如何将纯数据卷从一台主机移植到另一台主机? [英] How to port data-only volumes from one host to another?

问题描述

如关于使用卷的Docker文档中所述，有一个所谓的概念data-only 容器，它提供了一个可以挂载到多个其他容器中的卷，无论该 data-only 容器是否实际运行.

As described in the Docker documentation on Working with Volumes there is the concept of so-called data-only containers, which provide a volume that can be mounted into multiple other containers, no matter whether the data-only container is actually running or not.

基本上，这听起来很棒.但有一件事我不明白.

Basically, this sounds awesome. But there is one thing I do not understand.

这些卷(出于可移植性的原因，它们不会显式映射到主机上的文件夹，如文档所述)由 Docker 在主机上的某个内部文件夹中创建和管理(/var/docker/volumes/...).

These volumes (which do not explicitly map to a folder on the host for portability reasons, as the documentation states) are created and managed by Docker in some internal folder on the host (/var/docker/volumes/…).

假设我使用了这样一个卷，然后我需要将它从一台主机迁移到另一台主机 - 我该如何移植该卷?AFAICS 它有一个唯一的 ID - 我可以直接将卷及其相应的仅数据容器复制到新主机吗?如何找出要复制的文件?或者是否有一些我还没有发现的内置于 Docker 的支持?

Supposed I use such a volume, and then I need to migrate it from one host to another - how do I port the volume? AFAICS it has a unique ID - can I just go and copy the volume and its according data-only container to a new host? How do I find out which files to copy? Or is there some support built-in to Docker that I did not discover yet?

推荐答案

官方答案在 "备份、恢复或迁移数据卷":

备份:

sudo docker run --rm --volumes-from DATA -v $(pwd):/backup busybox tar cvf /backup/backup.tar /data

• --rm:容器退出时移除
• --volumes-from DATA:附加到DATA容器共享的volumes
• -v $(pwd):/backup:绑定挂载当前目录到容器中；将tar文件写入
• busybox:一个简单的小图像 - 适合快速维护
• tar cvf/backup/backup.tar/data:创建/data目录下所有文件的解压tar文件
• --rm: remove the container when it exits
• --volumes-from DATA: attach to the volumes shared by the DATA container
• -v $(pwd):/backup: bind mount the current directory into the container; to write the tar file to
• busybox: a small simpler image - good for quick maintenance
• tar cvf /backup/backup.tar /data: creates an uncompressed tar file of all the files in the /data directory

恢复:

# create a new data container
$ sudo docker create -v /data --name DATA2 busybox true
# untar the backup files into the new container᾿s data volume
$ sudo docker run --rm --volumes-from DATA2 -v $(pwd):/backup busybox tar xvf /backup/backup.tar
data/
data/sven.txt
# compare to the original container
$ sudo docker run --rm --volumes-from DATA -v `pwd`:/backup busybox ls /data
sven.txt

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