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I am new to systemd.

I have read that along with systemd boot system comes it's own logging daemon - journald. But there is also a lot of mention of systemd-journald daemon over the Internet.

At first glance, I couldn't discern any differences between the two daemons. They appear to be aliases of each other. However, I might be mistaken.

Could someone please clarify and explain any distinctions between these two daemons?

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2 Answers 2

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journald and systemd-journald are the same notion.

journald is often used as a shorthand for systemd-journald, which is the logging component of the systemd system and service manager.

Systemd is a suite of software that provides fundamental building blocks for managing and controlling the Linux operating system.
It includes various components, including systemd-journald, which is responsible for collecting, storing, and retrieving log data.

systemd-journald is the name of the daemon process that runs journald. It is the specific instance of the journald daemon that is launched and managed by systemd.

journald is the concept of the logging component, while systemd-journald is the specific instance of the daemon responsible for executing the logging functionality.

journald and systemd-journald refer to the same daemon, and they are used interchangeably to denote the logging functionality provided by systemd.

https://www.freedesktop.org/software/systemd/man/systemd-journald.service.html

journald.conf, journald.conf.d, [email protected] — Journal service configuration files

Tutorial: Logging with journald

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  • To clarify a bit further, systemd-journald is the only journald implementation right now (and this is likely to remain the case, most developers who would be inclined to write an alternative recognize the numerous inherent issues with it as simply making it not worth it), so making a differentiation between the two concepts makes little sense, unlike with, for example, logind. Jul 2, 2023 at 19:35
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Yes, both are the same. systemd-journald is the name of the service running the journald daemon:

$ systemctl status systemd-journald
● systemd-journald.service - Journal Service
   Loaded: loaded (/usr/lib/systemd/system/systemd-journald.service; static; vendor preset: disabled)
   Active: active (running) since Wed 2023-03-29 14:25:45 IDT; 3 months 3 days ago
     Docs: man:systemd-journald.service(8)
           man:journald.conf(5)
 Main PID: 435 (systemd-journal)
   Status: "Processing requests..."
    Tasks: 1 (limit: 512)
   CGroup: /system.slice/systemd-journald.service
           └─435 /usr/lib/systemd/systemd-journald

And also the name of the command to run the daemon and the name of the daemon process.

$ ps -fC systemd-journald
UID        PID  PPID  C STIME TTY          TIME CMD
root       435     1  0 Mar29 ?        00:50:36 /usr/lib/systemd/systemd-journald

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