

components that have been updated.

## How it works

The Linux kernel maintains information about running processes in the

`procfs` filesystem. This information can be used to identify processes

that are using resources that are no longer physically present on

the file system, such as when a binary or system library is updated.

Any software update causes the kernel to see that a reference to a

binary or a reference to a library is no longer corresponding with the

actual current version of the library or binary on the filesystem. If

this happens, the kernel will mark the `procfs` entries for those

references as `(deleted)`. Specifically the `exe` symlink will get

marked in this way if the binary is updated, and the `maps` file will

get updated in this way if a library component is updated.

Using these references, we now know which programs are currently being

executed that are holding references to outdated libraries or binaries,

and therefore should be restarted.

However, we do not want to restart programs that are not part of a

system unit, or in some other way are not part of the system domain. In

order to avoid considering all processes running for the purpose of

restarting them, we restrict consideration to only those processes

that are listed as active `tasks` in the systemd `system.slice`

hierarchy maintained under `/sys/fs/cgroup/systemd/`. This hierarchy

only contains units (and therefore tasks) in the system domain and

excludes user units or user programs.

## Configuration

It's extremely risky to restart all units unconditionally since some

units may require specific ordering, interaction or other factors

to be considered. By default, this program will not restart any

service automatically, and will only consider units that have been

explicitly marked as `allowed` by either the local administrator

or the distribution. This is done through maintaining symlinks in

`/usr/share/clr-service-restart` and `/etc/clr-service-restart`. If a

valid symlink is found in these folders, the unit will be considered

for restarting. If a symlink is found in `/etc/clr-service-restart`

with the name of a unit pointing to `/dev/null` it will be

omitted for consideration and not be restarted. Links in the

`/etc/clr-service-restart` location take precedence over those in

`/usr/share/clr-service-restart`. Links to `/dev/null` in the

`/usr/share/clr-service-restart` location are invalid.

## Commands

These symlinks can be manipulated by the local administrator with the

`clr-service-restart` program, which understands the following 3

commands:

 * `allow "foo.service"`:

   Mark "foo.service" as restartable.

 * `disallow "bar.service"`:

   Mark "bar.service" as not restartable.

 * `default "baz.service"`:

   Remove local preferences and revert to the distribution default

   for "baz.service".

If `clr-service-restart` is executed without any commands, it will

restart all services that are marked `allow` for restart.

## Options

The following options are understood. These options may not be used

together with the `allow`, `disallow` and `default` commands.

 * `-n`:

   Don't actually perform any restarts, just show what would happen

   if the program would execute normally. This makes the program

   more verbose.

 * `-a`:

   Consider all system units. With this option, all system units that

   are running will be considered for restarting. This should normally

   only be done interactively, and never in an automated fashion.

## Bugs

Please report bugs to: `dev@lists.clearlinux.org`

## License

Copyright © 2018 Intel Corporation

Author: Auke-jan H. Kok ``

This program is free software: you can redistribute it and/or modify

it under the terms of the GNU General Public License as published

by the Free Software Foundation, either version 3 of the License,

or (at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program. If not, see .