Yurtctl convert/revert
1.背景说明
由于 OpenYurt 对 Kubernetes 无侵入，所以 OpenYurt 提供了 Yurtctl convert/revert 命令，用于 Kubernetes 集群和 OpenYurt 集群的转换。该命令适用于测试环境，不推荐在生产环境中使用。
2.使用流程
2.1编译 Yurtctl
要快速构建和安装设置 yurtctl ，在编译系统已安装了 golang 1.13+ 和 bash 的前提下你可以执行以下命令来完成安装：
```sh
$ git clone https://github.com/openyurtio/openyurt.git
$ cd openyurt
$ make build WHAT="yurtctl" ARCH="amd64" REGION=cn
```
生成的可执行文件将存放在 _output/bin/ 目录下。
2.2 Kubernetes To OpenYurt
在测试环境中，当用户已经拥有一个 Kubernetes 集群时，可以使用 Yurtctl convert 命令，快速地将集群转换为 OpenYurt 集群。目前，OpenYurt 支持 minkube、kind 以及手动搭建的 Kubernetes 集群的转换。
查看原生 Kubernetes 集群：
$ kubectl get node
NAME STATUS ROLES AGE VERSION
master Ready control-plane,master 24d v1.20.0
node1 Ready <none> 24d v1.20.0
node2 Ready <none> 24d v1.20.0
使用 Yurtctl convert 命令进行集群转换。转换时，需要指定集群中的云端节点列表。
$ _output/bin/yurtctl convert --provider ack --cloud-nodes master
[preflight] Running pre-flight checks
[preflight] Running node-servant-preflight-convert jobs to check on edge and cloud nodes. Job running may take a long time, and job failure will affect the execution of the next stage
[runConvert] Label all nodes with edgeworker label, annotate all nodes with autonomy annotation
[runConvert] Deploying yurt-controller-manager
[runConvert] Running jobs for convert. Job running may take a long time, and job failure will not affect the execution of the next stage
[runConvert] Running disable-node-controller jobs to disable node-controller
[INFO] servant job(yurtctl-disable-node-controller-master) has succeeded
[runConvert] Running node-servant-convert jobs to deploy the yurt-hub and reset the kubelet service on edge and cloud nodes
[INFO] servant job(node-servant-convert-node1) has succeeded
[INFO] servant job(node-servant-convert-node2) has succeeded
[INFO] servant job(node-servant-convert-master) has succeeded
[runConvert] If any job fails, you can get job information through 'kubectl get jobs -n kube-system' to debug.
Note that before the next conversion, please delete all related jobs so as not to affect the conversion.
转换完成之后，集群中会部署 yurt-controller-manager，yurt-hub 等组件。此外，边缘节点会自动开启节点自治功能。
在转换时 Yurtctl 提供了选项，用户可以选择设置 OpenYurt 集群的配置：
--deploy-yurttunnel 是否部署 yurttunnel-server 以及 yurttunnel-agent
--enable-app-manager 是否部署 yurt-app-manager
--yurthub-image yurthub 镜像
--yurt-controller-manager-image yurt-controller-manager 镜像
--yurt-tunnel-server-image yurttunnel-server 镜像
--yurt-tunnel-agent-image yurttunnel-agent 镜像
--yurt-app-manager-image yurt-app-manager-image 镜像
更多配置可以使用 yurtctl convert -h 获取。
注意：如果转换失败，请查询失败的 Job 的运行情况进行错误排查，并删除相关的 Job，以避免下一次转换发生错误。
2.3 OpenYurt To Kubernetes
OpenYurt 集群状况：
$ kubectl get pod -A
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system coredns-54d67798b7-28r2s 1/1 Running 0 24d
kube-system coredns-54d67798b7-wlmh8 1/1 Running 0 24d
kube-system etcd-master 1/1 Running 0 24d
kube-system kube-apiserver-master 1/1 Running 0 24d
kube-system kube-controller-manager-master 1/1 Running 0 13d
kube-system kube-flannel-ds-4fmxr 1/1 Running 0 24d
kube-system kube-flannel-ds-7r2fh 1/1 Running 0 24d
kube-system kube-flannel-ds-j2xs5 1/1 Running 0 24d
kube-system kube-proxy-6jh7s 1/1 Running 0 24d
kube-system kube-proxy-9zdnz 1/1 Running 0 24d
kube-system kube-proxy-trw2v 1/1 Running 0 24d
kube-system kube-scheduler-master 1/1 Running 0 24d
kube-system yurt-controller-manager-77b97fd47b-mhhxq 1/1 Running 0 13d
kube-system yurt-hub-master 1/1 Running 0 13d
kube-system yurt-hub-node1 1/1 Running 0 13d
kube-system yurt-hub-node2 1/1 Running 0 13d
在测试环境中，通过执行以下命令将 OpenYurt 集群转换为 Kubernetes 集群：
$ ./yurtctl revert
I0107 11:36:25.694505 8473 revert.go:169] yurt controller manager is removed
I0107 11:36:25.703390 8473 revert.go:178] serviceaccount for yurt controller manager is removed
I0107 11:36:25.706450 8473 revert.go:187] clusterrole for yurt controller manager is removed
I0107 11:36:25.709956 8473 revert.go:196] clusterrolebinding for yurt controller manager is removed
I0107 11:36:25.720702 8473 revert.go:356] deployment for yurt app manager is removed
I0107 11:36:25.721580 8473 revert.go:366] Role for yurt app manager is removed
I0107 11:36:25.722411 8473 revert.go:375] ClusterRole for yurt app manager is removed
I0107 11:36:25.723257 8473 revert.go:384] ClusterRoleBinding for yurt app manager is removed
I0107 11:36:25.724132 8473 revert.go:394] RoleBinding for yurt app manager is removed
I0107 11:36:25.870416 8473 revert.go:404] secret for yurt app manager is removed
I0107 11:36:26.070564 8473 revert.go:414] Service for yurt app manager is removed
I0107 11:36:26.071558 8473 revert.go:424] MutatingWebhookConfiguration for yurt app manager is removed
I0107 11:36:26.072505 8473 revert.go:434] ValidatingWebhookConfiguration for yurt app manager is removed
I0107 11:36:26.082843 8473 revert.go:443] crd for yurt app manager is removed
I0107 11:36:26.092951 8473 revert.go:452] UnitedDeploymentcrd for yurt app manager is removed
I0107 11:36:26.092968 8473 revert.go:212] yurt app manager is removed
[INFO] servant job(yurtctl-enable-node-controller-master) has succeeded
I0107 11:36:56.118458 8473 revert.go:226] complete enabling node-controller
[INFO] servant job(node-servant-revert-node1) has succeeded
[INFO] servant job(node-servant-revert-node2) has succeeded
[INFO] servant job(node-servant-revert-master) has succeeded
I0107 11:37:16.135272 8473 revert.go:239] complete removing yurt-hub and resetting kubelet service
I0107 11:37:16.148484 8473 revert.go:246] delete yurthub clusterrole and clusterrolebinding
I0107 11:37:16.155288 8473 revert.go:262] label openyurt.io/is-edge-worker is removed from node master
I0107 11:37:16.155303 8473 revert.go:264] annotation node.beta.openyurt.io/autonomy is removed from node master
I0107 11:37:16.159211 8473 revert.go:262] label openyurt.io/is-edge-worker is removed from node node1
I0107 11:37:16.159229 8473 revert.go:264] annotation node.beta.openyurt.io/autonomy is removed from node node1
I0107 11:37:16.163365 8473 revert.go:262] label openyurt.io/is-edge-worker is removed from node node2
I0107 11:37:16.163384 8473 revert.go:264] annotation node.beta.openyurt.io/autonomy is removed from node node2
注意，在执行前需要确保所有边缘节点状态正常，以避免转换过程中发生错误。