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Ubuntu Server Management

Introduction​

Ubuntu Server is a popular Linux distribution optimized for server environments. Learning to manage an Ubuntu Server is a valuable skill for system administrators, DevOps engineers, and developers who need to deploy and maintain applications in production environments.

This guide walks you through the essential aspects of Ubuntu Server management, from initial setup to everyday administrative tasks. By the end of this tutorial, you'll have a solid foundation in Ubuntu Server administration and be ready to manage your own servers with confidence.

Getting Started with Ubuntu Server​

Installing Ubuntu Server​

Before managing an Ubuntu Server, you need to install it. The installation process is straightforward:

  1. Download the latest Ubuntu Server ISO from the official Ubuntu website
  2. Create a bootable USB drive or DVD
  3. Boot your server from the installation media
  4. Follow the installation wizard

The Ubuntu Server installer provides a text-based interface that guides you through the installation process.

# After booting from installation media, you'll see a menu like this:
# Ubuntu Server 22.04 LTS
# Install
# OEM installation (for manufacturers)
# Check disc for defects
# Test memory
# Boot from first hard disk
# ...

Select "Install" and follow the prompts to configure your language, keyboard layout, network connections, and disk partitioning.

Initial System Configuration​

After installation, connect to your server using SSH:

ssh username@server_ip_address

For example:

ssh [email protected]

Once logged in, it's good practice to update your system:

sudo apt update
sudo apt upgrade

Output:

Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Calculating upgrade... Done
The following packages will be upgraded:
  ... (list of packages) ...
Do you want to continue? [Y/n] y

User Management​

Creating and Managing Users​

Ubuntu Server user management is crucial for security and access control.

Adding a New User​

sudo adduser newusername

Output:

Adding user `newusername' ...
Adding new group `newusername' (1001) ...
Adding new user `newusername' (1001) with group `newusername' ...
Creating home directory `/home/newusername' ...
Copying files from `/etc/skel' ...
New password: 
Retype new password: 
passwd: password updated successfully
Changing the user information for newusername
Enter the new value, or press ENTER for the default
	Full Name []: New User
	Room Number []: 
	Work Phone []: 
	Home Phone []: 
	Other []: 
Is the information correct? [Y/n] Y

Granting Administrative Privileges​

To allow a user to execute commands with root privileges:

sudo usermod -aG sudo username

Removing a User​

sudo deluser username

To also remove the user's home directory:

sudo deluser --remove-home username

SSH Key Authentication​

Using SSH keys is more secure than password authentication.

Generating SSH Keys on Your Local Machine​

ssh-keygen -t ed25519 -C "[email protected]"

Copying the Public Key to Your Server​

ssh-copy-id username@server_ip_address

Alternatively, you can manually add the public key:

cat ~/.ssh/id_ed25519.pub | ssh username@server_ip_address "mkdir -p ~/.ssh && cat >> ~/.ssh/authorized_keys"

Disabling Password Authentication​

Edit the SSH configuration file:

sudo nano /etc/ssh/sshd_config

Find and modify these lines:

PasswordAuthentication no
ChallengeResponseAuthentication no

Restart the SSH service:

sudo systemctl restart sshd

Package Management​

Ubuntu uses the APT (Advanced Package Tool) for managing software packages.

Installing Software​

To install a package:

sudo apt install package_name

For example, to install the NGINX web server:

sudo apt install nginx

Removing Software​

To remove a package:

sudo apt remove package_name

To remove a package and its configuration files:

sudo apt purge package_name

Updating the System​

To update the package list:

sudo apt update

To upgrade all packages:

sudo apt upgrade

To upgrade to a new Ubuntu release:

sudo do-release-upgrade

Finding Packages​

To search for packages:

apt search search_term

For example:

apt search python3

Output:

Sorting... Done
Full Text Search... Done
python3/jammy,now 3.10.6-1~22.04 amd64 [installed]
  interactive high-level object-oriented language (default python3 version)
python3-all/jammy 3.10.6-1~22.04 amd64
  package depending on all supported Python 3 runtime versions
...

Repository Management​

Add a repository:

sudo add-apt-repository ppa:repository_name/ppa

Remove a repository:

sudo add-apt-repository --remove ppa:repository_name/ppa

Service Management with Systemd​

Ubuntu Server uses systemd to manage system services.

Checking Service Status​

sudo systemctl status service_name

Example with NGINX:

sudo systemctl status nginx

Output:

● nginx.service - A high performance web server and a reverse proxy server
     Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
     Active: active (running) since Mon 2023-05-01 12:34:56 UTC; 2h 15min ago
       Docs: man:nginx(8)
   Main PID: 1234 (nginx)
      Tasks: 3 (limit: 4915)
     Memory: 3.6M
        CPU: 250ms
     CGroup: /system.slice/nginx.service
             ├─1234 "nginx: master process /usr/sbin/nginx -g daemon on; master_process on;"
             ├─1235 "nginx: worker process" "" "" "" "" "" "" "" "" "" "" "" "" "" "" "" "" "" ""
             └─1236 "nginx: worker process" "" "" "" "" "" "" "" "" "" "" "" "" "" "" "" "" "" ""

Starting, Stopping, and Restarting Services​

Start a service:

sudo systemctl start service_name

Stop a service:

sudo systemctl stop service_name

Restart a service:

sudo systemctl restart service_name

Reload service configuration without stopping:

sudo systemctl reload service_name

Enabling and Disabling Services​

Enable a service to start at boot:

sudo systemctl enable service_name

Disable a service from starting at boot:

sudo systemctl disable service_name

Creating Custom Services​

You can create custom systemd services by creating .service files in /etc/systemd/system/:

sudo nano /etc/systemd/system/myapp.service

Example service file:

[Unit]
Description=My Custom Application
After=network.target

[Service]
User=myapp
WorkingDirectory=/opt/myapp
ExecStart=/usr/bin/node /opt/myapp/server.js
Restart=on-failure

[Install]
WantedBy=multi-user.target

After creating the service file:

sudo systemctl daemon-reload
sudo systemctl enable myapp
sudo systemctl start myapp

File System Management​

Ubuntu Server's file system hierarchy follows the Linux Filesystem Hierarchy Standard.

Key directories include:

  • /etc: System configuration files
  • /var: Variable data like logs
  • /home: User home directories
  • /opt: Optional software
  • /usr: User binaries and read-only data
  • /srv: Service data

File Permissions​

List files with detailed permissions:

ls -l

Output:

total 16
drwxr-xr-x 2 user user 4096 May  1 10:00 directory
-rw-r--r-- 1 user user  123 May  1 10:01 file.txt

Change file ownership:

sudo chown user:group filename

Change file permissions:

chmod 755 filename

Permission breakdown:

  • r (read): 4
  • w (write): 2
  • x (execute): 1

Common permission patterns:

  • 755 (rwxr-xr-x): Owner can read/write/execute, others can read/execute
  • 644 (rw-r--r--): Owner can read/write, others can only read
  • 700 (rwx------): Owner can read/write/execute, others have no access

Disk Management​

Check disk space:

df -h

Output:

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1        98G   12G   82G  13% /
tmpfs           2.0G     0  2.0G   0% /dev/shm
/dev/sda2       457G  199G  235G  46% /home

Check directory sizes:

du -sh /path/to/directory

Mount a file system:

sudo mount /dev/device /mount/point

Unmount a file system:

sudo umount /mount/point

Network Configuration​

Basic Network Information​

Display network interfaces:

ip a

Output:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:b0:12:34 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.100/24 brd 192.168.1.255 scope global dynamic ens33
       valid_lft 86390sec preferred_lft 86390sec
    inet6 fe80::20c:29ff:feb0:1234/64 scope link 
       valid_lft forever preferred_lft forever

Check network connectivity:

ping -c 4 google.com

Configuring Network Interfaces​

In Ubuntu Server, network interfaces are configured using Netplan. Configuration files are located in /etc/netplan/.

Example configuration file (/etc/netplan/00-installer-config.yaml):

network:
  version: 2
  ethernets:
    ens33:
      dhcp4: no
      addresses:
        - 192.168.1.100/24
      gateway4: 192.168.1.1
      nameservers:
          addresses: [8.8.8.8, 8.8.4.4]

Apply configuration:

sudo netplan apply

Firewall Configuration with UFW​

Ubuntu Server comes with UFW (Uncomplicated Firewall), which simplifies firewall management.

Enable UFW:

sudo ufw enable

Allow SSH connections:

sudo ufw allow ssh

Allow specific ports:

sudo ufw allow 80/tcp  # HTTP
sudo ufw allow 443/tcp  # HTTPS

Check status:

sudo ufw status

Output:

Status: active

To                         Action      From
--                         ------      ----
22/tcp                     ALLOW       Anywhere
80/tcp                     ALLOW       Anywhere
443/tcp                    ALLOW       Anywhere
22/tcp (v6)                ALLOW       Anywhere (v6)
80/tcp (v6)                ALLOW       Anywhere (v6)
443/tcp (v6)               ALLOW       Anywhere (v6)

Monitoring and Logging​

System Monitoring​

Check system resources:

top

Alternative resource monitoring with htop (install if needed):

sudo apt install htop
htop

Check running processes:

ps aux

Monitor disk I/O:

iostat

Log Management​

Most system logs are stored in the /var/log directory.

View system logs:

less /var/log/syslog

Monitor logs in real-time:

tail -f /var/log/syslog

Search logs:

grep "error" /var/log/syslog

Logrotate​

Ubuntu uses logrotate to manage log files. Configuration is in /etc/logrotate.d/.

Example configuration for a custom application:

/var/log/myapp/*.log {
    daily
    missingok
    rotate 7
    compress
    delaycompress
    notifempty
    create 0640 myapp myapp
    sharedscripts
    postrotate
        systemctl reload myapp
    endscript
}

Backup and Recovery​

Creating System Backups​

Using rsync for backups:

rsync -avz --delete /source/directory/ /backup/directory/

Backing up to a remote server:

rsync -avz -e ssh /source/directory/ user@remote_server:/backup/directory/

Automating Backups with Cron​

Edit the crontab:

crontab -e

Add a schedule for daily backups at 2 AM:

0 2 * * * rsync -avz --delete /source/directory/ /backup/directory/ >> /var/log/backup.log 2>&1

System Snapshots with LVM​

If using LVM, you can create logical volume snapshots:

sudo lvcreate -L 5G -s -n snap_root /dev/vg0/root

Mount the snapshot for access:

sudo mkdir /mnt/snapshot
sudo mount /dev/vg0/snap_root /mnt/snapshot

Remove the snapshot after use:

sudo umount /mnt/snapshot
sudo lvremove /dev/vg0/snap_root

Server Security​

Security Updates​

Keep your system updated:

sudo apt update && sudo apt upgrade

Enable automatic security updates:

sudo apt install unattended-upgrades
sudo dpkg-reconfigure -plow unattended-upgrades

Securing SSH​

Edit the SSH configuration:

sudo nano /etc/ssh/sshd_config

Recommended settings:

# Disable root login
PermitRootLogin no

# Use SSH key authentication only
PasswordAuthentication no

# Set maximum authentication attempts
MaxAuthTries 3

# Change default SSH port (optional)
Port 2222

Restart SSH after changes:

sudo systemctl restart sshd

Fail2Ban for Intrusion Prevention​

Install Fail2Ban:

sudo apt install fail2ban

Create a custom jail configuration:

sudo nano /etc/fail2ban/jail.local

Example configuration:

[sshd]
enabled = true
port = ssh
filter = sshd
logpath = /var/log/auth.log
maxretry = 3
bantime = 3600

Start Fail2Ban:

sudo systemctl enable fail2ban
sudo systemctl start fail2ban

Check Fail2Ban status:

sudo fail2ban-client status sshd

Advanced Server Management​

Automating Tasks with Bash Scripts​

Create a bash script:

nano backup_script.sh

Script content:

#!/bin/bash

# Backup important directories
BACKUP_DIR="/backup"
DATE=$(date +%Y-%m-%d)
mkdir -p "$BACKUP_DIR/$DATE"

# Backup config files
tar -czf "$BACKUP_DIR/$DATE/etc_backup.tar.gz" /etc

# Backup databases
mysqldump -u root -p --all-databases > "$BACKUP_DIR/$DATE/all_databases.sql"

# Log success
echo "Backup completed on $DATE" >> "$BACKUP_DIR/backup.log"

Make the script executable:

chmod +x backup_script.sh

Setting Up a LAMP Stack​

Install Apache, MySQL, and PHP:

sudo apt install apache2 mysql-server php libapache2-mod-php php-mysql

Secure MySQL installation:

sudo mysql_secure_installation

Create a PHP test file:

echo "<?php phpinfo(); ?>" | sudo tee /var/www/html/info.php

Containerization with Docker​

Install Docker:

sudo apt install docker.io

Start and enable Docker:

sudo systemctl start docker
sudo systemctl enable docker

Add your user to the Docker group:

sudo usermod -aG docker $USER

Test Docker installation:

docker run hello-world

System Architecture Diagram​

Here's a high-level overview of Ubuntu Server architecture:

Summary​

In this guide, we've covered the essential aspects of Ubuntu Server management:

  1. Installation and initial configuration
  2. User management and SSH key authentication
  3. Package management with APT
  4. Service management with systemd
  5. File system management and permissions
  6. Network configuration and firewall setup
  7. Monitoring and logging
  8. Backup and recovery strategies
  9. Server security best practices
  10. Advanced management techniques

By mastering these fundamentals, you're well on your way to becoming proficient in Ubuntu Server administration. Remember that server management is both an art and a science—while following best practices is important, experience and problem-solving skills are equally valuable.

Additional Resources​

Here are some resources to continue your Ubuntu Server learning journey:

  • Documentation: The official Ubuntu Server documentation
  • Practice: Set up a virtual machine for experimenting without risk
  • Community: Join the Ubuntu community forums for help and discussion

Exercises​

  1. Basic Setup: Install Ubuntu Server on a virtual machine and secure SSH access.
  2. Web Server: Configure a web server with NGINX or Apache and deploy a simple website.
  3. Database: Set up MySQL or PostgreSQL and create a database with tables.
  4. Automation: Write a bash script to automate a daily backup of important files.
  5. Security: Configure UFW to allow only necessary services and set up Fail2Ban.
  6. Monitoring: Install and configure a monitoring tool like Prometheus or Grafana.
  7. High Availability: Research and implement a high-availability solution for a web application.

If you spot any mistakes on this website, please let me know at [email protected]. I’d greatly appreciate your feedback! :)