Purpose

This article provides guidance on how to install and configure a basic Redis instance for use in a Small-Scale Hipchat Data Center environment.

In this guide, we will install Redis 3.2 on a CentOS 7 Linux server.

Before you begin, we recommend that you familiarize yourself with installing and configuring CentOS 7 using the Linux command line. 

Prepare

• Make sure the system on which Redis will be installed meets the Hardware Requirements for the Data Stores Node.
• Download and install CentOS 7 on the server using the minimal ISO image.

• Install the Extras Packages for Enterprise Linux (EPEL) package.  This will set up the EPEL repository for installing Redis:

  sudo yum -y install epel-release

Install and Configure

1. Install Redis from the EPEL repository.

   sudo yum -y install redis

2. Start Redis and configure it to start automatically when the server boots up.

   sudo systemctl start redis
   sudo systemctl enable redis

3. Test Redis to see if it is working.  If you receive a PONG response, it means that the server is functioning and responding to commands.

   redis-cli ping
   PONG

4. As the root user, open /etc/redis.conf in a text editor to locate and set the following values (if they are not set already).  For requirepass, use an appropriate password instead of the (too easy to guess) "hipchat" in the example below.

   appendonly no
   appendfsync everysec
   no-appendfsync-on-rewrite no
   auto-aof-rewrite-min-size 64mb
   auto-aof-rewrite-percentage 100
   stop-writes-on-bgsave-error yes
   rdbcompression yes
   maxclients 10000
   repl-timeout 60
   tcp-keepalive 60
   timeout 0
   requirepass hipchat

5. In the same file, comment out the bind line provided below. This makes Redis listen on all interfaces for external connections.

   bind 127.0.0.1

   Commenting out this setting allows Redis to listen on all available interfaces. Your organization's security policies may not allow this. Learn more about Redis security from the Redis project documentation.

6. Restart the Redis service.

   sudo systemctl restart redis

7. Open port 6379 on the CentOS server's firewall to allow external connections.

   sudo firewall-cmd --add-port=6379/tcp --permanent
   sudo firewall-cmd --reload

8. As the root user, verify that Redis is listening for connections on port 6379.  Using the examples above, the expected output would look like the following:

   ss -antlp | grep 6379
   LISTEN     0      128          *:6379                     *:*                   users:(("redis-server",pid=1015,fd=5))
   LISTEN     0      128         :::6379                    :::*                   users:(("redis-server",pid=1015,fd=4))

Continue setting up the Data Center according to the guidelines in the Configure Hipchat Data Center Nodes documentation.