LFCS exam prep: objective-by-objective labs
You practise each LFCS objective unguided in its own Ubuntu lab and verify the result with your own commands.
Level 201 · 21 lessons · 18 practice labs
Lessons
Essential commands
- Comparing files, processing text and searching
- Archives and verified backups
- Versioning configuration files with Git
- Creating and inspecting SSL certificates
- Short task: take a daily backup of /etc and compare the changes
Operations
- Kernel parameters and modules
- Managing processes and resources
- Package and repository management
- Running virtual machines and containers
- Short task: start a containerised service at boot
Users and networking
- User environments, shell profiles and limits
- Static and multiple addresses with netplan
- Routing and NAT
- Reverse proxying and load balancing with Nginx
- Time synchronisation and SSH configuration
- Short task: put a web service with two back ends behind a reverse proxy
Storage
- Creating and growing LVM
- RAID with mdadm
- Serving and mounting an NFS share
- A shared area with quotas and ACLs
- Capstone: combine every objective in one scenario
Practice labs
- Diff two configuration files: You compare the live and backup configuration files and write the changed lines to a file in unified diff format.
- Replace an old server name across a hundred files: You replace an old server name with the new one in every configuration file of a directory tree, keep backups and count the changed files.
- Build a per-customer usage report from an access log: With awk you group an access log by customer code and produce a sorted report of request counts and total bytes.
- Put a configuration directory under Git: You initialise a repository in a service's configuration directory, exclude secret key files and make the first commit.
- Find the change that broke a service in history: You find which commit added the line that broke a service and revert only that change.
- Try a risky setting on a branch, then merge: You apply a new proxy setting on a separate branch, test the service, merge to main and tag the release.
- Read a certificate's subject and expiry: With openssl you extract a certificate file's subject, alternative names and expiry date.
- Generate a certificate request with alternative names: You generate a new key and a signing request with two alternative names and verify its contents.
- Find the certificate that doesn't match its key: You prove with modulus digests the key and certificate mismatch stopping a web server and install the right pair.
- Set up a reverse proxy to one back end: You configure Nginx as a reverse proxy to a local application and verify the original client address is passed in a header.
- Balance load across three back ends by weight: You define weights in a three-back-end upstream block and count that a hundred requests split in the expected ratio.
- Take a failed back end out of the pool automatically: With failure count and timeout settings you show a failed back end leaves the pool and re-enters traffic when it returns.
- Read a RAID array's state: From /proc/mdstat and mdadm --detail you report the array's level, members and sync state.
- Build a mirrored array from two disks: You build RAID 1 from two empty disks, create a file system and make it assemble and mount at boot via mdadm.conf and fstab.
- Replace a failed disk without losing data: You mark a disk in the array failed and remove it, add a new one and show the data stays accessible until resync finishes.
- Mount an NFS share on a client: You list a server's exports, mount one on the client and test that write permission is as expected.
- Export a share to one subnet only: You export a directory read-only to the office subnet and writable to the admin machine and test from two clients.
- Put user quotas on a shared area: You enable quotas on a shared project volume, set soft and hard limits per user and show a write over the limit is refused.
About this course
You practise each LFCS objective unguided in its own Ubuntu lab and verify the result with your own commands.
What you will learn
- Essential commands
- Operations
- Users and networking
- Storage
Prerequisites
Finishing the level 101 courses of the same path, or knowing those topics, is enough.
Lab environment
Lessons run in your own Kali Linux terminal in the browser, connected to a private lab network. Nothing to install.
Frequently asked questions
- Is this course right for my level?
- The course is at level 201; it assumes you know the topics of the lower-level courses.
- Is there anything to install?
- No. Every lesson runs in your own lab environment that opens in the browser.
- How do lessons work?
- Each lesson has 8 to 10 steps and a short quiz. Early steps show the command to type, later steps give less help; if two attempts fail, the solution opens.
- Can I try it for free?
- Yes. The first three lessons of every course are free.