commit 685e46c90a7ab7d0139b246d7c1381376cb907b5
Author: Pete Travis <immanetize(a)fedoraproject.org>
Date: Sun Oct 20 11:02:42 2013 -0600
added some info about journalctl and systemd
en-US/System_Daemons.xml | 75 ++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 72 insertions(+), 3 deletions(-)
---
diff --git a/en-US/System_Daemons.xml b/en-US/System_Daemons.xml
index 843bc51..7b86306 100644
--- a/en-US/System_Daemons.xml
+++ b/en-US/System_Daemons.xml
@@ -110,10 +110,27 @@
Services can be added to a slice with the
<function>Slice=<replaceable>slicename</replaceable></function>
directive in their unit configuration file. Arguments allowing resource limitation within
a slice or service unit are described in <command>man
systemd.directives</command>. See also <command>man
systemd.slice</command> and <command>man systemd.cgroup</command>.
</para>
</section>
+ <section id="system_daemons-systemd-truecrypt">
+ <title>systemd-cryptsetup for TrueCrypt</title>
+ <para>
+ Support for <productname>TrueCrypt</productname> in Fedora is expanded by
<application>systemd-cryptsetup</application> support for the technology,
allowing easy authentication during boot.
+ </para>
+ </section>
-
+ <section id="system_daemons-systemd-filter">
+ <title>Filtering by unit state with systemctl</title>
+ <para>
+ <command>systemctl</command> now supports filtering the unit list output by
load state. The <function>--state</function> option will accept any value or a
comma-separated list of the values of <function>LOAD</function>,
<function>SUB</function>, or <function>ACTIVE</function> states.
For example,
+ <screen>
+ <command>
+ systemctl --state failed
+ </command>
+ </screen>
+ </para>
+ </section>
</section>
- <section>
+
+ <section id="system_daemons-journald">
<title>journald</title>
<indexterm>
<primary>journald</primary>
@@ -121,8 +138,60 @@
<indexterm>
<primary>journalctl</primary>
</indexterm>
-
<para />
+ <section id="system_daemons-journald-b">
+ <title>Viewing the logs of a specific boot</title>
+ <para>
+ <command>journalctl</command> can now be used to view the logs from a
specific boot. For example, to view logs from the current boot:
+ <screen>
+ <command>journalctl -b</command>
+ </screen>
+ </para>
+ <para>
+ Or, view the logs from the previous boot:
+ <screen>
+ <command>journalctl -b -1</command>
+ </screen>
+ </para>
+ <para>
+ In addition to relative boot sequence, journald assigns a 128-bit boot ID that can be
referenced. For example:
+ <screen>
+ <command>journalctl -b 38fd9c3303574ed38e822233457f6b77</command>
+ </screen>
+ </para>
+ </section>
+ <section id="system_daemons-journald-cursors">
+ <title>Referencing the journal with cursors</title>
+ <para>
+ <command>journalctl</command> can reference the contents of the journal by a
record identifier known as a <literal>cursor</literal>. Similar to a git hash,
the <literal>cursor</literal> uniquely identifies a point in the journal.
+ </para>
+ <para>
+ If you add <function>--show-cursor</function> to a journalctl query, the
last line of output will contain the cursor value:
+ <screen>
+ <command>journalctl -b -u network --show-cursor --since 15:00</command>
+ Sep 08 15:37:59 localhost.localdomain network[4074]: [FAILED]
+ Sep 08 15:37:59 localhost.localdomain systemd[1]: network.service: control process
exited, code=exited status=1
+ Sep 08 15:37:59 localhost.localdomain systemd[1]: Failed to start LSB: Bring up/down
networking.
+ Sep 08 15:37:59 localhost.localdomain systemd[1]: Unit network.service entered failed
state.
+ -- cursor:
s=13497722134642a2ac1544bada0c8836;i=1120d;b=8491c05dabd3444ca122e7069b5de0a9;m=db2118a46;t=4e5e7d81c7402;x=d177768ac95df831
+ </screen>
+ </para>
+ <para>
+ The cursor can be used to identify that point in the journal in a broader query to
provide context:
+ <screen>
+ <command>journalctl -c
"s=13497722134642a2ac1544bada0c8836;i=1120d;b=8491c05dabd3444ca122e7069b5de0a9;m=db2118a46;t=4e5e7d81c7402;x=d177768ac95df831"</command>
+ </screen>
+ </para>
+ <para>
+ Scripts parsing journalctl's output can store the cursor value and use it on their
next run to pick up where they left off:
+ <screen>
+ <command>journalctl --after-cursor
"s=13497722134642a2ac1544bada0c8836;i=1120d;b=8491c05dabd3444ca122e7069b5de0a9;m=db2118a46;t=4e5e7d81c7402;x=d177768ac95df831"</command>
+ </screen>
+ </para>
+ </section>
+
+
+
</section>
</section>
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