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How to Boot Up Redis

1.Installing Redis on Debian

Add the repository to the APT index, update it, and install Redis:

sudo apt-get install lsb-release curl gpg
curl -fsSL https://packages.redis.io/gpg | sudo gpg --dearmor -o /usr/share/keyrings/redis-archive-keyring.gpg
sudo chmod 644 /usr/share/keyrings/redis-archive-keyring.gpg
echo "deb [signed-by=/usr/share/keyrings/redis-archive-keyring.gpg] https://packages.redis.io/deb $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/redis.list
sudo apt-get update
sudo apt-get install redis
  • Then enable and start the service:
sudo systemctl enable redis
sudo systemctl start redis

2. Basic Configuration (to Avoid Chaos)

  • Redis has a bad habit of storing everything in RAM, so if you don’t configure it properly, it could eat all your memory and crash your system. (A very unforgiving trait.)
  • Edit /etc/redis/redis.conf and set some sanity limits:
maxmemory 256mb
maxmemory-policy allkeys-lru

Explanation:

  • Limits Redis to 256MB so it doesn’t consume your entire system.
  • Uses allkeys-lru policy, meaning it will automatically remove the least recently used keys once the memory limit is reached.

3. Connecting to Redis

  • After installing, you can test it by running:
redis-cli ping

  • If it replies with PONG, congratulations—you've awakened another beast.

  • Set and retrieve a value:

SET spell "fireball"
GET spell

→ Should return "fireball" (instant, no SQL involved).

4. Securing Redis (Because It Trusts Too Much)

  • By default, Redis binds to all interfaces, meaning anyone could connect if they know the IP. That’s bad.

  • Limit Redis to localhost: Edit /etc/redis/redis.conf and change:

# bind 127.0.0.1 ::1

Keep this enabled by default

protected-mode yes
  • Set a strong password: Set a password (optional, overkill for local but useful for staging/prod):
requirepass supersecurepassword

🔐 If you do this, don't forget to connect with:

Redis.new(password: ENV['REDIS_PASSWORD'])
  • Restart Redis for changes to apply:
sudo systemctl restart redis

Confirm it's only bound to localhost:

sudo ss -tlnp | grep redis