Advanced Topics

Kernel Compilation

Why Compile Kernel?

• Custom features
• Performance optimization
• Latest features/patches
• Remove unnecessary modules

Steps

1. Get kernel source: bash sudo apt install linux-source tar -xvf /usr/src/linux-source-*.tar.xz cd linux-source-*/

2. Configure: bash make menuconfig # Or xconfig, gconfig

3. Compile: bash make -j$(nproc) # Use all CPU cores sudo make modules_install sudo make install sudo update-grub

4. Reboot into new kernel.

LVM (Logical Volume Management)

Benefits

• Resize volumes without downtime
• Snapshots
• Striping/mirroring

Setup

sudo apt install lvm2
sudo pvcreate /dev/sdb
sudo vgcreate myvg /dev/sdb
sudo lvcreate -L 10G -n mylv myvg
sudo mkfs.ext4 /dev/myvg/mylv

Management

sudo lvextend -L +5G /dev/myvg/mylv  # Extend
sudo resize2fs /dev/myvg/mylv        # Resize filesystem
sudo lvcreate -L 1G -s -n mysnap myvg/mylv  # Snapshot

RAID

Software RAID

sudo apt install mdadm
sudo mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb /dev/sdc
sudo mkfs.ext4 /dev/md0

RAID Levels

• RAID 0: Striping (performance)
• RAID 1: Mirroring (redundancy)
• RAID 5: Distributed parity
• RAID 10: Striped mirrors

Containers

Docker

sudo apt install docker.io
sudo systemctl start docker
sudo usermod -aG docker $USER

Basic usage: bash docker run hello-world docker build -t myimage . docker run -d -p 80:80 myimage

LXC/LXD

sudo apt install lxd
sudo lxd init
lxc launch ubuntu:18.04 mycontainer
lxc exec mycontainer -- bash

Virtualization

KVM

sudo apt install qemu-kvm libvirt-daemon-system
sudo adduser $USER libvirt
sudo systemctl start libvirtd

VirtualBox

sudo apt install virtualbox

Systemd Advanced Features

Timers

Replace cron jobs: bash sudo systemctl edit --force --full mytimer.timer

Example timer:

[Unit]
Description=Run my script daily

[Timer]
OnCalendar=daily
Persistent=true

[Install]
WantedBy=timers.target

Services

Create custom services in /etc/systemd/system/:

[Unit]
Description=My Service

[Service]
ExecStart=/path/to/script
Restart=always

[Install]
WantedBy=multi-user.target

Security

SELinux/AppArmor

sudo apt install apparmor
sudo apparmor_status

Intrusion Detection

sudo apt install rkhunter chkrootkit
sudo rkhunter --check

VPN

sudo apt install openvpn

Certificate Management

sudo apt install certbot
certbot certonly --webroot -w /var/www/html -d example.com

Performance Monitoring

sysstat

sudo apt install sysstat
sar -u 1 5  # CPU usage
iostat -x 1  # I/O stats

Prometheus + Grafana

For advanced monitoring.

Automation

Ansible

sudo apt install ansible

Playbook example:

---
- hosts: servers
  tasks:
  - name: Update packages
    apt:
      update_cache: yes
      upgrade: yes

Puppet/Chef

Configuration management tools.

Cloud Integration

AWS CLI

sudo apt install awscli
aws configure

Google Cloud SDK

sudo apt install google-cloud-sdk

Troubleshooting Advanced Issues

Kernel Panics

Check /var/log/kern.log, update kernel, check hardware.

Boot Issues

Use recovery mode, check /boot/grub/grub.cfg.

Network Issues

Use tcpdump, wireshark, check routing.

Performance Issues

Use perf, strace, check system calls.

Practice Exercises

1. Set up a simple RAID 1 array.
2. Create a systemd timer for automated tasks.
3. Install and run a Docker container.
4. Configure a basic firewall with advanced rules.
5. Set up SSH with key-based authentication and disable password login.

Conclusion

This concludes our Linux tutorial series. You've learned from basic installation to advanced system administration. Remember:

• Practice regularly
• Read documentation (man pages, official docs)
• Join Linux communities (forums, IRC, Reddit)
• Stay updated with security patches
• Experiment in virtual machines before production

Happy Linux-ing!