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https://issues.apache.org/jira/browse/FLINK-15871?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17060620#comment-17060620
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Canbin Zheng edited comment on FLINK-15871 at 3/17/20, 4:20 AM:
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{color:#0e101a}Hi, {color}[{color:#4a6ee0}Yang
Wang{color}|https://issues.apache.org/jira/secure/ViewProfile.jspa?name=fly_in_gis]{color:#0e101a}!{color}
{color:#0e101a}The init container is a basic design since we need it to
download dependencies in the per job or the so-called application mode, and the
users do not have to do much on using the init container. So it's reasonable
that we introduce this feature for the codebase.{color}
{color:#0e101a}As to the sidecar container, I think it is an advanced feature
instead of a basic one. We'd better not introduce explicit support for it and
leave the users to enable such a feature via the pod template.{color}
{color:#0e101a}For the usage scenarios you mentioned for the sidecar container,
I would like to share some information:{color}
{color:#0e101a}> Collect logs{color}
{color:#0e101a}Usually, we do not use sidecar containers to collect logs to
avoid efficiency issues. The more general way is to start a dedicated service
on the host to collect all the logs for all the Pods located on the same host.
The latter solution improves efficiency since we do not start a dedicated
sidecar process for every pod.{color}
{color:#0e101a}> With debugging image which contains lots of tools and helps to
debug the network problems{color}
{color:#0e101a}We could add tools into the basic image used by the main
Container of the JM and TMs.{color}
{color:#0e101a} {color}
{color:#0e101a}With the rapid development of Kubernetes, we could add many
features into the module of flink-kubernetes. However, in the long run, I
propose that we should narrow the config options and only introduce the basic
features, meanwhile, let the users enable some advanced features via pod
template. This could help the community to reduce maintenance work on this
module.{color}
{color:#0e101a} {color}
{color:#0e101a} {color}
{color:#0e101a} {color}
was (Author: felixzheng):
{color:#0e101a}Hi, {color}[{color:#4a6ee0}Yang
Wang{color}|https://issues.apache.org/jira/secure/ViewProfile.jspa?name=fly_in_gis]{color:#0e101a}!{color}
{color:#0e101a}The init container is a basic design since we need it to
download dependencies in the per job or the so-called application mode, and the
users do not have to do much on using the init container. So it's reasonable
that we introduce this feature for the codebase.{color}
{color:#0e101a}As to the sidecar container, I think it is an advanced feature
instead of a basic one. We'd better not introduce explicit support for it and
leave the users to enable such a feature via the pod template.{color}
{color:#0e101a}For the usage scenarios you mentioned for the sidecar container,
I would like to share some information:{color}
{color:#0e101a}> Collect logs{color}
{color:#0e101a}Usually, we do not use sidecar containers to collect logs to
avoid efficiency issues. The more general way is to start a dedicated service
on the host to collect all the logs for all the Pods located on the same host.
The latter solution improves efficiency since we do not start a dedicated
sidecar process for every pod.{color}
{color:#0e101a}> With debugging image which contains lots of tools and helps to
debug the network problems{color}
{color:#0e101a}We could add tools into the basic image used by the main
Container of the JM and TMs.{color}
{color:#0e101a} {color}
{color:#0e101a}With the rapid development of Kubernetes, we could add many
features into the module of flink-kubernetes. However, in the long run, I
propose that we should narrow the config options and only introduce the basic
features, meanwhile, let the users enable some advanced features via pod
template. This could help the community to reduce maintenance work on this
module.{color}
{color:#0e101a} {color}
{color:#0e101a} {color}
{color:#0e101a} {color}
> Support to start sidecar container
> ----------------------------------
>
> Key: FLINK-15871
> URL: https://issues.apache.org/jira/browse/FLINK-15871
> Project: Flink
> Issue Type: Sub-task
> Components: Deployment / Kubernetes
> Affects Versions: 1.10.0
> Reporter: Yang Wang
> Priority: Major
> Fix For: 1.11.0
>
>
> >> How does sidecar container work?
> A sidecar container is running beside the Jobmanager and TaskManager
> container. It could be used to collect log or debug some problems. For
> example, when we configure the sidecar container to fluentd and share the
> TaskManager log with volume, then it could be used to upload the logs to
> HDFS, elastic search, etc. Also we could start a sidecar container with
> debugging image which contains lots of tools and help to debug the network
> problems.
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