RANGER-5373: Docker setup updated to run KDC and create keytabs for service accounts

[mneethiraj]

What changes were proposed in this pull request?

Introduced Dockerfile.ranger-kdc to deploy a Kerberos KDC; introduced script create_keytab.sh which can be used by services to create Kerberos principals and keytabs for their use.

How was this patch tested?

Brought up Ranger container using docker compose along with -f docker-compose.ranger-kdc.yml and confirmed that each service created service principals and keytabs need for the service.

[Copilot]

Pull Request Overview

This PR introduces Kerberos support to the Ranger Docker setup by adding a KDC container and integrating Kerberos principal/keytab creation across all Ranger services.

Key changes:

• Added a new Kerberos KDC service with Docker support and configuration files
• Integrated Kerberos client tools and keytab creation capability into all service containers
• Updated configuration files to include Kerberos settings for Ranger admin across different database backends

Reviewed Changes

Copilot reviewed 41 out of 41 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
Dockerfile.ranger-kdc	New Dockerfile defining the Kerberos KDC container
config/kdc/*	KDC configuration files (krb5.conf, kdc.conf, kadm5.acl) and scripts (entrypoint.sh, create_keytab.sh)
docker-compose.ranger-kdc.yml	New compose file to deploy the KDC service
scripts/ranger*.sh	Updated service startup scripts to create Kerberos principals and keytabs when Kerberos is enabled
Dockerfile.ranger*	Modified to install krb5-user package and copy Kerberos configuration files
docker-compose.ranger*.yml	Updated to pass KERBEROS_ENABLED environment variable and build argument
scripts/ranger-admin-install-*.properties	Added Kerberos configuration properties for different database backends
.env	Added Kerberos-related environment variables

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[Copilot]

Hard-coded credentials in the script create a security vulnerability. These credentials should be passed as environment variables or parameters instead of being embedded in the script.