Linux Services Skill

Manage systemd services and access logs safely.

See also: Shared Conventions | Safety Guidelines

Purpose

Check service status, view logs, and restart services when needed.

Commands

Service Status

systemctl status <service>
systemctl is-active <service>
systemctl is-enabled <service>
systemctl list-units --type=service --state=running

Service Control

systemctl start <service>
systemctl stop <service>
systemctl restart <service>
systemctl reload <service>

Log Access

journalctl -u <service> --no-pager -n 200
journalctl -u <service> --since "1 hour ago" --no-pager
journalctl -u <service> -f  # follow

Service Restart Protocol

Before restarting any service:

1. Capture current status

   systemctl status myapp
   

2. Capture recent logs

   journalctl -u myapp --no-pager -n 50
   

3. Present findings to user

4. Restart (only after acknowledgment)

   systemctl restart myapp
   

5. Verify service started

   systemctl status myapp
   

Workflow: Diagnose Service Issues

# 1. Check if service is running
systemctl is-active myapp

# 2. Get detailed status
systemctl status myapp

# 3. Check recent logs for errors
journalctl -u myapp --no-pager -n 100 | grep -i error

# 4. Check when it last started
systemctl show myapp --property=ActiveEnterTimestamp

Workflow: Safe Restart

# 1. Pre-restart state
systemctl status myapp
journalctl -u myapp --no-pager -n 20

# 2. Restart
systemctl restart myapp

# 3. Verify
sleep 2
systemctl status myapp
journalctl -u myapp --since "1 minute ago" --no-pager

Policies

• Capture state before restart - always log pre-restart status
• Verify after restart - confirm service is healthy
• No blind restarts - understand why restart is needed
• Critical services - extra caution with database, auth, networking services
• Report any failed restarts with full log output