準(zhǔn)備開始

你必須擁有一個(gè) Kubernetes 的集群，同時(shí)你必須配置 kubectl 命令行工具與你的集群通信。 建議在至少有兩個(gè)不作為控制平面主機(jī)的節(jié)點(diǎn)的集群上運(yùn)行本教程。

安裝 Kompose

我們有很多種方式安裝 Kompose。首選方式是從最新的 GitHub 發(fā)布頁面下載二進(jìn)制文件。

Kompose 通過 GitHub?安裝

# Linux
curl -L https://github.com/kubernetes/kompose/releases/download/v1.26.0/kompose-linux-amd64 -o kompose

# macOS
curl -L https://github.com/kubernetes/kompose/releases/download/v1.26.0/kompose-darwin-amd64 -o kompose

# Windows
curl -L https://github.com/kubernetes/kompose/releases/download/v1.26.0/kompose-windows-amd64.exe -o kompose.exe

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

使用 Kompose

只需幾步，我們就把你從 Docker Compose 帶到 Kubernetes。 你只需要一個(gè)現(xiàn)有的?docker-compose.yml?文件。

1. 進(jìn)入?docker-compose.yml?文件所在的目錄。如果沒有，請(qǐng)使用下面這個(gè)進(jìn)行測(cè)試。

   version: "2"
   
   services:
   
     redis-master:
       image: registry.k8s.io/redis:e2e
       ports:
         - "6379"
   
     redis-slave:
       image: gcr.io/google_samples/gb-redisslave:v3
       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
   

1. 要將?docker-compose.yml?轉(zhuǎn)換為?kubectl?可用的文件，請(qǐng)運(yùn)行?kompose convert?命令進(jìn)行轉(zhuǎn)換，然后運(yùn)行?kubectl apply -f <output file>?進(jìn)行創(chuàng)建。

   kompose convert                           
   

   輸出類似于：

   INFO Kubernetes file "frontend-tcp-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 apply -f frontend-tcp-service.yaml,redis-master-service.yaml,redis-slave-service.yaml,frontend-deployment.yaml,redis-master-deployment.yaml,redis-slave-deployment.yaml
   

   輸出類似于：

   service/frontend-tcp created
   service/redis-master created
   service/redis-slave created
   deployment.apps/frontend created
   deployment.apps/redis-master created
   deployment.apps/redis-slave created
   

   你部署的應(yīng)用在 Kubernetes 中運(yùn)行起來了。

1. 訪問你的應(yīng)用。

   如果你在開發(fā)過程中使用?minikube，請(qǐng)執(zhí)行：

   minikube service frontend
   

   否則，我們要查看一下你的服務(wù)使用了什么 IP！

   kubectl describe svc frontend
   

   Name:                     frontend-tcp
   Namespace:                default
   Labels:                   io.kompose.service=frontend-tcp
   Annotations:              kompose.cmd: kompose convert
                             kompose.service.type: LoadBalancer
                             kompose.version: 1.26.0 (40646f47)
   Selector:                 io.kompose.service=frontend
   Type:                     LoadBalancer
   IP Family Policy:         SingleStack
   IP Families:              IPv4
   IP:                       10.43.67.174
   IPs:                      10.43.67.174
   Port:                     80  80/TCP
   TargetPort:               80/TCP
   NodePort:                 80  31254/TCP
   Endpoints:                10.42.0.25:80
   Session Affinity:         None
   External Traffic Policy:  Cluster
   Events:
     Type    Reason                Age   From                Message
     ----    ------                ----  ----                -------
     Normal  EnsuringLoadBalancer  62s   service-controller  Ensuring load balancer
     Normal  AppliedDaemonSet      62s   service-controller  Applied LoadBalancer DaemonSet kube-system/svclb-frontend-tcp-9362d276
   

   如果你使用的是云驅(qū)動(dòng)，你的 IP 將在?LoadBalancer Ingress?字段給出。

   curl http://192.0.2.89
   

1. 清理。

   你完成示例應(yīng)用 Deployment 的測(cè)試之后，只需在 Shell 中運(yùn)行以下命令，就能刪除用過的資源。

   kubectl delete -f frontend-tcp-service.yaml,redis-master-service.yaml,redis-slave-service.yaml,frontend-deployment.yaml,redis-master-deployment.yaml,redis-slave-deployment.yaml
   

用戶指南

kompose convert

Kompose 支持將 V1、V2 和 V3 版本的 Docker Compose 文件轉(zhuǎn)換為 Kubernetes 和 OpenShift 資源對(duì)象。

Kubernetes?kompose convert?示例

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

你也可以同時(shí)提供多個(gè) docker-compose 文件進(jìn)行轉(zhuǎn)換：

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

當(dāng)提供多個(gè) docker-compose 文件時(shí)，配置將會(huì)合并。任何通用的配置都將被后續(xù)文件覆蓋。

OpenShift?kompose convert?示例

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 還支持為服務(wù)中的構(gòu)建指令創(chuàng)建 buildconfig。 默認(rèn)情況下，它使用當(dāng)前 git 分支的 remote 倉(cāng)庫(kù)作為源倉(cāng)庫(kù)，使用當(dāng)前分支作為構(gòu)建的源分支。 你可以分別使用?--build-repo?和?--build-branch?選項(xiàng)指定不同的源倉(cāng)庫(kù)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

其他轉(zhuǎn)換方式

?默認(rèn)的 kompose 轉(zhuǎn)換會(huì)生成 yaml 格式的 Kubernetes Deployment 和 Service 對(duì)象。 你可以選擇通過 -j 參數(shù)生成 json 格式的對(duì)象。 你也可以替換生成 Replication Controllers 對(duì)象、 DaemonSet 或 Helm Chart。 ?

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 對(duì)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 對(duì)象。 如果你想指定副本數(shù)（默認(rèn)為 1），可以使用?--replicas?參數(shù)：?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 DaemonSet 對(duì)象。

如果你想生成?Helm?可用的 Chart， 只需簡(jiǎn)單的執(zhí)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

這個(gè) Chart 結(jié)構(gòu)旨在為構(gòu)建 Helm Chart 提供框架。

標(biāo)簽

kompose?支持?docker-compose.yml?文件中用于 Kompose 的標(biāo)簽， 以便在轉(zhuǎn)換時(shí)明確定義 Service 的行為。

• kompose.service.type?定義要?jiǎng)?chuàng)建的 Service 類型。例如：

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

• kompose.service.expose?定義是否允許從集群外部訪問 Service。 如果該值被設(shè)置為 "true"，提供程序?qū)⒆詣?dòng)設(shè)置端點(diǎn)， 對(duì)于任何其他值，該值將被設(shè)置為主機(jī)名。 如果在 Service 中定義了多個(gè)端口，則選擇第一個(gè)端口作為公開端口。

  • 如果使用 Kubernetes 驅(qū)動(dòng)，會(huì)有一個(gè) Ingress 資源被創(chuàng)建，并且假定已經(jīng)配置了相應(yīng)的 Ingress 控制器。
  • 如果使用 OpenShift 驅(qū)動(dòng)，則會(huì)有一個(gè) route 被創(chuàng)建。

  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"
  

當(dāng)前支持的選項(xiàng)有:

說明：

kompose.service.type?標(biāo)簽應(yīng)該只用?ports?來定義，否則?kompose?會(huì)失敗。

重啟

如果你想創(chuàng)建沒有控制器的普通 Pod，可以使用 docker-compose 的?restart?結(jié)構(gòu)來指定這一行為。請(qǐng)參考下表了解?restart?的不同參數(shù)。

說明：

控制器對(duì)象可以是?deployment?或?replicationcontroller。

例如，pival?Service 將在這里變成 Pod。這個(gè)容器計(jì)算?pi?的取值。

version: '2'

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

關(guān)于 Deployment Config 的提醒

如果 Docker Compose 文件中為服務(wù)聲明了卷，Deployment（Kubernetes）或 DeploymentConfig（OpenShift）策略會(huì)從 “RollingUpdate”（默認(rèn)）變?yōu)?“Recreate”。 這樣做的目的是為了避免服務(wù)的多個(gè)實(shí)例同時(shí)訪問卷。

如果 Docker Compose 文件中的服務(wù)名包含?_（例如?web_service）， 那么將會(huì)被替換為?-，服務(wù)也相應(yīng)的會(huì)重命名（例如?web-service）。 Kompose 這樣做的原因是 “Kubernetes” 不允許對(duì)象名稱中包含?_。

請(qǐng)注意，更改服務(wù)名稱可能會(huì)破壞一些?docker-compose?文件。

Docker Compose 版本

Kompose 支持的 Docker Compose 版本包括：1、2 和 3。 對(duì) 2.1 和 3.2 版本的支持還有限，因?yàn)樗鼈冞€在實(shí)驗(yàn)階段。

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