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=systemd changes= | =systemd changes= | ||
===systemctl=== | ===systemctl=== | ||
====Filtering by unit state=== | |||
`systemctl` now supports filtering the unit list output by load state. The --state option will accept any value or a comma-separated list values of LOAD, SUB, or ACTIVE states. For example: | `systemctl` now supports filtering the unit list output by load state. The --state option will accept any value or a comma-separated list values of LOAD, SUB, or ACTIVE states. For example: | ||
systemctl --state failed | systemctl --state failed | ||
===journalctl=== | |||
====Viewing the logs of a specific boot==== | |||
`journalctl -b` can be used to look for boot output of a specific boot. For example: | |||
journalctl -b # output from current boot | |||
journalctl -b -1 #output from previous boot | |||
In addition to relative boot sequence, journalctl assigns a 128bit boot ID that can be referenced. For example, | |||
journalctl -b 38fd9c3303574ed38e822233457f6b77 # output from a specific designated boot | |||
===Referencing the journal with 'cursors'=== | |||
journalctl can reference the contents of the journal by a record identifier known as a 'cursor'. Similar to a git hash, the cursor uniquely identifies a point in the journal. | |||
If you add --show-cursor to a journalctl query, the last line of output will contain the cursor value: | |||
journalctl -b -u network --show-cursor --since 15:00 | |||
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 | |||
The cursor can be used to identify that point in the journal in a broader query to provide context: | |||
journalctl -c "s=13497722134642a2ac1544bada0c8836;i=1120d;b=8491c05dabd3444ca122e7069b5de0a9;m=db2118a46;t=4e5e7d81c7402;x=d177768ac95df831" | |||
Scripts parsing journalctl's output can store the cursor value and use it on their next run to pick up where they left off: | |||
journalctl --after-cursor "s=13497722134642a2ac1544bada0c8836;i=1120d;b=8491c05dabd3444ca122e7069b5de0a9;m=db2118a46;t=4e5e7d81c7402;x=d177768ac95df831" | |||
| Line 15: | Line 40: | ||
[[Category:Draft documentation]] | [[Category:Draft documentation]] | ||
[[Category:Documentation beats]] | [[Category:Documentation beats]] | ||
<!-- There's a bit about journalctl cursor seeking, but I can't find a documented definition of 'cursor' or any usage examples. It appears to be for machine users of the journal only. --> | |||
Revision as of 00:06, 9 September 2013
Beat is open
This beat is now ready to have Fedora 25 content added by the beat writer
This beat is now ready to have Fedora 25 content added by the beat writer
systemd changes
systemctl
=Filtering by unit state
systemctl now supports filtering the unit list output by load state. The --state option will accept any value or a comma-separated list values of LOAD, SUB, or ACTIVE states. For example:
systemctl --state failed
journalctl
Viewing the logs of a specific boot
journalctl -b can be used to look for boot output of a specific boot. For example:
journalctl -b # output from current boot journalctl -b -1 #output from previous boot
In addition to relative boot sequence, journalctl assigns a 128bit boot ID that can be referenced. For example,
journalctl -b 38fd9c3303574ed38e822233457f6b77 # output from a specific designated boot
Referencing the journal with 'cursors'
journalctl can reference the contents of the journal by a record identifier known as a 'cursor'. Similar to a git hash, the cursor uniquely identifies a point in the journal.
If you add --show-cursor to a journalctl query, the last line of output will contain the cursor value:
journalctl -b -u network --show-cursor --since 15:00 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
The cursor can be used to identify that point in the journal in a broader query to provide context:
journalctl -c "s=13497722134642a2ac1544bada0c8836;i=1120d;b=8491c05dabd3444ca122e7069b5de0a9;m=db2118a46;t=4e5e7d81c7402;x=d177768ac95df831"
Scripts parsing journalctl's output can store the cursor value and use it on their next run to pick up where they left off:
journalctl --after-cursor "s=13497722134642a2ac1544bada0c8836;i=1120d;b=8491c05dabd3444ca122e7069b5de0a9;m=db2118a46;t=4e5e7d81c7402;x=d177768ac95df831"