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https://issues.apache.org/jira/browse/YARN-4266?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15899828#comment-15899828
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Eric Badger commented on YARN-4266:
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[~tangzhankun], thanks for pointing that out. I hadn't seen that conversation.
It seems that the major issue with using --user=UID:GID is that there is no
username. But is there any reason that we can't just add in an environment
variable to the docker run command that is set to the username and then run a
usermod to change the username of the associated UID? Usernames are just
cosmetic and everything is done via UIDs, so I don't think it makes sense to
run the docker container based on a username.
Something like:
{{docker run --user=2000 -e USERNAME=\*username crafted in code\*}}
And then in the container startup command (with the container running as root):
{{usermod -l $USERNAME $(getent passwd "1001" | cut -d: -f1) && su $USERNAME}}
There are probably more efficient ways to do this, but this is just a general
idea and proof of concept.
The main problem that I can see with this method is if there is already a user
in the image associated with the UID of the user on the host. In that case, we
would need to remap the UID of the user in the image to something different
before we could do the usermod (or else we would have potential permissions
issues inside the container). However, this would also be easy to do.
[~sidharta-s], [~templedf], [~vvasudev], [~zyluo], you were all very active on
YARN-5360. Do you have any thoughts on the approach above given my explanation?
> Allow whitelisted users to disable user re-mapping/squashing when launching
> docker containers
> ---------------------------------------------------------------------------------------------
>
> Key: YARN-4266
> URL: https://issues.apache.org/jira/browse/YARN-4266
> Project: Hadoop YARN
> Issue Type: Sub-task
> Components: yarn
> Reporter: Sidharta Seethana
> Assignee: Zhankun Tang
> Attachments: YARN-4266.001.patch,
> YARN-4266_Allow_whitelisted_users_to_disable_user_re-mapping.pdf,
> YARN-4266_Allow_whitelisted_users_to_disable_user_re-mapping_v2.pdf,
> YARN-4266_Allow_whitelisted_users_to_disable_user_re-mapping_v3.pdf,
> YARN-4266-branch-2.8.001.patch
>
>
> Docker provides a mechanism (the --user switch) that enables us to specify
> the user the container processes should run as. We use this mechanism today
> when launching docker containers . In non-secure mode, we run the docker
> container based on
> `yarn.nodemanager.linux-container-executor.nonsecure-mode.local-user` and in
> secure mode, as the submitting user. However, this mechanism breaks down with
> a large number of 'pre-created' images which don't necessarily have the users
> available within the image. Examples of such images include shared images
> that need to be used by multiple users. We need a way in which we can allow a
> pre-defined set of users to run containers based on existing images, without
> using the --user switch. There are some implications of disabling this user
> squashing that we'll need to work through : log aggregation, artifact
> deletion etc.,
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