Having load balancer before Akka Http multiple applications

0
votes

I have multiple identical Scala Akka-HTTP applications, each one is installed on a dedicated server (around 10 apps), responding to HTTP requests on port 80. in front of this setup I am using single HAproxy instance that receives all the incoming traffic and balances the workload to these 10 servers.

We would like to change the HAproxy (we suspect that it causes us latency problems) and to use a different load balancer. the requirement is to adopt a different 3rd party load balancer or to develop a simple one using scala that round robin each http request to the backend akka http apps and to proxy back the response.

  1. Is there another recommended load balancer (open source) that I can use to load balance / proxy the http incoming requests to the multiple apps other than HAproxy (maybe APACHE httpd) ?

  2. Does it make sense to write a simple akka http application route as the loadbalancer, register the backend apps hosts in some configuration file, and to roundrobin the requests to them?

  3. maybe I should consider Akka cluster to that purpose ? the thing is, that the applications are already standalone akka http services with no cluster support. and maybe it would be too much to go for clustering. (would like to keep it simple)

What is the best practice to load balance requests to http apps (especially akka http scala apps) as I might be missing something here?

Note - having back pressure is something that we also would like to have, meaning that if the servers are busy, we would like to response with 204 or some status code so our clients wont have timeouts in case my back end is busy.

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akkaload-balancingakka-streamakka-http

1 Answers

0
votes

Although Akka HTTP performance is quite impressive, I would not use it for writing a simple reverse proxy since there are tons of others out there in the community.

I am not sure where you deploy your app, but, the best (and more secure) approach is to use a LB provided by your cloud provider. Most of them has one and usually it has a good benefit-cost.

If your cloud provider does not provide one or you are hosting yourself your app, then first you should take a look on your HAProxy. Did you run tests on HAProxy in an isolated way to see it still has the same latency issues? Are you sure the config optimised for what you want? Does your HAProxy has enough resources (cpu and memory) to operate? Is your HAProxy in the same DataCenter as your deployed app?

If you follow and check all of these questions and still are having latency issues, then I would recommend you to choose another one. There are tons out there, such as Envoy and NGINX. I really like Envoy and I've been using it at work for a few months now without any complains.

Hope I could help.

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