Use NSS_WRAPPER_PASSWD instead of /etc/passwd as in spark-operator image entrypoint.sh

[Aakcht]

Purpose of this PR

Currently spark-operator entrypoint.sh has this logic. It is the same logic as in entrypoint.sh of old spark images. It is intended for openshift and modifies /etc/passwd. It was working in the past, because in the older base spark images permissions for /etc/passwd were modified.

New spark images do not modify permissions of /etc/passwd. Therefore this entrypoint.sh logic does not work currently and when running spark-operator under random user spark-application submissions fails with the following error:

 org.apache.hadoop.security.KerberosAuthException: failure to login: javax.security.auth.login.LoginException: java.lang.NullPointerException: invalid null input: name

This PR changes this logic to the same logic as in newer spark images.

Proposed changes:

• Modify entrypoint.sh logic of working with /etc/passwd and NSS_WRAPPER_PASSWD based on new spark image.

Change Category

• Bugfix (non-breaking change which fixes an issue)
• Feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that could affect existing functionality)
• Documentation update

Rationale

Checklist

• I have conducted a self-review of my own code.
• I have updated documentation accordingly.
• I have added tests that prove my changes are effective or that my feature works.
• Existing unit tests pass locally with my changes.

Additional Notes

I validated this PR by adding new entrypoint.sh to spark-operator docker image and checked that spark-operator can now submit applications when running under random user.

[google-oss-prow]

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[Aakcht]

Hi, @ChenYi015 @ImpSy @jacobsalway , any chance for reviewing this PR?