RYZHOV / Linux
A working reference for Linux

Services & logs

Trace failed units, boot dependencies, journal messages, and service permissions.

A failed service is a symptom. Read the unit definition and the relevant journal together before changing restart policies or permissions. These versioned manuals describe systemd as packaged for Debian 12; compare them with man pages on your own host.

Where to start

Use systemctl to identify the unit state, journalctl to narrow the time window, then systemd.service and systemd.exec to interpret startup and execution settings. Consult systemd.unit for ordering and dependencies.

6 resources

Trace failed units, boot dependencies, journal messages, and service permissions.

  • systemctl: inspect and control units

    Inspect a unit's state and configuration, and distinguish reloading manager configuration from restarting a service.

    Referencesystemd / Debianmanpages.debian.org
    systemd 252 · Debian 12 · Distribution reference · Selection reviewed
  • journalctl: focus the evidence

    Filter the journal by service, boot, priority, and time when a failure is hidden in unrelated log messages.

    Referencesystemd / Debianmanpages.debian.org
    systemd 252 · Debian 12 · Distribution reference · Selection reviewed
  • Service startup and restart behavior

    Interpret service types, startup commands, timeouts, and restart behavior when a daemon exits or never becomes ready.

    Referencesystemd / Debianmanpages.debian.org
    systemd 252 · Debian 12 · Distribution reference · Selection reviewed
  • Service execution environment

    Investigate working directories, users, environment files, resource restrictions, and sandbox settings that affect a service process.

    Referencesystemd / Debianmanpages.debian.org
    systemd 252 · Debian 12 · Distribution reference · Selection reviewed
  • Unit dependencies and ordering

    Separate requirement dependencies from startup ordering and understand how drop-ins modify an existing unit.

    Referencesystemd / Debianmanpages.debian.org
    systemd 252 · Debian 12 · Distribution reference · Selection reviewed
  • Analyze boot and unit configuration

    Inspect boot timing and validate unit definitions; use the results as evidence rather than treating the longest duration as proof of a fault.

    Referencesystemd / Debianmanpages.debian.org
    systemd 252 · Debian 12 · Distribution reference · Selection reviewed

How this library is selected

References are selected for a concrete operational task, with preference for project and distribution documentation. Annotations describe when to use a source; version labels make its scope explicit.

Selection reviewed means the destination, subject, and version scope were checked. It is not a claim that every upstream command has been tested. Original guides identify their own test environment. Platform filters also include references that apply across distributions.