更新2016-03-02:从Docker 1.9.0开始,Docker已经命名了卷来取代数据容器。下面的答案,以及我链接的博客文章,在如何思考docker内部的数据方面仍然有价值,但考虑使用命名卷来实现下面描述的模式,而不是数据容器。
我认为解决这个问题的规范方法是使用仅数据容器。使用这种方法,对卷数据的所有访问都是通过使用数据容器中的-volumes-的容器进行的,因此主机uid/gid无关紧要。
For example, one use case given in the documentation is backing up a data volume. To do this another container is used to do the backup via tar, and it too uses -volumes-from in order to mount the volume. So I think the key point to grok is: rather than thinking about how to get access to the data on the host with the proper permissions, think about how to do whatever you need -- backups, browsing, etc. -- via another container. The containers themselves need to use consistent uid/gids, but they don't need to map to anything on the host, thereby remaining portable.
这对我来说也相对较新,但如果您有特定的用例,请随意评论,我将尝试扩展答案。
更新:对于注释中的给定用例,您可能有一个image some/graphite来运行graphite,并有一个image some/graphitedata作为数据容器。因此,忽略端口等,image some/graphitedata的Dockerfile是这样的:
FROM debian:jessie
# add our user and group first to make sure their IDs get assigned consistently, regardless of other deps added later
RUN groupadd -r graphite \
&& useradd -r -g graphite graphite
RUN mkdir -p /data/graphite \
&& chown -R graphite:graphite /data/graphite
VOLUME /data/graphite
USER graphite
CMD ["echo", "Data container for graphite"]
构建并创建数据容器:
docker build -t some/graphitedata Dockerfile
docker run --name graphitedata some/graphitedata
some/graphite Dockerfile也应该得到相同的uid/gid,因此它可能看起来像这样:
FROM debian:jessie
# add our user and group first to make sure their IDs get assigned consistently, regardless of other deps added later
RUN groupadd -r graphite \
&& useradd -r -g graphite graphite
# ... graphite installation ...
VOLUME /data/graphite
USER graphite
CMD ["/bin/graphite"]
它的运行方式如下:
docker run --volumes-from=graphitedata some/graphite
好了,现在我们得到了石墨容器和与正确的用户/组相关联的数据容器(注意,您也可以为数据容器重用some/graphite容器,在运行时覆盖entrypoing/cmd,但将它们作为单独的图像IMO更清楚)。
现在,假设您想要编辑数据文件夹中的内容。因此,与其将卷绑定挂载到主机并在那里编辑它,不如创建一个新容器来完成这项工作。我们叫它some/graphitetools。我们还可以创建适当的用户/组,就像some/graphite图像一样。
FROM debian:jessie
# add our user and group first to make sure their IDs get assigned consistently, regardless of other deps added later
RUN groupadd -r graphite \
&& useradd -r -g graphite graphite
VOLUME /data/graphite
USER graphite
CMD ["/bin/bash"]
你可以通过继承Dockerfile中的一些/graphite或一些/ graphitdata使其成为DRY,或者只是重用现有的一个映像(必要时重写entrypoint/cmd)而不是创建一个新的映像。
现在,你只需运行:
docker run -ti --rm --volumes-from=graphitedata some/graphitetools
然后是vi /data/graphite/whatever。txt。这可以很好地工作,因为所有容器都有相同的石墨用户和匹配的uid/gid。
因为从来没有从主机挂载/data/graphite,所以不关心主机uid/gid如何映射到graphite和graphitetools容器中定义的uid/gid。这些容器现在可以部署到任何主机上,并且它们将继续完美地工作。
这样做的好处是,graphitetools可以有各种有用的实用程序和脚本,现在您还可以以可移植的方式部署它们。
更新2:写完这个答案后,我决定写一篇关于这种方法的更完整的博客文章。我希望这能有所帮助。
UPDATE 3: I corrected this answer and added more specifics. It previously contained some incorrect assumptions about ownership and perms -- the ownership is usually assigned at volume creation time i.e. in the data container, because that is when the volume is created. See this blog. This is not a requirement though -- you can just use the data container as a "reference/handle" and set the ownership/perms in another container via chown in an entrypoint, which ends with gosu to run the command as the correct user. If anyone is interested in this approach, please comment and I can provide links to a sample using this approach.