Difference between revisions of "Journalctl"
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<code>journalctl</code> command allows to query the contents of the [[systemd]] journal/[[logs]]. | <code>journalctl</code> command allows to query the contents of the [[systemd]] journal/[[logs]]. | ||
== Configuration == | == Configuration == | ||
| − | * <code>[[/etc/systemd/ | + | * <code>[[/etc/systemd/journald.conf]]</code> |
== Basic Commands == | == Basic Commands == | ||
| − | * <code>journalctl</code><ref>https://www.freedesktop.org/software/systemd/man/journalctl.html</ref> or <code>journalctl --no-pager</code> | + | * <code>journalctl</code><ref>https://www.freedesktop.org/software/systemd/man/journalctl.html</ref> or <code>journalctl --[[no-pager]]</code> |
| − | * <code>journalctl -r</code> (reverse order) | + | * <code>[[journalctl -r]]</code> (reverse order) |
* <code>journalctl -k</code>: Show only [[kernel]] messages | * <code>journalctl -k</code>: Show only [[kernel]] messages | ||
| − | * <code>journalctl -f</code> (follow) | + | * <code>[[journalctl -f]]</code> (follow) |
* <code>[[journalctl -u]] [[service-name]].service</code> | * <code>[[journalctl -u]] [[service-name]].service</code> | ||
:: <code>-u unit_name</code> | :: <code>-u unit_name</code> | ||
| Line 15: | Line 16: | ||
::: <code>journalctl -u [[sshd|ssh]]</code> (See also [[sshd logs]]) | ::: <code>journalctl -u [[sshd|ssh]]</code> (See also [[sshd logs]]) | ||
::: <code>[[journalctl -u docker]]</code> | ::: <code>[[journalctl -u docker]]</code> | ||
| + | ::: <code>[[journalctl -u prometheus]]</code> | ||
| + | ::: <code>journalctl -u UNIT_NAME -n 1 -o verbose</code> | ||
* <code>[[journalctl --verify]]</code> | * <code>[[journalctl --verify]]</code> | ||
| − | Disk Usage/Logging: | + | [[journalctl -xn --nopager]] |
| + | |||
| + | [[Disk Usage]]/Logging: | ||
* <code>[[journalctl --disk-usage]]</code> | * <code>[[journalctl --disk-usage]]</code> | ||
* <code>journalctl --vacuum-time=2d</code> | * <code>journalctl --vacuum-time=2d</code> | ||
| − | * <code>journalctl --vacuum-size=200M</code><ref>https://askubuntu.com/a/1012913</ref> | + | * <code>[[journalctl --vacuum-size]]=200M</code><ref>https://askubuntu.com/a/1012913</ref> |
**--vacuum-size=BYTES Reduce disk usage below specified size | **--vacuum-size=BYTES Reduce disk usage below specified size | ||
**--vacuum-files=INT Leave only the specified number of journal files | **--vacuum-files=INT Leave only the specified number of journal files | ||
| − | **--vacuum-time=TIME Remove journal files older than specified time | + | **[[--vacuum-time]]=TIME Remove journal files older than specified time |
| − | * <code>journalctl --list-boots</code>. See also: <code>last (command)</code> | + | * <code>journalctl --list-boots</code>. See also: <code>[[last (command)]]</code> |
* <code>journalctl -xb</code> | * <code>journalctl -xb</code> | ||
:<code>-x --catalog</code> Includes explanations in log lines from [[message catalgog]] | :<code>-x --catalog</code> Includes explanations in log lines from [[message catalgog]] | ||
| − | :<code>-b </code> show message from current boot. if [ID] is provided will show messages from that specific [[boot]]. | + | :<code>-b </code> show message from current [[boot]]. if [ID] is provided will show messages from that specific [[boot]]. |
| + | |||
| + | |||
| + | * <code>journalctl --since "2 days ago"</code> | ||
| + | |||
| + | == Related terms == | ||
| + | * <code>[[docker run]] -d --[[log-driver]]=[[journald]] YOUR_CONTAINER</code> | ||
| + | * [[rsyslogd]] | ||
| + | * <code>journalctl --identifier=[[ignition]] --all</code> | ||
== Activities == | == Activities == | ||
| − | * Review [[ | + | * Review [[journalctl logs]] |
| − | |||
==See also== | ==See also== | ||
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* {{journalctl}} | * {{journalctl}} | ||
* {{systemd}} | * {{systemd}} | ||
| − | |||
* [[launchd]] init and operating system service management daemon for [[MacOS]] | * [[launchd]] init and operating system service management daemon for [[MacOS]] | ||
* {{logging}} | * {{logging}} | ||
| Line 48: | Line 59: | ||
[[Category:Linux]] | [[Category:Linux]] | ||
[[Category:Systemd]] | [[Category:Systemd]] | ||
| + | [[Category:journalctl]] | ||
Latest revision as of 12:05, 28 September 2023
journalctl command allows to query the contents of the systemd journal/logs.
Configuration[edit]
Basic Commands[edit]
journalctl[1] orjournalctl --no-pagerjournalctl -r(reverse order)journalctl -k: Show only kernel messagesjournalctl -f(follow)journalctl -u service-name.service
-u unit_namejournalctl -u service-name.service -fjournalctl -u libvirtdjournalctl -u ssh(See also sshd logs)journalctl -u dockerjournalctl -u prometheusjournalctl -u UNIT_NAME -n 1 -o verbose
journalctl -xn --nopager
Disk Usage/Logging:
journalctl --disk-usagejournalctl --vacuum-time=2djournalctl --vacuum-size=200M[2]- --vacuum-size=BYTES Reduce disk usage below specified size
- --vacuum-files=INT Leave only the specified number of journal files
- --vacuum-time=TIME Remove journal files older than specified time
journalctl --list-boots. See also:last (command)journalctl -xb
-x --catalogIncludes explanations in log lines from message catalgog-bshow message from current boot. if [ID] is provided will show messages from that specific boot.
journalctl --since "2 days ago"
Related terms[edit]
docker run -d --log-driver=journald YOUR_CONTAINER- rsyslogd
journalctl --identifier=ignition --all
Activities[edit]
- Review journalctl logs
See also[edit]
- journald:
journalctljournald.conf,journalctl --help,/dev/console - systemd-journald:
journalctl,/etc/systemd/journald.conf,journalctl logs,journalctl --list-boots,journalctl --disk-usage,journalctl -u kubelet,journalctl -u prometheus,journalctl --help - Systemd:
systemctl,systemd-journald,journalctlsystemd-cat,systemd-logind,systemd-networkd:networkctl,systemd-timesyncd,systemd-resolved,systemd-udevd[3],Systemd-logind: loginctl,hostnamectl,udevadm,systemd-run,portablectl,systemd-nspawn, systemd resource management, Timer (systemd), systemd logs,/etc/systemd/, systemd services,systemd-mount,/run/systemd/,.service,/usr/lib/systemd/,/usr/lib/systemd/system/,/usr/lib/systemd/system/systemd-resolved.service,/lib/systemd/, machinectl, systemd-oomd, systemd-analyze - launchd init and operating system service management daemon for MacOS
- Linux logging, Cisco IOS logging
du, du -hs, Disk space usage,df,ls,tree,find,docker system df,journalctl --disk-usage, No space left on device, ENOSPC,sar -F,growpart,resize2fs, ncdu, duf, dua-cli
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Source: https://en.wikiversity.org/wiki/Linux_Administration/System_Services/System_Logging/Journalctl
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