1、crd介紹

CustomResourceDefinitions,是一種可以定製資源擴展Kubernetes API的使用。

2、使用kubebuilder開發crd

Kubebuilder 是一個使用 CRDs 構建 K8s API 的 SDK，主要是：

提供腳手架工具初始化 CRDs 工程，自動生成 boilerplate 代碼和配置；
提供代碼庫封裝底層的 K8s go-client；

2.1 準備環境

go version go1.13.3 linux/amd64
Docker version 18.06.0-ce, build 0ffa825
kubectl Client Version: version.Info{Major:"1", Minor:"15", GitVersion:"v1.15.2", GitCommit:"f6278300bebbb750328ac16ee6dd3aa7d3549568", GitTreeState:"clean", BuildDate:"2019-08-05T09:23:26Z", GoVersion:"go1.12.5", Compiler:"gc", Platform:"linux/amd64"}
kubectl Server Version: version.Info{Major:"1", Minor:"17", GitVersion:"v1.17.0", GitCommit:"70132b0f130acc0bed193d9ba59dd186f0e634cf", GitTreeState:"clean", BuildDate:"2019-12-07T21:12:17Z", GoVersion:"go1.13.4", Compiler:"gc", Platform:"linux/amd64"}
kustomize version:Version: {KustomizeVersion:3.0.3 GitCommit:30b378a9244d757c1cda31b95694fabd6cbdb8e1 BuildDate:2019-07-18T17:45:11Z GoOs:linux GoArch:amd64}
k8s 集羣

2.2 創建一個項目

命令如下：

kubebuilder init --domain my.domain

需要先用go mod init命令初始化模塊，會在項目根目錄下生成 go.mod 文件

創建完project之後，你會得到如下的代碼包結構

2.3 創建api

命令如下：

kubebuilder create api --group webapp --version v1 --kind Guestbook

發現有報錯，cannot load example.com/m/api/v1: cannot find module providing package example.com/m/api/v1

簡單起見，可以把生成的項目代碼放到$GOPATH/src/example.com/$moduleName下

代碼包結構變成了這樣子：

下面開始我們的重頭戲-編譯

2.4、編譯

第一步：修改DockerFile，記得關掉go mod

改一下dockerfile

# Build the manager binary
FROM golang:1.12.7 as builder

WORKDIR /workspace
# Copy the Go Modules manifests
# COPY go.mod go.mod
# COPY go.sum go.sum
# cache deps before building and copying source so that we don't need to re-download as much
# and so that source changes don't invalidate our downloaded layer
# RUN go mod download

# Copy the go source
# COPY main.go main.go
# COPY api/ api/
# COPY controllers/ controllers/
COPY . .

# Build
RUN  go build -a -o manager main.go

# Use distroless as minimal base image to package the manager binary
# Refer to https://github.com/GoogleContainerTools/distroless for more details
FROM golang:1.12.7
WORKDIR /
COPY --from=builder /workspace/manager .
ENTRYPOINT ["/manager"]

第二步：修改Makefile

# docker-build: test

docker-build:

make docker-build IMG=testaa:0.1，真正的命令有兩個

1、docker build . -t ${IMG}，這個其實是調用DockerFile執行的

2、sed -i'' -e 's@image: .*@image: '"${IMG}"'@' ./config/default/manager_image_patch.yaml

第三步：構建鏡像

make docker build controller:latest

輸出如下：

docker build . -t controller:latest
Sending build context to Docker daemon  68.94MB
Step 1/10 : FROM golang:1.12.7 as builder
 ---> be63d15101cb
Step 2/10 : WORKDIR /workspace
 ---> Running in e6b2a339d69d
Removing intermediate container e6b2a339d69d
 ---> 3d31fe5fe0d3
Step 3/10 : RUN mkdir -p /go/src/example.com/m && cd /go/src/example.com/m
 ---> Running in a3b5bd085aa6
Removing intermediate container a3b5bd085aa6
 ---> 6d5b1b2d164e
Step 4/10 : WORKDIR /go/src/example.com/m
 ---> Running in dbbfdb9460d8
Removing intermediate container dbbfdb9460d8
 ---> 50b2be51a7f2
Step 5/10 : COPY . .
 ---> 1d274ef3a35e
Step 6/10 : RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 GO111MODULE=off go build -a -o manager main.go
 ---> Running in 4bf405566754
Removing intermediate container 4bf405566754
 ---> d6c506ecfe82
Step 7/10 : FROM golang:1.12.7
 ---> be63d15101cb
Step 8/10 : WORKDIR /
 ---> Running in 5f6b7f9f350e
Removing intermediate container 5f6b7f9f350e
 ---> 76876c7e986f
Step 9/10 : COPY --from=builder /go/src/example.com/m/manager .
 ---> 92313bcb89dc
Step 10/10 : ENTRYPOINT ["/manager"]
 ---> Running in e645ad3860de
Removing intermediate container e645ad3860de
 ---> 17f7fc4debad
Successfully built 17f7fc4debad
Successfully tagged controller:latest
updating kustomize image patch file for manager resource
sed -i'' -e 's@image: .*@image: '"controller:latest"'@' ./config/default/manager_image_patch.yaml
make: *** No rule to make target `testaa:0.1'.  Stop.