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Administering a Linux server

From a first SSH connection to a machine you can monitor, back up and repair.

13 courses · about 2146 minutes

This path assumes you have never administered a server. It starts with connecting and the shell, then adds, in order, what makes a machine sustainable: services, accounts, scripts, the firewall, monitoring, backups, and finally the method to apply when something breaks.

What you will be able to do

  • Connect to a server and find your way around it with no graphical interface
  • Install, start and troubleshoot a service with systemd
  • Create accounts and grant exactly the rights they need
  • Close the access nobody uses, and watch what the machine exposes
  • Restore a backup, and know what it does not contain
  • Diagnose a failure from what the machine has already told you

The path

  1. Your first server

    What a server is, how to connect to one for the first time, and how to keep it updated without breaking it.

    7 lessons · about 136 minutes

  2. Linux Fundamentals

    First steps in a Linux terminal: finding your way around the filesystem, reading files, and understanding permissions.

    11 lessons · about 193 minutes

  3. How a network works: packets, addresses and neighbours

    What actually travels between two machines, and how each one decides whether the destination is a neighbour or somebody else's problem.

    6 lessons · about 126 minutes

  4. Ports, TCP and UDP: how two programs talk

    An address names a machine, a port names a program — and a connection is nothing more than two kernels agreeing.

    5 lessons · about 104 minutes

  5. Configuring the network: an address that survives a reboot

    Assigning what the earlier courses taught you to read: addresses, routes, MTU, bridges, bonds and translation rules — and making them persist.

    11 lessons · about 222 minutes

  6. Managing services with systemd

    Start, stop and diagnose services on an Ubuntu server, and write a unit for your own application.

    9 lessons · about 168 minutes

  7. Users, sudo and SSH access

    Create accounts, grant privileges with sudo, and secure SSH with keys — without ever locking yourself out.

    10 lessons · about 217 minutes

  8. Bash scripting for administrators

    Automate administrative tasks without writing a script that fails silently or destroys data through an empty variable.

    6 lessons · about 144 minutes

  9. Firewall and hardening

    Close what has no business being open, slow automated attacks down, and check regularly what the server exposes — without locking yourself out.

    9 lessons · about 220 minutes

  10. Monitoring a server

    Read disk, memory and load correctly, control log growth, and find out before your users do.

    7 lessons · about 168 minutes

  11. Backups and restores

    Back up a database and files, apply retention, and above all verify that a restore works before you need it.

    6 lessons · about 149 minutes

  12. Diagnosing a failure: what each output proves

    Read what each output actually proves, narrow an unknown failure down to one component, and fix it without destroying the evidence that explained it.

    8 lessons · about 172 minutes

  13. Ansible for one server: a description you can run

    Optional

    Describe the machine's state in a playbook, run it until changed=0, and know what a green run does and does not prove.

    6 lessons · about 127 minutes