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How to Install Redis In-Memory Database on Ubuntu 26.04

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Introduction

Redis is an open-source, in-memory data structure store that functions as a database, cache, and message broker. Unlike traditional databases that store data on disk, Redis keeps data in memory, enabling sub-millisecond response times for read and write operations. The database supports various data structures including strings, hashes, lists, sets, sorted sets with range queries, bitmaps, hyperloglogs, geospatial indexes, and streams. Redis powers real-time applications like session management, leaderboards, rate limiting, job queues, and full-page caching for high-traffic web services.

This guide shows you how to install Redis on Ubuntu 26.04.

Prerequisites

Before you start:

Install Redis from Ubuntu Repository

The Redis package is available by default on the Ubuntu repositories. Installing from the official repository provides a stable version tested for Ubuntu compatibility.

  • Refresh your system's package list to ensure you get the latest available versions.

    console
    $ sudo apt update

  • Install the Redis server package.

    console
    $ sudo apt install -y redis-server

    Output:

    Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
libjemalloc2 redis-tools
Suggested packages:
ruby-redis
The following NEW packages will be installed:
libjemalloc2 redis-server redis-tools
0 upgraded, 3 newly installed, 0 to remove and 0 not upgraded.
Need to get 1,234 kB of archives.
After this operation, 8.45 MB of additional disk space will be used.

  • Verify the Redis version.

    console
    $ redis-server --version

    Output:

    Redis server v=8.0.5 ...

Manage Redis Service

Redis runs as a system service on Ubuntu under the name redis-server. You can manage this service using specific commands to start, stop, restart, and check the Redis status. These commands ensure your Redis installation runs smoothly and make maintenance easier on your system.

Check Redis Service Status

console
$ sudo systemctl status redis-server

Output:

● redis-server.service - Advanced key-value store
     Loaded: loaded (/usr/lib/systemd/system/redis-server.service; enabled; preset: enabled)
     Active: active (running) since Thu 2026-03-12 14:22:10 UTC; 1min 5s ago
       Docs: http://redis.io/documentation,
             man:redis-server(1)
   Main PID: 12456 (redis-server)
     Status: "Ready to accept connections"
      Tasks: 5 (limit: 2271)
     Memory: 8.9M (peak: 9.2M)
        CPU: 234ms
     CGroup: /system.slice/redis-server.service
             └─12456 "/usr/bin/redis-server *:6379"

Press Ctrl + C.

Enable Redis to Start on Boot

console
$ sudo systemctl enable redis-server

Output:

Synchronizing state of redis-server.service with SysV service script with /usr/lib/systemd/systemd-sysv-install.
Executing: /usr/lib/systemd/systemd-sysv-install enable redis-server

Start Redis Service

console
$ sudo systemctl start redis-server

Stop Redis Service

console
$ sudo systemctl stop redis-server

Restart Redis Service

console
$ sudo systemctl restart redis-server

Test Redis Locally

Before configuring remote access, test that Redis works correctly on your local server. The redis-cli command-line tool connects to Redis and executes commands.

  • Connect to Redis using the command-line interface.

    console
    $ redis-cli

    Output:

    127.0.0.1:6379>

  • Send the ping command to test Redis.

    127.0.0.1:6379> ping

    Output:

    PONG

  • Set a test_key and set the value to Hello Redis.

    127.0.0.1:6379> set test_key "Hello Redis"

    Output:

    OK

  • Retrieve the value.

    127.0.0.1:6379> get test_key

    Output:

    "Hello Redis"

  • List all keys in the database.

    127.0.0.1:6379> keys *

    Output:

    1) "test_key"

  • Exit the Redis CLI.

    127.0.0.1:6379> exit

    Output:

    $

Configure Redis with Password Authentication

By default, Redis does not require a password for connections. Securing Redis with a password prevents unauthorized access from remote clients.

  • Open the Redis configuration file with Nano.

    console
    $ sudo nano /etc/redis/redis.conf

  • Locate the requirepass directive.

    INI
    # requirepass foobared

  • Uncomment the line and change the password to a strong value.

    INI
    requirepass your_strong_password

  • Save and close the /etc/redis/redis.conf file by pressing Ctrl + X +, Y then Enter.

  • Restart Redis to apply the password change.

    console
    $ sudo systemctl restart redis-server

  • Test the password authentication.

    console
    $ redis-cli

    Output:

    127.0.0.1:6379>

  • Try to run a command without authenticating.

    127.0.0.1:6379> get test_key

    Output:

    (error) NOAUTH Authentication required.

  • Authenticate with the password.

    127.0.0.1:6379> AUTH your_password

    Output:

    OK

  • Retrieve the value again.

    127.0.0.1:6379> get test_key

    Output:

    "Hello Redis"

  • Exit the Redis CLI.

    127.0.0.1:6379> exit

Configure Redis Memory Management

Redis stores all data in memory, so you should configure maximum memory limits and eviction policies to prevent out-of-memory crashes.

  • Open the Redis configuration file for editing.

    console
    $ sudo nano /etc/redis/redis.conf

  • Locate the maxmemory directive.

    INI
    # maxmemory <bytes>

  • Set maximum memory to 256MB for a small server.

    INI
    maxmemory 256mb

  • Locate the maxmemory-policy directive.

    INI
    # maxmemory-policy noeviction

  • Change the eviction policy to allkeys-lru which removes least recently used keys when memory fills up.

    INI
    maxmemory-policy allkeys-lru

  • Save and close the /etc/redis/redis.conf file by pressing Ctrl + X + Y.

  • Restart Redis to apply memory settings.

    console
    $ sudo systemctl restart redis-server

Monitor Redis Performance

Redis provides built-in commands to monitor performance metrics, connected clients, and memory usage.

  • Connect to Redis locally.

    console
    $ redis-cli -a your_password

  • Check Redis statistics.

    127.0.0.1:6379> INFO stats

    Output:

    # Stats
total_connections_received:5
total_commands_processed:12
instantaneous_ops_per_sec:0
total_net_input_bytes:456
total_net_output_bytes:1234
rejected_connections:0

  • Check memory usage.

    127.0.0.1:6379> INFO memory

    Output:

    # Memory
used_memory:8923456
used_memory_human:8.51M
used_memory_rss:12345678
used_memory_peak:9234567
used_memory_peak_human:8.81M
maxmemory:268435456
maxmemory_human:256.00M
maxmemory_policy:allkeys-lru
mem_fragmentation_ratio:1.38

  • Check connected clients.

    127.0.0.1:6379> INFO clients

    Output:

    # Clients
connected_clients:2
client_recent_max_input_buffer:2048
client_recent_max_output_buffer:0
blocked_clients:0
tracking_clients:0

  • Exit the Redis CLI.

    127.0.0.1:6379> exit

Conclusion

In this guide, you have installed Redis on Ubuntu 26.04 using apt, secured the database with password authentication, configured remote access, opened the firewall port, and managed memory limits with eviction policies. You also tested local and remote connections, monitored performance metrics, and verified data persistence across service restarts. Now that you have Redis running, consider integrating it with web frameworks like Django or Node.js for session storage, use it as a cache layer in front of PostgreSQL or MySQL, or implement real-time features like leaderboards and message queues using Redis data structures.

  • Database
  • NoSQL