docker - 将 docker-compose.yml 文件转换为 kubernetes

Question

我正在使用运行以下命令的 kompose 将 docker-compose 文件转换为 kubernetes:

$kompose 转换 -f docker-compose.yml -o kubernetes_image.yaml

命令完成后，输出如下。

WARN Volume mount on the host "/usr/docker/adpater/dbdata" isn't supported - ignoring path on the host
INFO Network integration is detected at Source, shall be converted to equivalent NetworkPolicy at Destination
WARN Volume mount on the host "/usr/docker/adpater/license.json" isn't supported - ignoring path on the host
WARN Volume mount on the host "/usr/docker/adpater/certificates/ssl.crt" isn't supported - ignoring path on the host
WARN Volume mount on the host "/usr/docker/adpater/certificates/ssl.key" isn't supported - ignoring path on the host
WARN Volume mount on the host "/usr/docker/adpater/server.xml" isn't supported - ignoring path on the host
INFO Network integration is detected at Source, shall be converted to equivalent NetworkPolicy at Destination

要将转换后的文件推送到 kubernetes，我运行以下命令:

$kubectl apply -f kubernetes_image.yaml

NAME                      READY   STATUS             RESTARTS   AGE
mysql-557dd849c8-bsdq7    1/1     Running            1          17h
tomcat-7cd65d4556-spjbl   0/1     CrashLoopBackOff   76         18h

如果我运行: $ kubectl 描述 pod tomcat-7cd65d4556-spjbl 我收到以下消息:

Last State:     Terminated
      Reason:       ContainerCannotRun
      Message:      OCI runtime create failed: container_linux.go:349: starting container process caused "process_linux.go:449: container init caused \"rootfs_linux.go:58: mounting \\\"/usr/docker/adapter/server.xml\\\" to rootfs \\\"/var/lib/docker/overlay2/a6df90a0ef4cbe8b2a3fa5352be5f304cd7b648fb1381492308f0a7fceb931cc/merged\\\" at \\\"/var/lib/docker/overlay2/a6df90a0ef4cbe8b2a3fa5352be5f304cd7b648fb1381492308f0a7fceb931cc/merged/usr/local/tomcat/conf/server.xml\\\" caused \\\"not a directory\\\"\"": unknown: Are you trying to mount a directory onto a file (or vice-versa)? Check if the specified host path exists and is the expected type
      Exit Code:    127
      Started:      Sun, 31 May 2020 13:35:00 +0100
      Finished:     Sun, 31 May 2020 13:35:00 +0100
    Ready:          False
    Restart Count:  75
    Environment:    <none>
    Mounts:
      /run/secrets/rji_license.json from tomcat-hostpath0 (rw)
      /usr/local/tomcat/conf/server.xml from tomcat-hostpath3 (rw)
      /usr/local/tomcat/conf/ssl.crt from tomcat-hostpath1 (rw)
      /usr/local/tomcat/conf/ssl.key from tomcat-hostpath2 (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-8dhnk (ro)

这是我的 docker-compose.yml 文件:

---

version: '3.6'

networks:
  integration:

services:
  mysql:
    environment:
      MYSQL_USER: 'integrationdb'
      MYSQL_PASSWORD: 'password'
      MYSQL_ROOT_PASSWORD: 'password'
    image: db:poc
    networks:
    - integration
    ports:
    - '3306:3306'
    restart: always
    volumes:
       - ./dbdata:/var/lib/mysql
  tomcat:
    image: adapter:poc
    networks:
    - integration
    ports:
    - '8080:8080'
    - '8443:8443'
    restart: always
    volumes:
      - ./license.json:/run/secrets/rji_license.json
      - ./certificates/ssl.crt:/usr/local/tomcat/conf/ssl.crt
      - ./certificates/ssl.key:/usr/local/tomcat/conf/ssl.key
      - ./server.xml:/usr/local/tomcat/conf/server.xml

工具版本:

kompose: 1.21.0 (992df58d8)

docker: 19.03.9

kubectl:Major:"1", Minor:"18"

我认为我面临的挑战是在这种类型的卷或文件中，我不知道如何将它们迁移或转换为 kubernetes 并使 tomcat pod 正常运行。 有人可以帮我吗？

 volumes:
          - ./license.json:/run/secrets/rji_license.json
          - ./certificates/ssl.crt:/usr/local/tomcat/conf/ssl.crt
          - ./certificates/ssl.key:/usr/local/tomcat/conf/ssl.key
          - ./server.xml:/usr/local/tomcat/conf/server.xml

提前致谢。

Answer 1

当 Kompose 警告您时:

WARN Volume mount on the host "/usr/docker/adpater/license.json" isn't supported - ignoring path on the host

这意味着它无法将 docker-compose.yml 文件的此片段翻译为 Kubernetes 语法:

volumes:
    - ./license.json:/run/secrets/rji_license.json

在 native Kubernetes 中，您需要在 ConfigMap 或 Secret 对象中提供此内容，然后 mount the file into the pod 。您无法直接访问启动容器的系统上的内容。

您实际上无法在这里直接使用 Kubernetes YAML 文件。你可以运行 kompose convert生成框架文件，但随后您需要编辑这些文件以添加 ConfigMap、PersistentVolumeClaims(用于数据库存储)以及相关卷和挂载声明，然后运行 ​​kubectl apply -f 来实际上运行它们。我会将 Kubernetes YAML 文件 checkin 源代码管理，并与 Docker Compose 设置并行维护它们。