Treat IP Address as an optional parameter

[ctyano]

Description

IP addresses in X.509 Subject Alternative Names is an optional attribute in Athenz X.509 identity certificate.
Users shall set an empty string to POD_IP environment variable to remove IP address from a CSR.
If the IP address is not set in the CSR, ZTS will skip verifying the client IP address to match the SANs IP. (e.g. InstanceZTSProvider)

Assignees

• Assignees is set

Type of changes

• Apply one or more labels of the following that fits:
  • bug: Bug fix
  • dependencies: Dependency upgrades
  • documentation: Documentation changes
  • enhancement: New Feature
  • good first issue: First contribution
  • logging: Log changes
  • refactor: Refactoring (no functional changes, no api changes)

Flags

• Breaks backward compatibility
• Requires a documentation update
• Has untestable code

---

Checklist

• Followed the guidelines in the CONTRIBUTING document
• Added prefix [skip ci]/[ci skip]/[no ci]/[skip actions]/[actions skip] in the PR title if necessary
• Tested and linted the code
• Commented the code
• Made corresponding changes to the documentation

Checklist for maintainer

• Use Squash and merge
• Double-confirm the merge message has prefix [skip ci]/[ci skip]/[no ci]/[skip actions]/[actions skip]
• Delete the branch after merge

[mlajkim]

Please modify the athenz-sia.env file too.

• Modify: https://github.com/AthenZ/k8s-athenz-sia/blob/main/athenz-sia.env#L119

[mlajkim]

@ctyano Do you think we should merge this before the release of v3.2.0?

[mlajkim]

This requires operation check just in case in k8s platform.
TODOs:
-[x] Operation done by @mlajkim

I won't do it as I wrote this with expectation of including this PR in v3.2.0.

[mlajkim]

This won't be included in v3.2.0 release.