Redis: Installation and Basic Usage

How to install and configure Redis on your VPS for caching, sessions and message queues

Redis is an extremely fast in-memory database used for caching, session management, message queues and much more. It's used by Laravel, WordPress (with plugins), Next.js, and many other applications.

Installation

# Debian/Ubuntu
apt update && apt install redis-server -y

# CentOS/AlmaLinux
dnf install redis -y

# Start and enable
systemctl enable --now redis

Verify installation

systemctl status redis

# Test from CLI
redis-cli ping
# Response: PONG

Basic configuration

nano /etc/redis/redis.conf

Important parameters

# Listen only on localhost (more secure, default)
bind 127.0.0.1 -::1

# Port (default 6379)
port 6379

# Access password (recommended)
requirepass long_secure_password

# Maximum memory size
maxmemory 256mb

# Policy when memory is full
# allkeys-lru: removes least recently used keys (recommended for cache)
maxmemory-policy allkeys-lru

# Persistence to disk (comment out if using Redis only as cache)
# save 900 1
# save 300 10
# save 60 10000

systemctl restart redis

Basic Redis commands

# Access CLI
redis-cli

# With password
redis-cli -a long_secure_password

# Test
PING

# Set a value
SET key "value"

# Read a value
GET key

# Set with expiration (60 seconds)
SET session:123 "data" EX 60

# Check TTL (remaining time)
TTL session:123

# Delete a key
DEL key

# List all keys (avoid in production with many keys!)
KEYS *

# Total number of keys
DBSIZE

# Server info
INFO server
INFO memory

Redis with Laravel

In .env:

CACHE_DRIVER=redis
SESSION_DRIVER=redis
QUEUE_CONNECTION=redis

REDIS_HOST=127.0.0.1
REDIS_PASSWORD=long_secure_password
REDIS_PORT=6379

Install the PHP client:

composer require predis/predis
# or install PHP extension:
apt install php-redis -y
systemctl restart php8.2-fpm

Redis with WordPress

Install the Redis Object Cache plugin:

WordPress Dashboard → Plugins → Add New → search "Redis Object Cache"
Install and activate
Add to wp-config.php:

define('WP_REDIS_HOST', '127.0.0.1');
define('WP_REDIS_PORT', 6379);
define('WP_REDIS_PASSWORD', 'long_secure_password');
define('WP_REDIS_DATABASE', 0);

Dashboard → Settings → Redis → Enable Object Cache

Monitor Redis

# Real-time statistics
redis-cli -a PASSWORD info stats

# Commands executed per second (updates every second)
redis-cli -a PASSWORD --stat

# Monitor all commands in real time (dev only, impacts performance)
redis-cli -a PASSWORD monitor

# Memory used
redis-cli -a PASSWORD info memory | grep used_memory_human

Redis must not be exposed on the internet

Redis has no advanced protections: never expose it on a public port. It must always listen on 127.0.0.1 (localhost) or on a private network.

Verify the port is not exposed:

ss -tlnp | grep 6379
# Must show 127.0.0.1:6379, NOT 0.0.0.0:6379

If for some reason it is exposed publicly, block it immediately:

ufw deny 6379

Flush the cache

# Empty the current database (DB 0)
redis-cli -a PASSWORD FLUSHDB

# Empty all databases
redis-cli -a PASSWORD FLUSHALL

Redis: Installation and Basic Usage

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