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Challengelinux

Linux Processes, Services & Logs — Challenge

Find the process, read what it actually said, and restore a service that will not start.

Time
22 min
Level
Beginner
Objectives
4 objectives
Cost
Free

Before you start

You will need

  • Linux with systemd
  • sudo access

You will be able to

  • Locate a process by port, name or open file
  • Read a service's own logs rather than guessing from its status
  • Tell a crash apart from a configuration error

CostFree

— any Linux machine, VM or container.

You are done when

0 of 4

The goal#

Achieve the same outcome as Linux Processes, Services & Logs, from an empty starting point, without the steps.

A service is down. systemctl status says failed, which tells you that it failed and nothing about why.

This lab builds the sequence that gets from that word to the cause.

What must be true when you are done#

  • You can name the PID holding a given port, and the command that told you.
  • You can show the last 50 log lines for one service without reading the whole journal.
  • A deliberately broken service is diagnosed from its logs and restored.
  • You can explain the difference between failed, inactive and activating.

Rules#

  • Do not open the guided lab until you are finished, or until the same problem has held you up for 20 minutes.
  • Documentation is allowed and encouraged.
  • Verify every criterion with a command whose output you can read.

If you get stuck#

  1. What did you expect, exactly?
  2. What happened instead — the error text, not a paraphrase?
  3. Which layer is that error from?
  4. What is the smallest command that proves the layer below is fine?

The concept behind it

Stuck?Open the guided lab

Next up

Lab 2 of 58 on the project path

Linux Security & SSH HardeningLock down SSH without locking yourself out, and know how to recover when you inevitably do.45 minBeginner