Stop Buying Load Balancers and Start Controlling Your Traffic Flow with Software

Re:Stop Buying Load Balancers and Start Controlling Your Tra... by transitorykris on Wednesday May 28, 2014 @02:18PM (#7811897)

This can shift complexity to elsewhere in your stack. A couple points to add.

Be mindful of the specific routing hardware you're using:

Announcing and withdrawing prefixes can cause the router to select new next hops (i.e. servers). This is mostly a problem with TCP and other connection oriented protocols (or even connectionless if you're expecting a client to be sticky to a server).

You may also lose the ability to do un-equal cost load balancing.

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Re:Stop Buying Load Balancers and Start Controlling Your Tra... by yelloblac on Wednesday May 28, 2014 @03:26PM (#7812255)

I think that's an important catch, flow breaking can happen dependent on what hardware you're using and how you swap in next-hops. It definitely requires a deep understanding of how flows are hashed.

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Re:Stop Buying Load Balancers and Start Controlling Your Tra... by phil21 on Wednesday May 28, 2014 @04:49PM (#7812807)

Agreed. Also many applications for this you might just not care if a flow gets broken. Really depends on your use case.

Persistent hashing is key if you care about it though, I honestly don't know which routers do this off the top of my head :)

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