如何在 kubernetes 部署时覆盖文件？

Question

我正在尝试在 kubernetes 中部署 Diffusion 映像，我需要在部署时覆盖其中一个 Diffusion 配置文件。

实际上它是一个SystemAuthentication.store 文件，默认凭据位于/opt/Diffusion6.0.3_01/etc/。我正在秘密存储新文件并将其挂载到etc/test/，这可以在下面的部署文件中看到。

template:
metadata:
  labels:
    run: diffusion
spec:
  serviceAccountName: diffusion-role
  volumes:
  - name: diffusion-secrets
    secret:
      secretName: diffusion-license
  - name: ssl-cert
    secret:
      secretName: ssl-certificate
  - name: system-authentication
    secret:
      secretName: system-authentication-store
  containers:
  - image: pushtechnology/diffusion:6.0.3
    imagePullPolicy: IfNotPresent
    name: diffusion
    ports:
    - containerPort: 8080
      protocol: TCP
    - containerPort: 8443
      protocol: TCP
    volumeMounts:
    - name: diffusion-secrets
      mountPath: /etc/diffusion-secrets
      readOnly: true
    - name: ssl-cert
      mountPath: /etc/test/
      readOnly: true
    - name: system-authentication
      mountPath: /etc/test/
    command: [ "/bin/sh", "-c", "cp etc/test/SystemAuthentication.store /opt/DIffusion6.0.3_01" ]

当我部署此映像时，pod 失败了

Events:
Type     Reason                 Age              From                                   Message
----     ------                 ----             ----                               -------
Normal   Scheduled              2m               default-scheduler                  Successfully assigned diffusion-db6d6df7b-f5tp4 to timmy.pushtechnology.com
Normal   SuccessfulMountVolume  2m               kubelet, timmy.pushtechnology.com  MountVolume.SetUp succeeded for volume "diffusion-role-token-n59ds"
Normal   SuccessfulMountVolume  2m               kubelet, timmy.pushtechnology.com  MountVolume.SetUp succeeded for volume "ssl-cert"
Normal   SuccessfulMountVolume  2m               kubelet, timmy.pushtechnology.com  MountVolume.SetUp succeeded for volume "system-authentication"
Normal   SuccessfulMountVolume  2m               kubelet, timmy.pushtechnology.com  MountVolume.SetUp succeeded for volume "diffusion-secrets"
Normal   Killing                1m (x2 over 1m)  kubelet, timmy.pushtechnology.com  Killing container with id docker://diffusion:FailedPostStartHook
Warning  BackOff                1m (x2 over 1m)  kubelet, timmy.pushtechnology.com  Back-off restarting failed container
Normal   Pulled                 1m (x3 over 2m)  kubelet, timmy.pushtechnology.com  Container image "pushtechnology/diffusion:6.0.3" already present on machine
Normal   Created                1m (x3 over 1m)  kubelet, timmy.pushtechnology.com  Created container
Normal   Started                1m (x3 over 1m)  kubelet, timmy.pushtechnology.com  Started container
Warning  FailedPostStartHook    1m (x3 over 1m)  kubelet, timmy.pushtechnology.com  
Warning  FailedSync             1m (x5 over 1m)  kubelet, timmy.pushtechnology.com  Error syncing pod

我也尝试过这里描述的工作：https://github.com/kubernetes/kubernetes/issues/19764#issuecomment-269879587

结果相同。

Answer 1

您用cp etc/test/SystemAuthentication.store /opt/DIffusion6.0.3_01 覆盖了容器命令，这是一个完成后退出的命令。 Kubernetes 认为这是一个失败。

您需要将其替换为cp etc/test/SystemAuthentication.store /opt/DIffusion6.0.3_01 && /path/to/original/binary 之类的内容，其中最后一个命令是映像在不覆盖命令的情况下启动的命令。这取决于你的形象。

Answer 2

我认为@svenwtl answer 可能是正确的，但我使用的图像的Dockerfile 有一些复杂的结构，我不知道如何在部署文件中使用。 对我有用的修复（经过长时间的尝试/失败循环）是实际使用容器生命周期钩子：

    volumeMounts:
    - name: diffusion-secrets
      mountPath: /etc/diffusion-secrets
      readOnly: true
    - name: ssl-cert
      mountPath: /etc/test/
      readOnly: true
    - name: system-authentication
      mountPath: /etc/test1/
    lifecycle:
      postStart:
        exec:
          command: [ "/bin/sh", "-c", "cp -f /etc/test1/SystemAuthentication.store /opt/Diffusion6.0.3_01/etc/" ]

我还在不同的文件夹 /etc/test1 中安装了 SystemAuthentication，但我认为这不是修复的一部分。