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https://issues.apache.org/jira/browse/YARN-8777?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16620815#comment-16620815
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Eric Yang commented on YARN-8777:
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[~ebadger] {quote}Opening up a bash session allows the user to then execute
whatever commands they want to anyway. Am I missing something here?{quote}
The difference is causing harm to container executor's memory prior to docker
exec -it bash is launched. The argv is constructed and checked in
container-executor and forward to docker exec. If it is fixed number of
arguments, container-executor logic has little chance of getting it wrong. If
the number is dynamic, and passing args exceeding docker's parameter parser
have unpredictable result, and other corner case such as:
{code}
cmd="mongo --eval 'rs.isMaster()"
docker exec d886e775dfad "$cmd"
{code}
Docker will look for binary named "mongo -eval 'rs.isMaster()'" instead of
mongo, and the rest of parameters to monogo. Shell expansion corner cases will
not handle gracefully and cause people to scratch their heads. It is entirely
possible to use ProcessBuilder and launch container-executor to run docker
exec, and send unix command to be executed. The added bash gives less
experienced developers ability to script their execution without thinking about
parameter passing overflow and shell expansion. The command are ran inside the
container without leaking to problems to container-executor level. Hope this
explains the choice of parameter passing for this use case.
> Container Executor C binary change to execute interactive docker command
> ------------------------------------------------------------------------
>
> Key: YARN-8777
> URL: https://issues.apache.org/jira/browse/YARN-8777
> Project: Hadoop YARN
> Issue Type: Sub-task
> Reporter: Zian Chen
> Assignee: Eric Yang
> Priority: Major
> Labels: Docker
> Attachments: YARN-8777.001.patch
>
>
> Since Container Executor provides Container execution using the native
> container-executor binary, we also need to make changes to accept new
> “dockerExec” method to invoke the corresponding native function to execute
> docker exec command to the running container.
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