52 lines
1.8 KiB
Markdown
52 lines
1.8 KiB
Markdown
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---
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title: Availability zone aware routing
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authors:
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- "@ElvinEfendi"
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reviewers:
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- "@aledbf"
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approvers:
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- "@aledbf"
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editor: TBD
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creation-date: 2019-08-15
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last-updated: 2019-08-15
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status: provisional
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---
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# Availability zone aware routing
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## Table of Contents
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<!-- toc -->
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- [Summary](#summary)
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- [Motivation](#motivation)
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- [Goals](#goals)
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- [Non-Goals](#non-goals)
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<!-- /toc -->
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## Summary
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Teach ingress-nginx about availability zones where endpoints are running in. This way ingress-nginx pod will do its best to proxy to zone-local endpoint.
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## Motivation
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When users run their services across multiple availability zones they usually pay for egress traffic between zones. Providers such as GCP, AWS charges money for that.
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ingress-nginx when picking an endpoint to route request to does not consider whether the endpoint is in different zone or the same one. That means it's at least equally likely
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that it will pick an endpoint from another zone and proxy the request to it. In this situation response from the endpoint to ingress-nginx pod is considered as
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inter zone traffic and costs money.
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At the time of this writing GCP charges $0.01 per GB of inter zone egress traffic according to https://cloud.google.com/compute/network-pricing.
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According to https://datapath.io/resources/blog/what-are-aws-data-transfer-costs-and-how-to-minimize-them/ AWS also charges the same amount of money sa GCP for cross zone, egress traffic.
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This can be a lot of money depending on once's traffic. By teaching ingress-nginx about zones we can eliminate or at least decrease this cost.
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Arguably inter-zone network latency should also be better than cross zone.
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### Goals
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* Given a regional cluster running ingress-nginx, ingress-nginx should do best effort to pick zone-local endpoint when proxying
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### Non-Goals
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* -
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