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58 lines
2.0 KiB
58 lines
2.0 KiB
2 years ago
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# Add dual stack support to netpol agent
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3 years ago
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Date: 2021-12-13
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## Status
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Accepted
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## Context
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Currently the network policy agent included in k3s is in fact a copied code of
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[kube-router's](https://github.com/cloudnativelabs/kube-router) network policy
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controller, which can be found [here](https://github.com/k3s-io/k3s/tree/master/pkg/agent/netpol).
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The first and the most important issue is that kube-router lacks support for
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dual-stack (and even IPv6 in general in the most of its components). However,
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implementing such support is a non-trivial task.
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The second issue is that we include a copy of kube-router code in k3s, which
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makes it hard to consume updates. Even if we need some changes on top of
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upstream code, we should rather use a fork which is easy to rebase with
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upstream.
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## Decision
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We implement a feature of supporting dual stack Kubernetes clusters in network
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policy controller in kube-router. We start from network policy controller, as
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we don't consume any other kube-router components in k3s.
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Once it's done and working, we submit a pull request:
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* to [our fork of kube-router](https://github.com/k3s-io/kube-router)
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* [upstream](https://github.com/cloudnativelabs/kube-router)
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The motivation behind keeping a fork is that:
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* upstream might ask for implementing dual-stack in all kube-router
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components (which would be understandable)
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* acceepting a solution upstream might take long time
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Our fork of kube-router is going to be used as a vendored library inside k3s
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code. And the currently copied code in k3s in `pkg/agent/netpol` is going to
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be removed in favor of using kube-router as a library.
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As soon as dual-stack becomes an upstream feature - k3s is going to use
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upstream kube-router as a vendored library.
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## Consequences
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It will increase k3s product portfolio by fully supporting dual-stack
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networking.
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However, it might also introduce significant amount of work for developers
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which could be related to:
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* agreeing with proper solution upstream
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* maintaining a fork until that happens (rebasing with upstream releases)
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