jvm settings from bootstrap.conf vs from outside

[#1]

For nifi, we have jvm options in bootstrap.conf:

java.arg.2=-Xms512m
java.arg.3=-Xmx512m

Then we also have env variables(got to know on google search,not from official documentation) that can be set from outside(like from kubernetes config yaml):

NIFI_JVM_HEAP_INIT
NIFI_JVM_HEAP_MAX

What's the connection between these 2 sets of properties?

[#2]

java.arg.2 and java.arg.3 in bootstrap.conf: These are the traditional way of setting JVM arguments within the NiFi configuration file itself. They translate to:

java.arg.2=-Xms512m: This sets the initial heap size of the NiFi JVM to 512 megabytes (m).
java.arg.3=-Xmx512m: This sets the maximum heap size of the NiFi JVM to 512 megabytes (m).
NIFI_JVM_HEAP_INIT and NIFI_JVM_HEAP_MAX environment variables: These are environment variables that allow you to configure the JVM heap size externally. This is particularly useful when deploying NiFi in containerized environments

If both java.arg.2 / java.arg.3 and NIFI_JVM_HEAP_INIT / NIFI_JVM_HEAP_MAX are defined, the environment variables take precedence. This means the values set in the environment variables will be used to configure the JVM heap size.

@manishg