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https://issues.apache.org/jira/browse/FLINK-29572?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17618407#comment-17618407
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Kevin Li commented on FLINK-29572:
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1. It is called service mesh, basically all ingress/egress traffic are captured
by proxy and proxies are connected as service mesh so that apps are transparent
for service discovery and many more.
https://istio.io/latest/docs/ops/deployment/architecture/
2. With service mesh proxy deployed, TM can connect JM using loopback address.
If this works, TM will report its address as 127.0.0.1:6223. JM can RPC this
address as well. But as soon as you have multiple TMs, all of them will report
their address as 127.0.0.1:6223. Obviously only one will succeed. This result
JM can only connect with one TM, which is the one got success.
3. Capturing loopback traffic and forward to remote is how proxy working.
Disable this will make proxy useless. Pls check the link in No.1.
> Flink Task Manager skip loopback interface for resource manager registration
> ----------------------------------------------------------------------------
>
> Key: FLINK-29572
> URL: https://issues.apache.org/jira/browse/FLINK-29572
> Project: Flink
> Issue Type: Bug
> Components: API / Core
> Affects Versions: 1.15.2
> Environment: Flink 1.15.2
> Kubernetes with Istio Proxy
> Reporter: Kevin Li
> Priority: Major
>
> Currently Flink Task Manager use different local interface to bind to connect
> to Resource Manager. First one is Loopback interface. Normally if Job Manager
> is running on remote host/container, using loopback interface to connect will
> fail and it will pick up correct IP address.
> However, if Task Manager is running with some proxy, loopback interface can
> connect to remote host as well. This will result 127.0.0.1 reported to
> Resource Manager during registration, even Job Manager/Resource Manager runs
> on remote host, and problem will happen. For us, only one Task Manager can
> register in this case.
> I suggest adding configuration to skip Loopback interface check if we know
> Job/Resource Manager is running on remote host/container.
>
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