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LFCSEssential CommandsSingle Linux VMMedium

Fix a service that needs more file descriptors and less privilege

Scenario lfcs-cmd-004 · about 7 minutes · 8 points · 7 grader checks

A service refuses to start because of its open-file limit and running as root; fix it with a systemd drop-in, a dedicated system user and a memory cap.

  • systemd
  • drop-in
  • limits
  • ulimit
  • journalctl
  • service-user

What you will practise

  • Read why a service fails from the journal
  • Override unit settings with a drop-in instead of editing the unit
  • Set LimitNOFILE, User and MemoryMax for a service

Start this lab

With the CLI installed and signed in, this command provisions a fresh Ubuntu 24.04 LTS virtual machine on your Mac, applies the scenario setup and prints the task below.

goldenkube start lfcs-cmd-004

Task

The task text exactly as the CLI shows it. Solve it on the machine, then run goldenkube submit.

The service conn-pool.service fails to start. 1. Find out why from its logs and fix it so that it runs now and starts at boot. Do not edit /etc/systemd/system/conn-pool.service itself: put every change in a drop-in file. 2. The service must run as the system user connpool (create it: system account, no login shell, no home directory). 3. Limit the service's memory to 256 MiB. When it runs, http://127.0.0.1:8095/ answers ok.

Requirements and details

Certification
LFCS · Linux Foundation Certified System Administrator
Domain
Essential Commands
Difficulty
Medium
Environment
Single Linux VM
Recommended time
7 minutes
Points
8
Grader checks
7
Operating system
Ubuntu 24.04 LTS
Minimum CLI version
0.1.0
Scenario version
1
Published

Grading runs locally: 7 state checks read your machine when you submit; the scenario passes when every check passes. Hints, the reference solution and the check definitions are available only inside the CLI, not on this page.

Install the CLICreate a free account

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Independent community project, not affiliated with or endorsed by CNCF or The Linux Foundation. Lab results are practice feedback, not an exam score.