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Incorporated review feedback in restart concept.

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Signed-off-by: MCamp859 <mary.camp@ptiglobal.net>
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MCamp859
2018-04-04 17:56:13 -04:00
parent 2e8a607a34
commit ece2cbab30
1 changed files with 39 additions and 39 deletions
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source/clear-linux/concepts/restart.rst
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@@ -8,10 +8,10 @@ deployed, and includes how to replace or update software. A good OS
provides tools for the entire software life cycle. These tools must include
ways to remove software components properly when replaced with something else.
Most of the work on software update code in |CL| has primarily focused on
adding new software to the system. We recommend that users reboot their system
once in a while, but we did not provide any tools to restart services easily,
until now.
Most of the work on software update code in |CL| was focused on adding new
software to the system. We recommended that users reboot their system once in
a while, but we did not provide any tools to restart services easily, until
now.
User challenges
***************
@@ -29,13 +29,11 @@ solutions such as the following:
* Mark updates requiring a reboot, such as kernel updates.
* Inform the user of those updates.
* Ask the user to restart.
* Ask the user to restart the OS.
Both solutions are acceptable for many OSes. However, |CL| updates software
automatically and users do not see notices from the updater unless they review
the journal.
|CL| requires a completely different solution, with the following
the journal. |CL| requires a completely different solution, with the following
requirements:
* Eliminate the guesswork about what to restart and under what circumstances.
@@ -43,16 +41,17 @@ requirements:
background restart.
* Fit into the |CL| architectural perspective: be small, quick, and lean.
:command:`clr-service-restart` functionality
********************************************
clr-service-restart functionality
*********************************
Typical reasons to restart a service daemon include:
* A new version replaces the executable file itself.
* A new version replaces a library component used by a service daemon.
Our method restarts daemons for both cases by reading various files in the
:file:`procfs` filesystem provided by the kernel.
Our method restarts daemons when it is really needed, especially
in the case of security updates. The tool restarts daemons by reading
various files in the :file:`procfs` filesystem provided by the kernel.
The second part of the problem is to determine whether or not running
processes are part of a system service. The tool focuses on system services
@@ -60,36 +59,37 @@ because most system services are background tasks with no direct user
interaction. Fortunately, :command:`systemd` provides a simple way to:
* Determine which active tasks are within the system domain.
* Determine which service daemon maps to the task.
* Determine which tasks map to which service.
We combined both solutions into a low-overhead tool that shows which system
daemons require a restart, as shown below:
Figure 1: Invoke :command:`clr-service-restart`.
Figure 1: Invoke :command:`clr-service-restart`.
.. code-block:: bash
.. code-block:: bash
sudo clr-service-restart -a -n
sudo clr-service-restart -a -n
.. code-block:: console
.. code-block:: console
upower.service: needs a restart (a library dependency was updated)
/usr/bin/systemctl --no-ask-password try-restart upower.service
NetworkManager.service: needs a restart (a library dependency was
updated)
/usr/bin/systemctl --no-ask-password try-restart NetworkManager.service
....
upower.service: needs a restart (a library dependency was updated)
/usr/bin/systemctl --no-ask-password try-restart upower.service
NetworkManager.service: needs a restart (a library dependency was
updated)
/usr/bin/systemctl --no-ask-password try-restart NetworkManager.service
....
:command:`clr-service-restart` implements a whitelist to identify which
daemons can be restarted. The system administrator maintains a customized
overlay of the default |CL| OS whitelist. When a software update occurs,
daemons can be restarted. The system administrator can customize the default
|CL| OS whitelist using :option:`allow` or :option:`disallow` options for
restarting system services. When a software update occurs,
:command:`clr-service-restart` consults the whitelist to see if a service
daemon is allowed to be restarted or not. See the options section below for
daemon is allowed to be restarted or not. See the options section for
details.
Options for :command:`clr-service-restart`
******************************************
Options for clr-service-restart
*******************************
The :option:`allow` option identifies a daemon to restart after an OS software
update. The :command:`clr-service-restart` daemon creates a symlink in
@@ -97,9 +97,9 @@ update. The :command:`clr-service-restart` daemon creates a symlink in
:command:`clr-service-restart` to restart the :option:`tallow` daemon after an
OS software update.
.. code-block:: bash
.. code-block:: bash
sudo clr-service-restart allow tallow.service
sudo clr-service-restart allow tallow.service
The :option:`disallow` option tells :command:`clr-service-restart` not to
restart the specified daemon even if the OS defaults permit the daemon to be
@@ -108,9 +108,9 @@ restarted. The :command:`clr-service-restart` daemon creates a symlink in
The example below tells :command:`clr-service-restart` not to restart the
:option:`rngd` daemon after an OS software update.
.. code-block:: bash
.. code-block:: bash
sudo clr-service-restart disallow rngd
sudo clr-service-restart disallow rngd
The :option:`default` option makes :command:`clr-service-restart` revert back
to the OS defaults and delete any symlink in :file:`/etc/clr-service-restart`.
@@ -118,12 +118,12 @@ The example below tells :command:`clr-service-restart` to restart
:option:`rngd` automatically again, because :option:`rngd` is whitelisted for
automatic service restarts by default in |CL|.
.. code-block:: bash
.. code-block:: bash
sudo clr-service-restart default rngd
sudo clr-service-restart default rngd
Monitor options for :command:`clr-service-restart`
==================================================
Monitor options for clr-service-restart
=======================================
:command:`clr-service-restart` works in the background and is invoked with
:command:`swupd` automatically. Review the journal output to verify that
@@ -132,7 +132,7 @@ services are restarted after an OS software update.
To monitor :command:`clr-service-restart`, use one or both options described
below.
:option:`-n`
:option:`-n`
This option makes :command:`clr-service-restart` perform no restarts. Instead
it displays the services that could potentially be restarted. When used,
@@ -143,7 +143,7 @@ it displays the services that could potentially be restarted. When used,
* Why it needs a restart.
* Which command is required to restart the unit.
:option:`-a`
:option:`-a`
This option makes :command:`clr-service-restart` consider all system services,
not only the ones that are whitelisted. Because the default whitelist in |CL|
@@ -181,4 +181,4 @@ your work easier. We made a github project of :command:`clr-service-restart`
and we invite you to look at the code, share your thoughts, and work with us
on improving the project. You can find the project at:
https://github.com/clearlinux/clr-service-restart
https://github.com/clearlinux/clr-service-restart