METRON-1965: Knox should work on a multi-node installation

[merrimanr]

Contributor Comments

This PR fixes a few bugs that are exposed when a Knox Gateway is not installed on the same host as Metron.

Changes Included

• The Metron Knox installed flag is now only written when Metron Knox is actually installed. Before it was being written when a Metron Client is installed, Metron Knox is enabled and Knox is not been present on that host yet.
• The Metron Client component now installs the various Metron scripts and binaries.
• The Knox host is now added to the Metron SSO whitelist.

Testing

This can be tested in full dev by just verifying Knox with Metron still works. It should also be tested in a multi-node environment where Knox and Metron are not colocated.

Other Considerations

I can't think of any reason we would not want the Metron Client component to install the various Metron packages but let me know if anyone disagrees.

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[anandsubbu]

+1 works as advertised.

Validated the changes on a 12-node setup, with the Knox gateway and metron being present on different nodes.
Verified that the swagger UI, alerts UI and mgmt UI comes up fine upon authenticating at the Knox SSO login page.

Thank you for the fix @merrimanr !