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https://issues.apache.org/jira/browse/SPARK-23153?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16640086#comment-16640086
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Stavros Kontopoulos edited comment on SPARK-23153 at 10/5/18 5:13 PM:
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The question is what can you do when you dont have a distributed cache like in
the yarn case. Do we need to upload artifacts in the first place or fetch them
remotely (eg. cluster mode)? Mesos has the same issue AFAIK.
Having pre-populated PVs is not different to me as a mechanism compared to
images since no uploading takes place from the submission side to the driver
via spark submit. Someone has to approve PVs contents too as well when it comes
to security. If we can do it in Spark without going down the path of using K8s
constructs like init containers without performance issues then we should be
ok. Even now, if not mistaken, executors on k8s fetch jars from the driver when
they update their dependencies and that contradicts the third point.
But what do you do when you need driver HA (many people use that)? Then you
need check-pointing and you need to store artifacts to some storage like PVs or
custom images or hdfs (distributed storage in general). If we omit the last two
then the only option I see is PVs where client artifacts are uploaded via the
PVs thing. On the other hand PVs can be hard to manage in general from an
administration perspective and that breaks a bit the UX (users are lazy, they
would say just let me point to my artifact from the spark submit side) .
On the other hand you cant really expose the driver's internal file server
because it is not persistent unless you make it store its artifacts to a PV
instead of the container tmp dir. In that scenario we could upload artifacts to
the driver directly and allow restarts.
was (Author: skonto):
The question is what can you do when you dont have a distributed cache like in
the yarn case. Do we need to upload artifacts in the first place or fetch them
remotely (eg. cluster mode)? Mesos has the same issue AFAIK.
Having pre-populated PVs is not different to me as a mechanism compared to
images since no uploading takes place from the submission side to the driver
via spark submit. Someone has to approve PVs contents too as well when it comes
to security. If we can do it in Spark without going down the path of using K8s
constructs like init containers without performance issues then we should be
ok. Even now, if not mistaken, executors on k8s fetch jars from the driver when
they update their dependencies and that contradicts the third point.
But what do you do when you need driver HA (many people use that)? Then you
need check-pointing and you need to store artifacts to some storage like PVs or
custom images or hdfs (distributed storage in general). If we omit the last two
then the only option I see is PVs where client artifacts are uploaded via the
PVs thing. On the other hand PVs can be hard to manage in general from an
administration perspective and that breaks a bit the UX (users are lazy, they
would say just let me point to my artifact from the spark submit side) .
On the other hand you cant really expose the driver's internal file server
because it is not persistent unless you make it store its artifacts to a PV. In
that scenario we could upload artifacts to the driver directly.
> Support application dependencies in submission client's local file system
> -------------------------------------------------------------------------
>
> Key: SPARK-23153
> URL: https://issues.apache.org/jira/browse/SPARK-23153
> Project: Spark
> Issue Type: Improvement
> Components: Kubernetes
> Affects Versions: 2.4.0
> Reporter: Yinan Li
> Priority: Major
>
> Currently local dependencies are not supported with Spark on K8S i.e. if the
> user has code or dependencies only on the client where they run
> {{spark-submit}} then the current implementation has no way to make those
> visible to the Spark application running inside the K8S pods that get
> launched. This limits users to only running applications where the code and
> dependencies are either baked into the Docker images used or where those are
> available via some external and globally accessible file system e.g. HDFS
> which are not viable options for many users and environments
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