docker - 为什么Docker中会出现 "none"镜像以及我们如何避免它

Question

当我运行docker-compose build时命令在 Docker 中重建图像，因为我更改了 Dockerfile 中的某些内容，有时我得到“无”图像标签。我们怎样才能避免这个事实呢？我想重建图像，但无图像不应出现。

REPOSITORY  TAG            IMAGE ID            CREATED             SIZE
magento2    latest         b4dce4dcbd4f        16 hours ago        516MB
<none>      <none>         b4ffce2bf91e        16 hours ago        519MB
<none>      <none>         a1aedb60c82a        17 hours ago        516MB
<none>      <none>         ec9a14ae856c        20 hours ago        519MB
<none>      <none>         ef8eba6874cc        23 hours ago        516MB
<none>      <none>         0e53a8b8c303        23 hours ago        516MB
php         7.1-apache     93e6fb4b13e1        3 weeks ago         369MB
mysql       5.6.39         079344ce5ebd        7 months ago        256MB

Answer 1

以下是 What are Docker <none>:<none> images? 的一些部分

The Good <none>:<none>

These are intermediate images and can be seen using docker images -a. They don't result into a disk space problem but it is definitely a screen "real estate" problem. Since all these <none>:<none> images can be quite confusing as what they signify.

The Bad <none>:<none>

These images are the dangling ones, which can cause disk space problems. These <none>:<none> images are being listed as part of docker images and need to be pruned.

(a dangling file system layer in Docker is something that is unused and is not being referenced by any images. Hence we need a mechanism for Docker to clear these dangling images)

所以，

• 如果您的案件与dangling有关图像，可以删除它们:

   docker rmi $(docker images -f "dangling=true" -q)
  

  还有docker image prune的选项但客户端和守护进程 API 必须至少为 v1.25使用此命令。

• 如果您的案件与intermediate有关图像，保留它们就可以了，其他图像指向它们的引用。

相关文档:

• docker rmi
• docker image rm
• docker image prune