How to Install Redis on Ubuntu 18.04 & 16.04 LTS

Redis is an in-memory data structure store, used as a database server, cache, and message broker. Redis is written in C programming language. It also provides a PHP module for communication between PHP script with the Redis server.

This tutorial will help you with the installation of Redis server along with PHP Redis PHP extensions on an Ubuntu 19.04, 18.04 LTS, 16.04 LTS and 14.04.

Step 1 – Prerequsities

Log in to your system with sudo privilege account using shell access, to which you need to install Redis.

ssh ubuntu@remote

Update the apt-get packages index files and also update existing packages to the newest versions by using the following commands:

sudo apt-get update
sudo apt-get upgrade

Step 2 – Installing Redis

The Redis packages are available under the default apt repository. For the installation of Redis on an Ubuntu VPS. Run below command from the terminal to install Redis on your machine:

sudo apt-get install redis-server

Next is to enable Redis to start on system boot. Also restart Redis service once.

sudo systemctl enable redis-server.service

Step 3 – Configure Redis

Redis can be started without a configuration file using a built-in default configuration. But to make any extra parameter changes you can use its configuration file that is: /etc/redis/redis.conf. Edit the Redis configuration file in a text editor to make changes

sudo vim /etc/redis/redis.conf

Update the following values in Redis configuration file according to your requirement. You can increase max memory limit as per available on your server.

maxmemory 256mb
maxmemory-policy allkeys-lru

The above configuration tells Redis to remove any key using the LRU algorithm when the max memory of 256mb is reached. Save the configuration file and restart the Redis service:

sudo systemctl restart redis-server.service

Step 4 – Install Redis PHP Extension

Now, if you need to use Redis from PHP application, you also need to install Redis PHP extension on your Ubuntu system. Run below command to install:

sudo apt-get install php-redis

Step 5 – Test Connection to Redis Server

Use redis-cli tool to verify the connection between the Redis server.

redis-cli

127.0.0.1:6379> ping
PONG
127.0.0.1:6379>

Few more examples of redis-cli command line tool. You can find more details about redis-cli here.

redis-cli info
redis-cli info stats
redis-cli info server