Redis is an in-memory key-value store which NetBox employs for caching and queuing. This section entails the installation and configuration of a local Redis instance. If you already have a Redis service in place, skip to the next section.
!!! note
NetBox v2.9.0 and later require Redis v4.0 or higher. If your distribution does not offer a recent enough release, you will need to build Redis from source. Please see [the Redis installation documentation](https://github.com/redis/redis) for further details.
=== "Ubuntu"
```no-highlight
sudo apt install -y redis-server
```
=== "CentOS"
```no-highlight
sudo yum install -y redis
sudo systemctl start redis
sudo systemctl enable redis
```
You may wish to modify the Redis configuration at /etc/redis.conf or /etc/redis/redis.conf, however in most cases the default configuration is sufficient.
Use the redis-cli utility to ensure the Redis service is functional:
$ redis-cli ping
PONG