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将 Docker Compose 文件转换为 Kubernetes 资源

Kompose 是什么?它是个转换工具,可将 compose(即 Docker Compose)所组装的所有内容转换成容器编排器(Kubernetes 或 OpenShift)可识别的形式。

更多信息请参考 Kompose 官网 http://kompose.io

准备开始

您必须拥有一个 Kubernetes 集群,并且必须使用 kubectl 命令行工具与你的集群进行通信。如果您还没有一个集群,您可以通过 Minikube 创建一个集群,或者使用这些 Kubernetes playground :

To check the version, enter kubectl version.

安装 Kompose

我们有很多种方式安装 Kompose。首选方式是从最新的 GitHub 发布页面下载二进制文件。

GitHub 发布版本

Kompose 通过 GitHub 发布版本,发布周期为三星期。您可以在GitHub 发布页面上看到所有当前版本。

# Linux
curl -L https://github.com/kubernetes/kompose/releases/download/v1.16.0/kompose-linux-amd64 -o kompose

# macOS
curl -L https://github.com/kubernetes/kompose/releases/download/v1.16.0/kompose-darwin-amd64 -o kompose

# Windows
curl -L https://github.com/kubernetes/kompose/releases/download/v1.16.0/kompose-windows-amd64.exe -o kompose.exe

chmod +x kompose
sudo mv ./kompose /usr/local/bin/kompose

或者,您可以下载 tarball

Go

go get 命令从主分支拉取最新的开发变更的方法安装 Kompose。

go get -u github.com/kubernetes/kompose

CentOS

Kompose 位于 EPEL CentOS 代码仓库。 如果您还没有安装启用 EPEL 代码仓库,请运行命令 sudo yum install epel-release

如果您的系统中已经启用了 EPEL,您就可以像安装其他软件包一样安装 Kompose。

sudo yum -y install kompose

Fedora

Kompose 位于 Fedora 24、25 和 26 的代码仓库。您可以像安装其他软件包一样安装 Kompose。

sudo dnf -y install kompose

macOS

在 macOS 上您可以通过 Homebrew 安装 Kompose 的最新版本:

brew install kompose

使用 Kompose

再需几步,我们就把你从 Docker Compose 带到 Kubernetes。 您只需要一个现有的 docker-compose.yml 文件。

  1. 进入 docker-compose.yml 文件所在的目录。如果没有,请使用下面这个进行测试。

      version: "2"
    
      services:
    
        redis-master:
          image: k8s.gcr.io/redis:e2e
          ports:
            - "6379"
    
        redis-slave:
          image: gcr.io/google_samples/gb-redisslave:v1
          ports:
            - "6379"
          environment:
            - GET_HOSTS_FROM=dns
    
        frontend:
          image: gcr.io/google-samples/gb-frontend:v4
          ports:
            - "80:80"
          environment:
            - GET_HOSTS_FROM=dns
          labels:
            kompose.service.type: LoadBalancer
  2. 运行 kompose up 命令直接部署到 Kubernetes,或者跳到下一步,生成 kubectl 使用的文件。

      $ kompose up
      We are going to create Kubernetes Deployments, Services and PersistentVolumeClaims for your Dockerized application.
      If you need different kind of resources, use the 'kompose convert' and 'kubectl create -f' commands instead.
    
      INFO Successfully created Service: redis          
      INFO Successfully created Service: web            
      INFO Successfully created Deployment: redis       
      INFO Successfully created Deployment: web         
    
      Your application has been deployed to Kubernetes. You can run 'kubectl get deployment,svc,pods,pvc' for details.
  3. 要将 docker-compose.yml 转换为 kubectl 可用的文件,请运行 kompose convert 命令进行转换,然后运行 kubectl create -f <output file> 进行创建。

      $ kompose convert                           
      INFO Kubernetes file "frontend-service.yaml" created         
      INFO Kubernetes file "redis-master-service.yaml" created     
      INFO Kubernetes file "redis-slave-service.yaml" created      
      INFO Kubernetes file "frontend-deployment.yaml" created      
      INFO Kubernetes file "redis-master-deployment.yaml" created  
      INFO Kubernetes file "redis-slave-deployment.yaml" created   
      $ kubectl create -f frontend-service.yaml,redis-master-service.yaml,redis-slave-service.yaml,frontend-deployment.yaml,redis-master-deployment.yaml,redis-slave-deployment.yaml
      service/frontend created
      service/redis-master created
      service/redis-slave created
      deployment.apps/frontend created
      deployment.apps/redis-master created
      deployment.apps/redis-slave created

    您部署的应用在 Kubernetes 中运行起来了。

  4. 访问您的应用。

    如果您在开发过程中使用 minikube,请执行:

      $ minikube service frontend

    否则,我们要查看一下您的服务使用了什么 IP!

      $ kubectl describe svc frontend
      Name:                   frontend
      Namespace:              default
      Labels:                 service=frontend
      Selector:               service=frontend
      Type:                   LoadBalancer
      IP:                     10.0.0.183
      LoadBalancer Ingress:   123.45.67.89
      Port:                   80      80/TCP
      NodePort:               80      31144/TCP
      Endpoints:              172.17.0.4:80
      Session Affinity:       None
      No events.

    如果您使用的是云提供商,您的 IP 将在 LoadBalancer Ingress 字段给出。

      $ curl http://123.45.67.89

用户指南

Kompose 支持两种驱动:OpenShift 和 Kubernetes。 您可以通过全局选项 --provider 选择驱动方式。如果没有指定,会将 Kubernetes 作为默认驱动。

kompose convert

Kompose 支持将 V1、V2 和 V3 版本的 Docker Compose 文件转换为 Kubernetes 和 OpenShift 资源对象。

Kubernetes

$ kompose --file docker-voting.yml convert
WARN Unsupported key networks - ignoring
WARN Unsupported key build - ignoring
INFO Kubernetes file "worker-svc.yaml" created
INFO Kubernetes file "db-svc.yaml" created
INFO Kubernetes file "redis-svc.yaml" created
INFO Kubernetes file "result-svc.yaml" created
INFO Kubernetes file "vote-svc.yaml" created
INFO Kubernetes file "redis-deployment.yaml" created
INFO Kubernetes file "result-deployment.yaml" created
INFO Kubernetes file "vote-deployment.yaml" created
INFO Kubernetes file "worker-deployment.yaml" created
INFO Kubernetes file "db-deployment.yaml" created

$ ls
db-deployment.yaml  docker-compose.yml         docker-gitlab.yml  redis-deployment.yaml  result-deployment.yaml  vote-deployment.yaml  worker-deployment.yaml
db-svc.yaml         docker-voting.yml          redis-svc.yaml     result-svc.yaml        vote-svc.yaml           worker-svc.yaml

您也可以同时提供多个 docker-compose 文件进行转换:

$ kompose -f docker-compose.yml -f docker-guestbook.yml convert
INFO Kubernetes file "frontend-service.yaml" created         
INFO Kubernetes file "mlbparks-service.yaml" created         
INFO Kubernetes file "mongodb-service.yaml" created          
INFO Kubernetes file "redis-master-service.yaml" created     
INFO Kubernetes file "redis-slave-service.yaml" created      
INFO Kubernetes file "frontend-deployment.yaml" created      
INFO Kubernetes file "mlbparks-deployment.yaml" created      
INFO Kubernetes file "mongodb-deployment.yaml" created       
INFO Kubernetes file "mongodb-claim0-persistentvolumeclaim.yaml" created
INFO Kubernetes file "redis-master-deployment.yaml" created  
INFO Kubernetes file "redis-slave-deployment.yaml" created   

$ ls
mlbparks-deployment.yaml  mongodb-service.yaml                       redis-slave-service.jsonmlbparks-service.yaml  
frontend-deployment.yaml  mongodb-claim0-persistentvolumeclaim.yaml  redis-master-service.yaml
frontend-service.yaml     mongodb-deployment.yaml                    redis-slave-deployment.yaml
redis-master-deployment.yaml

当提供多个 docker-compose 文件时,配置将会合并。任何通用的配置都将被后续文件覆盖。

OpenShift

$ kompose --provider openshift --file docker-voting.yml convert
WARN [worker] Service cannot be created because of missing port.
INFO OpenShift file "vote-service.yaml" created             
INFO OpenShift file "db-service.yaml" created               
INFO OpenShift file "redis-service.yaml" created            
INFO OpenShift file "result-service.yaml" created           
INFO OpenShift file "vote-deploymentconfig.yaml" created    
INFO OpenShift file "vote-imagestream.yaml" created         
INFO OpenShift file "worker-deploymentconfig.yaml" created  
INFO OpenShift file "worker-imagestream.yaml" created       
INFO OpenShift file "db-deploymentconfig.yaml" created      
INFO OpenShift file "db-imagestream.yaml" created           
INFO OpenShift file "redis-deploymentconfig.yaml" created   
INFO OpenShift file "redis-imagestream.yaml" created        
INFO OpenShift file "result-deploymentconfig.yaml" created  
INFO OpenShift file "result-imagestream.yaml" created  

kompose 还支持为服务中的构建指令创建 buildconfig。 默认情况下,它使用当前 git 分支的 remote 仓库作为源仓库,使用当前分支作为构建的源分支。 您可以分别使用 --build-repo--build-branch 选项指定不同的源仓库和分支。

$ kompose --provider openshift --file buildconfig/docker-compose.yml convert
WARN [foo] Service cannot be created because of missing port.
INFO OpenShift Buildconfig using git@github.com:rtnpro/kompose.git::master as source.
INFO OpenShift file "foo-deploymentconfig.yaml" created     
INFO OpenShift file "foo-imagestream.yaml" created          
INFO OpenShift file "foo-buildconfig.yaml" created
Note:

如果使用 oc create -f 手动推送 Openshift 工件,则需要确保在构建配置工件之前推送 imagestream 工件,以解决 Openshift 的这个问题:https://github.com/openshift/origin/issues/4518

kompose up

Kompose 支持通过 kompose up 直接将您的”复合的(composed)” 应用程序部署到 Kubernetes 或 OpenShift。

Kubernetes

$ kompose --file ./examples/docker-guestbook.yml up
We are going to create Kubernetes deployments and services for your Dockerized application.
If you need different kind of resources, use the 'kompose convert' and 'kubectl create -f' commands instead.

INFO Successfully created service: redis-master   
INFO Successfully created service: redis-slave    
INFO Successfully created service: frontend       
INFO Successfully created deployment: redis-master
INFO Successfully created deployment: redis-slave
INFO Successfully created deployment: frontend    

Your application has been deployed to Kubernetes. You can run 'kubectl get deployment,svc,pods' for details.

$ kubectl get deployment,svc,pods
NAME                                              DESIRED       CURRENT       UP-TO-DATE   AVAILABLE   AGE
deployment.extensions/frontend                    1             1             1            1           4m
deployment.extensions/redis-master                1             1             1            1           4m
deployment.extensions/redis-slave                 1             1             1            1           4m

NAME                         TYPE               CLUSTER-IP    EXTERNAL-IP   PORT(S)      AGE
service/frontend             ClusterIP          10.0.174.12   <none>        80/TCP       4m
service/kubernetes           ClusterIP          10.0.0.1      <none>        443/TCP      13d
service/redis-master         ClusterIP          10.0.202.43   <none>        6379/TCP     4m
service/redis-slave          ClusterIP          10.0.1.85     <none>        6379/TCP     4m

NAME                                READY         STATUS        RESTARTS     AGE
pod/frontend-2768218532-cs5t5       1/1           Running       0            4m
pod/redis-master-1432129712-63jn8   1/1           Running       0            4m
pod/redis-slave-2504961300-nve7b    1/1           Running       0            4m

注意

OpenShift

$ kompose --file ./examples/docker-guestbook.yml --provider openshift up
We are going to create OpenShift DeploymentConfigs and Services for your Dockerized application.
If you need different kind of resources, use the 'kompose convert' and 'oc create -f' commands instead.

INFO Successfully created service: redis-slave    
INFO Successfully created service: frontend       
INFO Successfully created service: redis-master   
INFO Successfully created deployment: redis-slave
INFO Successfully created ImageStream: redis-slave
INFO Successfully created deployment: frontend    
INFO Successfully created ImageStream: frontend   
INFO Successfully created deployment: redis-master
INFO Successfully created ImageStream: redis-master

Your application has been deployed to OpenShift. You can run 'oc get dc,svc,is' for details.

$ oc get dc,svc,is
NAME               REVISION                              DESIRED       CURRENT    TRIGGERED BY
dc/frontend        0                                     1             0          config,image(frontend:v4)
dc/redis-master    0                                     1             0          config,image(redis-master:e2e)
dc/redis-slave     0                                     1             0          config,image(redis-slave:v1)
NAME               CLUSTER-IP                            EXTERNAL-IP   PORT(S)    AGE
svc/frontend       172.30.46.64                          <none>        80/TCP     8s
svc/redis-master   172.30.144.56                         <none>        6379/TCP   8s
svc/redis-slave    172.30.75.245                         <none>        6379/TCP   8s
NAME               DOCKER REPO                           TAGS          UPDATED
is/frontend        172.30.12.200:5000/fff/frontend                     
is/redis-master    172.30.12.200:5000/fff/redis-master                 
is/redis-slave     172.30.12.200:5000/fff/redis-slave    v1  

注意

kompose down

您一旦将”复合(composed)” 应用部署到 Kubernetes,$ kompose down 命令将能帮您通过删除 Deployment 和 Service 对象来删除应用。如果需要删除其他资源,请使用 ‘kubectl’ 命令。

$ kompose --file docker-guestbook.yml down
INFO Successfully deleted service: redis-master   
INFO Successfully deleted deployment: redis-master
INFO Successfully deleted service: redis-slave    
INFO Successfully deleted deployment: redis-slave
INFO Successfully deleted service: frontend       
INFO Successfully deleted deployment: frontend

注意

构建和推送 Docker 镜像

Kompose 支持构建和推送 Docker 镜像。如果 Docker Compose 文件中使用了 build 关键字,您的镜像将会:

使用 Docker Compose 文件示例

version: "2"

services:
    foo:
        build: "./build"
        image: docker.io/foo/bar

使用带有 build 键的 kompose up 命令:

$ kompose up
INFO Build key detected. Attempting to build and push image 'docker.io/foo/bar'
INFO Building image 'docker.io/foo/bar' from directory 'build'
INFO Image 'docker.io/foo/bar' from directory 'build' built successfully
INFO Pushing image 'foo/bar:latest' to registry 'docker.io'
INFO Attempting authentication credentials 'https://index.docker.io/v1/
INFO Successfully pushed image 'foo/bar:latest' to registry 'docker.io'
INFO We are going to create Kubernetes Deployments, Services and PersistentVolumeClaims for your Dockerized application. If you need different kind of resources, use the 'kompose convert' and 'kubectl create -f' commands instead.

INFO Deploying application in "default" namespace
INFO Successfully created Service: foo            
INFO Successfully created Deployment: foo         

Your application has been deployed to Kubernetes. You can run 'kubectl get deployment,svc,pods,pvc' for details.

要想禁用该功能,或者使用 BuildConfig 中的版本(在 OpenShift 中),可以通过传递 --build (local|build-config|none) 参数来实现。

# Disable building/pushing Docker images
$ kompose up --build none

# Generate Build Config artifacts for OpenShift
$ kompose up --provider openshift --build build-config

其他转换方式

默认的 kompose 转换会生成 yaml 格式的 Kubernetes DeploymentService 对象。 您可以选择通过 -j 参数生成 json 格式的对象。 您也可以替换生成 Replication Controllers 对象、Daemon SetsHelm charts。

$ kompose convert -j
INFO Kubernetes file "redis-svc.json" created
INFO Kubernetes file "web-svc.json" created
INFO Kubernetes file "redis-deployment.json" created
INFO Kubernetes file "web-deployment.json" created

*-deployment.json 文件中包含 Deployment 对象。

$ kompose convert --replication-controller
INFO Kubernetes file "redis-svc.yaml" created
INFO Kubernetes file "web-svc.yaml" created
INFO Kubernetes file "redis-replicationcontroller.yaml" created
INFO Kubernetes file "web-replicationcontroller.yaml" created

*-replicationcontroller.yaml 文件包含 Replication Controller 对象。如果您想指定副本数(默认为 1),可以使用 --replicas 参数:$ kompose convert --replication-controller --replicas 3

$ kompose convert --daemon-set
INFO Kubernetes file "redis-svc.yaml" created
INFO Kubernetes file "web-svc.yaml" created
INFO Kubernetes file "redis-daemonset.yaml" created
INFO Kubernetes file "web-daemonset.yaml" created

*-daemonset.yaml 文件包含 Daemon Set 对象。

如果您想生成 Helm 可用的 Chart,只需简单的执行下面的命令:

$ kompose convert -c
INFO Kubernetes file "web-svc.yaml" created
INFO Kubernetes file "redis-svc.yaml" created
INFO Kubernetes file "web-deployment.yaml" created
INFO Kubernetes file "redis-deployment.yaml" created
chart created in "./docker-compose/"

$ tree docker-compose/
docker-compose
├── Chart.yaml
├── README.md
└── templates
    ├── redis-deployment.yaml
    ├── redis-svc.yaml
    ├── web-deployment.yaml
    └── web-svc.yaml

这个图标结构旨在为构建 Helm Chart 提供框架。

标签

kompose 支持 docker-compose.yml 文件中用于 Kompose 的标签,以便在转换时明确定义 Service 的行为。

version: "2"
services:
  nginx:
    image: nginx
    dockerfile: foobar
    build: ./foobar
    cap_add:
      - ALL
    container_name: foobar
    labels:
      kompose.service.type: nodeport

例如:

version: "2"
services:
  web:
    image: tuna/docker-counter23
    ports:
     - "5000:5000"
    links:
     - redis
    labels:
      kompose.service.expose: "counter.example.com"
  redis:
    image: redis:3.0
    ports:
     - "6379"

当前支持的选项有:

kompose.service.type nodeport / clusterip / loadbalancer
kompose.service.expose true / hostname
Note:

kompose.service.type 标签应该只用ports来定义,否则 kompose 会失败。

重启

如果你想创建没有控制器的普通 Pod,可以使用 docker-compose 的 restart 结构来定义它。请参考下表了解 restart 的不同参数。

docker-compose restart 创建的对象 Pod restartPolicy
"" 控制器对象 Always
always 控制器对象 Always
on-failure Pod OnFailure
no Pod Never
Note:

控制器对象可以是 deploymentreplicationcontroller 等。

例如,pival Service 将在这里变成 Pod。这个容器的计算值为 pi

version: '2'

services:
  pival:
    image: perl
    command: ["perl",  "-Mbignum=bpi", "-wle", "print bpi(2000)"]
    restart: "on-failure"

关于 Deployment Config 的提醒

如果 Docker Compose 文件中为服务声明了卷,Deployment (Kubernetes) 或 DeploymentConfig (OpenShift) 的策略会从 “RollingUpdate” (默认) 变为 “Recreate”。 这样做的目的是为了避免服务的多个实例同时访问卷。

如果 Docker Compose 文件中的服务名包含 _ (例如 web_service),那么将会被替换为 -,服务也相应的会重命名(例如 web-service)。 Kompose 这样做的原因是 “Kubernetes” 不允许对象名称中包含 _

Docker Compose 版本

Kompose 支持的 Docker Compose 版本包括:1、2 和 3。有限支持 2.1 和 3.2 版本,因为它们还在实验阶段。

所有三个版本的兼容性列表请查看我们的 转换文档,文档中列出了所有不兼容的 Docker Compose 关键字。

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