[FLINK-14991] Export `FLINK_HOME` environment variable to all the entrypoint

• Type: Improvement
• Status: Reopened
• Priority: Not a Priority
• Resolution: Unresolved
• Component/s: Command Line Client, Deployment / Scripts
• Assignee: Unassigned
• Reporter: Guowei Ma
• Created: 29/Nov/19 10:36
• Updated: 29/Jul/21 07:37

Description

 Currently, Flink depends on 6 types of files: configuration files, system jars files, script files、library jar files, plugin jar files, and user jars files. These files are in different directories. 

Flink exports 5 environment variables to locate these different type files: `FLINK_CONF_DIR`,`FLINK_LIB_DIR`,`FLINK_OPT_DIR`,`FLINK_PLUGIN_DIR`,`FLINK_BIN_DIR`.

It is not a good style that exports an environment variable for every type of file.

So this jira proposes to export the `FLINK_HOME` environment variable to all the entrypoint. Derive the directory of the different type files from the `FLINK_HOME` environment variable and every type file has a fixed directory name.

 This also has another benefit that the method implies the directory structure is the same in all the situations.