Chaincode Builder for Kubernetes RFC

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+---
+layout: default
+title: Chaincode Builder for Kubernetes
+nav_order: 3
+---
+
+- Feature Name: Chaincode Builder for Kubernetes
+- Start Date: 2022-12-16
+- RFC PR: (leave this empty)
+- Fabric Component: fabric-builder-k8s
+- Fabric Issue: (leave this empty)
+
+# Summary
+[summary]: #summary
+
+Promote the [Fabric Chaincode Builder for Kubernetes Hyperledger Labs project](https://github.com/hyperledger-labs/fabric-builder-k8s) to a Fabric subproject.
+
+# Motivation
+[motivation]: #motivation
+
+The experimental Fabric Chaincode Builder for Kubernetes project has been well received, forming part of the successful [full stack asset transfer workshop](https://github.com/hyperledger/fabric-samples/tree/main/full-stack-asset-transfer-guide) presented at the Hyperledger Global Forum in Dublin, and the next step is for it to graduate to an official Fabric subproject.
+
+# Guide-level explanation
+[guide-level-explanation]: #guide-level-explanation
+
+Starting with Fabric 2.0, [External Builders and Launchers](https://hyperledger-fabric.readthedocs.io/en/latest/cc_launcher.html) enable the peer to be extended with programs that can build, launch, and discover chaincode.
+The Chaincode Builder for Kubernetes enables peers to launch containerized chaincode using Kubernetes.
+
+Advantages:
+
+- prepublished chaincode images avoids compile issues at deploy time
+- standard CI/CD pipelines can be used to publish containerized chaincode images
+- chaincode traceability using [immutable image digests](https://docs.docker.com/engine/reference/commandline/pull/#pull-an-image-by-digest-immutable-identifier)
+
+# Reference-level explanation
+[reference-level-explanation]: #reference-level-explanation
+
+This is an existing [Hyperledger Labs project](https://github.com/hyperledger-labs/fabric-builder-k8s) which works with Fabric's [External Builders and Launchers](https://hyperledger-fabric.readthedocs.io/en/latest/cc_launcher.html) feature.
+
+# Drawbacks
+[drawbacks]: #drawbacks
+
+Adding another Fabric subproject increases the overall maintenance effort required for Hyperledger Fabric, however `fabric-builder-k8s` is a small self-contained repository so the impact should be minimal.
+
+# Rationale and alternatives
+[alternatives]: #alternatives
+
+The existing built-in chaincode types have significant issues with reliability and repeatability, since they actually build the chaincode source code at deploy time.
+They also do not work well in a cloud environment due to the requirement for Docker in Docker.
+
+There are other external builders and launchers:
+
+- The Chaincode as an External Service builder which was recently added to the main Fabric repository.  
+This is a good option for debugging chaincode at development time however it breaks the chaincode lifecycle since you end up approving _where_ the chaincode is running, not _what_ is running.
+- Various third party builders, some of which are open source.  
+These tend to follow the same pattern as the built-in chaincode types, with similar disadvantages.
+
+# Prior art
+[prior-art]: #prior-art
+
+[Original Hyperledger Labs project proposal](https://labs.hyperledger.org/labs/fabric-builder-k8s.html)
+
+# Testing
+[testing]: #testing
+
+An end to end test will require a Kubernetes environment and should focus on how the builder behaves when Kubernetes pods already exist, or are stopped unexpectedly.
+
+# Dependencies
+[dependencies]: #dependencies
+
+The Fabric [External Builders and Launchers](https://hyperledger-fabric.readthedocs.io/en/latest/cc_launcher.html) feature.
+
+# Unresolved questions
+[unresolved]: #unresolved-questions
+
+The core implementation is already complete, however there is scope for informing changes to the current Fabric [External Builders and Launchers](https://hyperledger-fabric.readthedocs.io/en/latest/cc_launcher.html) implementation in the future which might improve the integration with Kubernetes, for example to allow the Chaincode Builder for Kubernetes to start chaincode as an external service.