云原生 Scaffold 简化Kubernetes应用开发

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 2020/09/07   Share

Skaffold

Skaffold是一个命令行工具，可促进kubernetes本地应用程序的持续开发。Skaffold处理构建，推送和部署应用程序的工作流。

下载skaffold:

快速开始

创建一个Dockerfile
1
FROM alpine
2
3
CMD ["sleep", "300"]

创建一个k8s manifests

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test-skaffold
spec:
  selector:
    matchLabels:
      k8s-app: skaffold
  template:
    metadata:
      labels:
        k8s-app: skaffold
    spec:
      containers:
      - name: test-skaffold
        image: jusene/test-skaffold

skaffold init

apiVersion: skaffold/v2beta7
kind: Config
metadata:
  name: test
build:
  artifacts:
  - image: jusene/test-skaffold
deploy:
  kubectl:
    manifests:
    - k8s-test.yaml

Do you want to write this configuration to skaffold.yaml? [y/n]: y
Configuration skaffold.yaml was written
You can now run [skaffold build] to build the artifacts
or [skaffold run] to build and deploy
or [skaffold dev] to enter development mode, with auto-redeploy

skaffold build 打包镜像
skaffold run 打包镜像并且部署
skaffold dev 源码修改自动打包部署

skaffold 打包多个项目

app
├── app
│   ├── Dockerfile
│   └── kubernetes
│       └── deployment.yaml
├── skaffold.yaml
└── web
    ├── Dockerfile
    └── kubernetes
        └── deployment.yaml

skaffold init

apiVersion: skaffold/v2beta7
kind: Config
metadata:
  name: app
build:
  artifacts:
  - image: jusene/test-skaffold-app
    context: app
  - image: jusene/test-skaffold-web
    context: web
deploy:
  kubectl:
    manifests:
    - app/kubernetes/deployment.yaml
    - web/kubernetes/deployment.yaml

开发模式

skaffold dev采用开发循环，skaffold将监视应用程序的源文件，并在检测到更改后重建镜像发布到集群中。

持续交付

skaffold run是用于一次性部署的单个命令，包括构建，标记，部署和等待部署：

运行状态检查healthcheck，等待deployments稳定并仅在所有部署成功后才成功
skaffold build -构建，标记工件并将其推送到仓库
skaffold deploy -将构建的工件部署到集群
skaffold render -为GitOps工作流程导出转换后的Kubernetes清单

healthcheck默认情况下启用，通过–status-check=false标志禁用它

deploy:
  statusCheckDeadlineSeconds: 300 // 如果未指定，则默认为10分钟
  kubectl:
    manifests:
    - k8s-*

流水线平台

init

skaffold init是在几秒内启动并运行项目的简便方法，生成buid和deploy配置。

skaffold init走任何的构建配置项目目录，并期待文件：Dockerfile,build.gradle/pom.xml,package.json,requiremenets.txt,go.mod。
init跳过大于500mb的文件

kustomize项目部署：通常结构目录

app/      <- application source code, along with build configuration
  main.go
  Dockerfile
...
base/     <- base deploy configuration
  kustomization.yaml
  deployment.yaml
overlays/ <- one or more nested directories, each with modified environment configuration
  dev/
    deployment.yaml
    kustomization.yaml
  prod/
...

退出码：
| 退出码 | 错误 |
| —– | —– |
| 101 | 找不到构建配置｜
| 102 | 找不到或生成k8s清单 |
| 102 | 发现现有的skaffold.yaml |
| 104 | 无法自动将生成器与图像名称匹配 |

build

Docker

本地build，可通过显式local:

1	build:
2	local: {}

成功构建工件后，Docker映像将被推送到远程注册表，要使用本地Docker守护程序，请将构建类型添加local到的build部分：

选项	描述	默认
push	应该将镜像推送到仓库，如果未指定，则仅在当前Kubernetes上下文连接到远程集群时才推送图像
tryImportMissing	如果不在缓存中，是否尝试从docker本地或远程仓库导入	false
useDockerCLI	使用docker命令行界面而不是Docker Engine API
useBuildkit	使用BuildKit构建Docker镜像	false
concurrency	可以同时构建多少个，0表示无限制	1

build:
  artifacts:
  - image: gcr.io/k8s-skaffold/example
  local:
    push: true
    concurrency: 0

Deploy

kubectl

1	deploy:
2	kubectl:
3	manifests:
4	- k8s-*

选项	描述	默认
manifests	kubernetes yaml或json清单	[“k8s/*.yaml”]
remoteManifests	kubernetes体现在远程集群中	[]
flags	传递给其他flag给kubectl
defaultNamespce	如果未提供其他覆盖，则在部署时将默认名称空间传递给kubectl

flags部分提供以下选项:
| 选项 | 描述 | 默认 |
| —– | —– | —– |
| global | 在每个命令上传递其他标志 | [] |
| apply | 在kubectl apply 上传递其他标志 | [] |
| delete | 在kubectl delete 上传递其他标志 | [] |
| disableValidation | 启用后，将–validate=false标志传递给受支持的kubectl命令。| false |

kustomize

kustomize允许Kubernetes开发人员自定义无模板的原始YAML文件，以用于多种用途。

deploy:
  kustomize: {}
# The deploy section above is equal to
# deploy:
#   kustomize:
#     paths: ["."]

选项	描述	默认
paths	kustomization文件的路径	[“.”]
flags	传递给其他flag给kubectl
buildArgs	传递给的其他参数kustomize build	[]
defaultNamespace	如果未提供其他覆盖，则在部署时将默认名称空间传递给kubectl

tag

gitCommit记录使用git commits/references标记镜像
sha256使用latest标记镜像
envTemplate使用环境变量标记镜像
datetime使用当前日期和时间
customTemplate使用模版部件的现有标注器的组合

build:
  tagPolicy:
    gitCommit: {}
  artifacts:
  - image: gcr.io/k8s-skaffold/example

如果工作区在Git标签上，则使用该标签来标记图像

envTemplate允许您在标签中使用环境变量。此策略要求您指定标记模板，在标记过程中，模板的一部分可以用环境变量的值替换。

build:
  tagPolicy:
    envTemplate:
      template: "{{.FOO}}"
  artifacts:
  - image: gcr.io/k8s-skaffold/example

dateTime使用Skaffold开始构建工件的时间作为标签。

build:
  tagPolicy:
    dateTime:
      format: "2006-01-02_15-04-05.999_MST"
      timezone: "Local"
  artifacts:
  - image: gcr.io/k8s-skaffold/example
# The tagPolicy section above is equal to
# tagPolicy:
#   dateTime: {}

filesync

skaffold支持多种同步类型：

manual: 用户必须在本地工作区中指定文件，并在运行容器中指定目标。每种类型的工件都支持此功能。
infer: 每个更改文件的目标是从Dockerfile中的指令推断出来的
auto: Skaffold自动配置同步

manual

build:
  artifacts:
    - image: gcr.io/k8s-skaffold/node-example
      context: node
      sync:
        manual:
          # sync a single file into the `/etc` folder
          - src: '.filebaserc'
            dest: /etc

          # sync files directly below `static-html` into `static/`
          - src: 'static-html/*.html'
            dest: static

          # sync any `png` file into the assets folder
          - src: '**/*.png'
            dest: assets

          # sync all `md` files from `content/en` into `content`
          - src: 'content/en/**/*.md'
            dest: content
            strip: 'content/en/'

infer

对于docker工件，Skaffold知道如何从工件的推断所需的目的地Dockerfile

FROM hugo

ADD .filebaserc /etc/
ADD assets assets/
COPY static-html static/
COPY content/en content/

build:
  artifacts:
    - image: gcr.io/k8s-skaffold/node-example
      context: node
      sync:
        infer:
        - '.filebaserc'
        - 'static-html/*.html'
        - '**/*.png'
        - 'content/en/**/*.md'

port forwarding

portForward:
- resourceType: deployment
  resourceName: myDep
  namespace: mynamespace  # 
  port: 8080 # 
  localPort: 9000 # *Optional*

原文作者：Zhang Jusene

原文链接：http://jusene.github.io/2020/09/07/scaffold/

发表日期：September 7th 2020, 9:30:45 pm

更新日期：November 1st 2020, 1:01:44 pm

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CATALOG

1. Skaffold
2. 快速开始
3. skaffold 打包多个项目
4. 开发模式
5. 持续交付
6. 流水线平台



1	apiVersion: apps/v1
2	kind: Deployment
3	metadata:
4	name: test-skaffold
5	spec:
6	selector:
7	matchLabels:
8	k8s-app: skaffold
9	template:
10	metadata:
11	labels:
12	k8s-app: skaffold
13	spec:
14	containers:
15	- name: test-skaffold
16	image: jusene/test-skaffold

1	skaffold init
2
3	apiVersion: skaffold/v2beta7
4	kind: Config
5	metadata:
6	name: test
7	build:
8	artifacts:
9	- image: jusene/test-skaffold
10	deploy:
11	kubectl:
12	manifests:
13	- k8s-test.yaml
14
15	Do you want to write this configuration to skaffold.yaml? [y/n]: y
16	Configuration skaffold.yaml was written
17	You can now run [skaffold build] to build the artifacts
18	or [skaffold run] to build and deploy
19	or [skaffold dev] to enter development mode, with auto-redeploy

1	app
2	├── app
3	│ ├── Dockerfile
4	│ └── kubernetes
5	│ └── deployment.yaml
6	├── skaffold.yaml
7	└── web
8	├── Dockerfile
9	└── kubernetes
10	└── deployment.yaml

1	deploy:
2	statusCheckDeadlineSeconds: 300 // 如果未指定，则默认为10分钟
3	kubectl:
4	manifests:
5	- k8s-*

1	app/ <- application source code, along with build configuration
2	main.go
3	Dockerfile
4	...
5	base/ <- base deploy configuration
6	kustomization.yaml
7	deployment.yaml
8	overlays/ <- one or more nested directories, each with modified environment configuration
9	dev/
10	deployment.yaml
11	kustomization.yaml
12	prod/
13	...

1	build:
2	artifacts:
3	- image: gcr.io/k8s-skaffold/example
4	local:
5	push: true
6	concurrency: 0

1	deploy:
2	kustomize: {}
3	# The deploy section above is equal to
4	# deploy:
5	# kustomize:
6	# paths: ["."]

1	build:
2	tagPolicy:
3	gitCommit: {}
4	artifacts:
5	- image: gcr.io/k8s-skaffold/example

1	build:
2	tagPolicy:
3	envTemplate:
4	template: "{{.FOO}}"
5	artifacts:
6	- image: gcr.io/k8s-skaffold/example

1	build:
2	tagPolicy:
3	dateTime:
4	format: "2006-01-02_15-04-05.999_MST"
5	timezone: "Local"
6	artifacts:
7	- image: gcr.io/k8s-skaffold/example
8	# The tagPolicy section above is equal to
9	# tagPolicy:
10	# dateTime: {}

1	FROM alpine
2
3	CMD ["sleep", "300"]

1	build:
2	artifacts:
3	- image: gcr.io/k8s-skaffold/node-example
4	context: node
5	sync:
6	manual:
7	# sync a single file into the `/etc` folder
8	- src: '.filebaserc'
9	dest: /etc
10
11	# sync files directly below `static-html` into `static/`
12	- src: 'static-html/*.html'
13	dest: static
14
15	# sync any `png` file into the assets folder
16	- src: '*/.png'
17	dest: assets
18
19	# sync all `md` files from `content/en` into `content`
20	- src: 'content/en/*/.md'
21	dest: content
22	strip: 'content/en/'

1	FROM hugo
2
3	ADD .filebaserc /etc/
4	ADD assets assets/
5	COPY static-html static/
6	COPY content/en content/

1	portForward:
2	- resourceType: deployment
3	resourceName: myDep
4	namespace: mynamespace #
5	port: 8080 #
6	localPort: 9000 # Optional