**Authors:** TimYin Shi, Dominic Yin, Wang Zhan, Jessica Jiang, Will Cai, Jeffrey Gao, Simon Sun (Inspur)
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**作者:** 石光银，尹东超，展望，江燕，蔡卫卫，高传集，孙思清（浪潮）
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## Background
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## 背景
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[MIPS](https://en.wikipedia.org/wiki/MIPS_architecture) (Microprocessor without Interlocked Pipelined Stages) is a reduced instruction set computer (RISC) instruction set architecture (ISA), appeared in 1981 and developed by MIPS Technologies. Now MIPS architecture is widely used in many electronic products.
[Kubernetes](https://kubernetes.io) has officially supported a variety of CPU architectures such as x86, arm/arm64, ppc64le, s390x. However, it's a pity that Kubernetes doesn't support MIPS. With the widespread use of cloud native technology, users under MIPS architecture also have an urgent demand for Kubernetes on MIPS.
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[Kubernetes](https://kubernetes.io) 官方目前支持众多 CPU 架构诸如 x86, arm/arm64, ppc64le, s390x 等。然而目前还不支持 MIPS 架构，始终是一个遗憾。随着云原生技术的广泛应用，MIPS 架构下的用户始终对 Kubernetes on MIPS 有着迫切的需求。
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## Achievements
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## 成果
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For many years, to enrich the ecology of the open-source community, we have been working on adjusting MIPS architecture for Kubernetes use cases. With the continuous iterative optimization and the performance improvement of the MIPS CPU, we have made some breakthrough progresses on the mips64el platform.
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多年来，为了丰富开源社区的生态，我们一直致力于在 MIPS 架构下适配 Kubernetes。随着 MIPS CPU 的不断迭代优化和性能的提升，我们在 mips64el 平台上取得了一些突破性的进展。
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Over the years, we have been actively participating in the Kubernetes community and have rich experience in the using and optimization of Kubernetes technology. Recently, we tried to adapt the MIPS architecture platform for Kubernetes and achieved a new a stage on that journey. The team has completed migration and adaptation of Kubernetes and related components, built not only a stable and highly available MIPS cluster but also completed the conformance test for Kubernetes v1.16.2.
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_Figure 1 Kubernetes on MIPS_
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_图一 Kubernetes on MIPS_
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## K8S-MIPS component build
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## K8S-MIPS 组件构建
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Almost all native cloud components related to Kubernetes do not provide a MIPS version installation package or image. The prerequisite of deploying Kubernetes on the MIPS platform is to compile and build all required components on the mips64el platform. These components include:
Thanks to the excellent design of Golang and its good support for the MIPS platform, the compilation processes of the above cloud native components are greatly simplified. First of all, we compiled Golang on the latest stable version for the mips64el platform, and then we compiled most of the above components with source code.
During the compilation processes, we inevitably encountered many platform compatibility problems, such as a Golang system call compatibility problem (syscall), typecasting of syscall. Stat_t from uint32 to uint64, patching for EpollEvent, and so on.
To build K8S-MIPS components, we used cross-compilation technology. Our process involved integrating a QEMU tool to translate MIPS CPU instructions and modifying the build script of Kubernetes and E2E image script of Kubernetes, Hyperkube, and E2E test images on MIPS architecture.
The most straightforward way to verify the stability and availability of the K8S-MIPS cluster is to run a Kubernetes [conformance test](https://github.com/kubernetes/kubernetes/blob/v1.16.2/cluster/images/conformance/README.md).
Conformance is a standalone container to launch Kubernetes end-to-end tests for conformance testing.
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一致性测试是一个独立的容器，用于启动 Kubernetes 端到端的一致性测试。
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Once the test has started, it launches several pods for various end-to-end tests. The source code of those images used by these pods is mostly from `kubernetes/test/images`, and the built images are at `gcr.io/kubernetes-e2e-test-images`. Since there are no MIPS images in the repository, we must first build all needed images to run the test.
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当执行一致性测试时，测试程序会启动许多 Pod 进行各种端到端的行为测试，这些 Pod 使用的镜像源码大部分来自于 `kubernetes/test/images` 目录下，构建的镜像位于 `gcr.io/kubernetes-e2e-test-images/`。由于镜像仓库中目前并不存在 MIPS 架构的镜像，我们要想运行 E2E 测试，必须首先构建出测试所需的全部镜像。
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### Build needed images for test
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### 构建测试所需镜像
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The first step is to find all needed images for the test. We can run `sonobuoy images-p e2e` command to list all images, or we can find those images in [/test/utils/image/manifest.go](https://github.com/kubernetes/kubernetes/blob/master/test/utils/image/manifest.go). Although Kubernetes officially has a complete Makefile and shell-script that provides commands for building test images, there are still a number of architecture-related issues that have not been resolved, such as the incompatibilities of base images and dependencies. So we cannot directly build mips64el architecture images by executing these commands.
Most test images are in golang, then compiled into binaries and built as Docker image based on the corresponding Dockerfile. These images are easy to build. But note that most images are using alpine as their base image, which does not officially support mips64el architecture for now. For this moment, we are unable to make mips64el version of [alpine](https://www.alpinelinux.org/), so we have to replace the alpine to existing MIPS images, such as Debian-stretch, fedora, ubuntu. Replacing the base image also requires replacing the command to install the dependencies, even the version of these dependencies.
Some images are not in `kubernetes/test/images`, such as `gcr.io/google-samples/gb-frontend:v6`. There is no clear documentation explaining where these images are locaated, though we found the source code in repository [github.com/GoogleCloudPlatform/kubernetes-engine-samples](https://github.com/GoogleCloudPlatform/kubernetes-engine-samples). We soon ran into new problems: to build these google sample images, we have to build the base image it uses, even the base image of the base images, such as `php:5-apache`, `redis`, and `perl`.
After a long process of building an image, we finished with about four dozen images, including the images used by the test pod, and the base images. The last step before we run the tests is to place all those images into every node in the cluster and make sure the Pod image pull policy is `imagePullPolicy: ifNotPresent`.
Finally, we ran the tests and got the test result, include `e2e.log`, which showed that all test cases passed. Additionally, we submitted our test result to [k8s-conformance](https://github.com/cncf/k8s-conformance) as a [pull request](https://github.com/cncf/k8s-conformance/pull/779).
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_Figure 5 Pull request for conformance test results_
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_图五 一致性测试结果的 PR_
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## What's next
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## 后续计划
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We built the kubernetes-MIPS component manually and finished the conformance test, which verified the feasibility of Kubernetes On the MIPS platform and greatly enhanced our confidence in promoting the support of the MIPS architecture by Kubernetes.
In the future, we plan to actively contribute our experience and achievements to the community, submit PR, and patch for MIPS. We hope that more developers and companies in the community join us and promote Kubernetes on MIPS.
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后续，我们将积极地向社区贡献我们的工作经验以及成果，提交 PR 以及 Patch For MIPS 等， 希望能够有更多的来自社区的力量加入进来，共同推进 Kubernetes for MIPS 的进程。
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Contribution plan：
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后续开源贡献计划：
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- contribute the source of e2e test images for MIPS
- contribute the source of hyperkube for MIPS
- contribute the source of deploy tools like kubeadm for MIPS
