Add a Node to Percona XtraDB Cluster on Debian 12

Prerequisites

• Cluster bootstrapped and running
• PXC installed on this node
• Ports 3306, 4444, 4567, 4568 open

Configure this node (/etc/mysql/mysql.conf.d/mysqld.cnf, example Node 2)

[mysqld]
server-id            = 2
wsrep_on...

Apache .htaccess and mod_rewrite on Debian 12

Enable mod_rewrite

a2enmod rewrite && systemctl restart apache2

Allow overrides in virtual host

    AllowOverride All
    Require all granted

Common .htaccess recipes

Force HTTPS

RewriteEng...

Apache + PHP-FPM on Debian 12

Step 1 – Enable proxy modules

a2enmod proxy_fcgi setenvif
a2enconf php8.2-fpm
systemctl reload apache2

Step 2 – Virtual host with PHP-FPM handler

    ServerName example.com
    DocumentRoot /var/www/example.com/html
    ...

Bootstrap a Percona XtraDB Cluster on Debian 12

Nodes: 192.168.1.10 (bootstrap) · 192.168.1.11 · 192.168.1.12

Step 1 – Configure Node 1 (/etc/mysql/mysql.conf.d/mysqld.cnf)

[mysqld]
server-id            = 1
wsrep_on             = ON
wsrep_provider       = /usr/lib64/galera4/libgalera_sm...

Configure Apache Virtual Hosts on Debian 12

Step 1 – Create document root

mkdir -p /var/www/example.com/html
echo '
Works!
' > /var/www/example.com/html/index.html
chown -R www-data:www-data /var/www/example.com 2>/dev/null || chown -R apache:apache /var/www/example.com 2>/dev/null || tru...

Configure UFW on Debian 12

Install and set defaults

apt install -y ufw
ufw default deny incoming
ufw default allow outgoing

Allow services

ufw allow ssh
ufw allow 80/tcp
ufw allow 443/tcp
ufw enable

Status

ufw status verbose

Allow from specific IP

ufw allow from 192.168.1.100 to any...

Configure Nginx as a Reverse Proxy on Debian 12

Basic reverse proxy

upstream backend {
    server 127.0.0.1:3000;
}

server {
    listen 80;
    server_name app.example.com;
    location / {
        proxy_pass         http://backend;
        proxy_http_version 1.1;
        proxy_set_header   Upg...

Configure Nginx Virtual Hosts on Debian 12

Step 1 – Create the document root

mkdir -p /var/www/example.com/html
echo '
Works!
' > /var/www/example.com/html/index.html

Step 2 – Create /etc/nginx/sites-available/example.com

server {
    listen 80;
    listen [::]:80;
    server_name ex...

Configure OpenSMTPD on Debian 12

Install

# OpenBSD – built-in:
rcctl enable smtpd && rcctl start smtpd

# Other platforms:
# Ubuntu/Debian:
apt install opensmtpd
# AlmaLinux/RHEL:
dnf install opensmtpd
# Arch:
pacman -S opensmtpd

Basic /etc/mail/smtpd.conf

pki mail.example.com cert "/etc/ss...

Elasticsearch Multi-Node Cluster on Debian 12

Nodes: node-1 192.168.1.10 · node-2 192.168.1.11 · node-3 192.168.1.12

Node 1 elasticsearch.yml

cluster.name: production-cluster
node.name: node-1
node.roles: [master, data, ingest]
network.host: 192.168.1.10
http.port: 9200
transport.port:...

Elasticsearch Snapshot Backup on Debian 12

Register filesystem repository

mkdir -p /var/backups/elasticsearch
chown elasticsearch:elasticsearch /var/backups/elasticsearch

elasticsearch.yml: path.repo: ["/var/backups/elasticsearch"]

curl -X PUT "https://localhost:9200/_snapshot/my_backup" \...

Enable TLS/SSL on Apache – Debian 12

Step 1 – Enable mod_ssl

a2enmod ssl rewrite && systemctl restart apache2

Step 2 – Generate self-signed certificate

openssl req -x509 -nodes -days 365 -newkey rsa:2048 \
    -keyout /etc/ssl/private/apache-selfsigned.key \
    -out /etc/ssl/certs/apache-se...

Enable TLS/SSL on Nginx – Debian 12

Step 1 – Self-signed certificate (testing)

openssl req -x509 -nodes -days 365 -newkey rsa:2048 \
    -keyout /etc/ssl/private/nginx-selfsigned.key \
    -out /etc/ssl/certs/nginx-selfsigned.crt \
    -subj "/CN=example.com"
openssl dhparam -out /etc/ssl/certs/...

HAProxy MySQL Load Balancing on Debian 12

Config section

listen mysql-cluster
    bind *:3306
    mode    tcp
    option  mysql-check user haproxy_check
    balance leastconn
    server db1 192.168.1.10:3306 check weight 1
    server db2 192.168.1.11:3306 check weight 1
    server db3 192.168.1....

HAProxy TLS Termination on Debian 12

Step 1 – Combine cert + key

cat /etc/ssl/certs/example.com.crt /etc/ssl/private/example.com.key > /etc/haproxy/certs/example.com.pem
chmod 600 /etc/haproxy/certs/example.com.pem
openssl dhparam -out /etc/haproxy/dhparam.pem 2048

Step 2 – Config

global...

Harden SSH on Debian 12

Back up config

cp /etc/ssh/sshd_config /etc/ssh/sshd_config.bak

Key settings (/etc/ssh/sshd_config)

Port 2222
PermitRootLogin no
PasswordAuthentication no
PubkeyAuthentication yes
AllowUsers deploy alice
Protocol 2
ClientAliveInterval 600
ClientAliveCountMax 0
X11Fo...

Install and Configure Postfix on Debian 12

Step 1 – Install

DEBIAN_FRONTEND=noninteractive apt install -y postfix
systemctl enable --now postfix

Step 2 – /etc/postfix/main.cf

myhostname  = mail.example.com
mydomain    = example.com
myorigin    = $mydomain
inet_interfaces = all
inet_protocol...

Install Apache HTTP Server on Debian 12

Step 1 – Install

apt update && apt upgrade -y
apt install -y apache2
systemctl enable --now apache2

Step 2 – Open firewall ports

ufw allow 'Apache Full'
ufw reload

Step 3 – Verify

curl -I http://localhost
apachectl -v

Main config: /etc/apache2/a...

Install Docker on Debian 12

Step 1 – Install

install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/$(. /etc/os-release && echo "$ID")/gpg | gpg --dearmor -o /etc/apt/keyrings/docker.gpg
chmod a+r /etc/apt/keyrings/docker.gpg
echo "deb [arch=$(dpkg --print-architecture...

Install Elasticsearch on Debian 12

Step 1 – Install

wget -qO - https://artifacts.elastic.co/GPG-KEY-elasticsearch | gpg --dearmor -o /usr/share/keyrings/elasticsearch-keyring.gpg
echo "deb [signed-by=/usr/share/keyrings/elasticsearch-keyring.gpg] https://artifacts.elastic.co/packages/8.x/apt sta...

Install Fail2Ban on Debian 12

Step 1 – Install

apt install -y fail2ban
systemctl enable --now fail2ban

Step 2 – /etc/fail2ban/jail.local

[DEFAULT]
bantime  = 3600
findtime = 600
maxretry = 5
banaction = iptables-multiport
ignoreip = 127.0.0.1/8 192.168.1.0/24

[sshd]
enabled  = true
port...

Install Gitea on Debian 12

Step 1 – Create git user and download binary

useradd -r -m -d /home/git -s /bin/bash git
VERSION=1.22.0
wget -O /usr/local/bin/gitea https://dl.gitea.com/gitea/${VERSION}/gitea-${VERSION}-linux-amd64
chmod +x /usr/local/bin/gitea

Step 2 – Directories

mkdir -p /var/...

Install Grafana on Debian 12

Step 1 – Install

wget -q -O - https://packages.grafana.com/gpg.key | gpg --dearmor | tee /usr/share/keyrings/grafana.gpg > /dev/null
echo "deb [signed-by=/usr/share/keyrings/grafana.gpg] https://packages.grafana.com/oss/deb stable main" | tee /etc/apt/sources.list.d/...

Install HAProxy on Debian 12

Step 1 – Install

apt update && apt upgrade -y
apt install -y haproxy
systemctl enable --now haproxy

Step 2 – Basic /etc/haproxy/haproxy.cfg

global
    log /dev/log local0
    chroot /var/lib/haproxy
    stats socket /run/haproxy/admin.sock mode 660 level admin...