Monday, 17 July 2017

Using redis failover with F5 and Kemp load balancers

I normally use an F5 for all my load balancing needs, but recently found myself needing to use a Kemp.

Setting up an F5 is easy, just create a pool, and set up monitor like so:


Basically this detects which node is the master and sets it as the only node active. Upon a failover, there will be a short outage and a new node will be elected and come online.

The principal is the same for the Kemp LB, but unfortunately you cannot send clear text.

You need to set:

Real Server Check Method: Binary Data
Checked Port: 6379 (or whatever port you are using)
Data to Send: 696e666f0d0a717569740d0a (this is the binary equivalent of the info command)
Reply Pattern: 726f6c653a6d6173746572
Find Match Within: 0



Your redis should now be working with your Kemp
Note that this does not work with Authenticated sessions.