[FLINK-13749] Make Flink client respect classloading policy

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 1.8.3, 1.9.2, 1.10.0
• Component/s: Command Line Client, Runtime / REST
• Labels: pull-request-available

Release Note

The Flink client now also respects the configured classloading policy, i.e. parent-first or child-first classloading. Previously only cluster components such as the job manager or task manager supported this setting.

This does mean that users might get different behaviour in their programs, in which case they should configure the classloading policy explicity to use parent-first classloading, which was the previous (hard-coded) behaviour.

• Assignee: Paul Lin
• Reporter: Paul Lin
• Created: 16/Aug/19 10:04
• Updated: 29/Jan/20 14:25
• Resolved: 25/Nov/19 11:20

Description

Currently, Flink client does not respect the classloading policy and uses hardcoded parent-first classloader, while the other components like jobmanager and taskmanager use child-first classloader by default and respect the classloading options. This makes the client more likely to have dependency conflicts, especially after we removed the convenient hadoop binaries (so users need to add hadoop classpath in the client classpath).

So I propose to make Flink client's (including cli and rest handler) classloading behavior aligned with the other components.

Issue Links

• is duplicated by: FLINK-14037 Deserializing the input/output formats failed: unread block data
• is duplicated by: FLINK-14575 Wrong (parent-first) class loader during serialization while submitting jobs
• is duplicated by: FLINK-14598 The use of FlinkUserCodeClassLoaders is unreasonable.
• links to: GitHub Pull Request #10113