Add DNS resolver and routes to node addition YAML example

[msarage-ux]

Summary

This PR fixes the incomplete nodes-config.yaml example in the node addition guide by adding required DNS resolver and routes configuration, and documents the double CSR approval requirement.

Issue

Fixes: OSDOCS-15544

Problem

The current nodes-config.yaml example in the OCP 4.17 node addition guide is missing critical network configuration:

1. Missing DNS configuration - No dns-resolver section with DNS server and search domain
2. Missing routes configuration - No default gateway routes
3. Unclear CSR approval process - Documentation doesn't mention that CSRs must be approved twice per node

These omissions caused node join failures in production environments. Users following the documentation example would create incomplete network configurations.

Solution

Updated the example YAML configuration to include:

DNS Resolver Configuration

dns-resolver:
  config:
    server:
      - 192.168.122.1
    search:
      - example.com

Routes Configuration

routes:
  config:
    - destination: 0.0.0.0/0
      next-hop-address: 192.168.122.1
      next-hop-interface: eth0

CSR Approval Documentation

Added an IMPORTANT note explaining:

• Each node requires two CSR approvals
• First CSR is for the kubelet client certificate
• Second CSR is for the kubelet serving certificate
• Both must be approved for successful node addition

Changes

• modules/adding-node-iso-yaml.adoc:
  • Added dns-resolver section to both worker examples
  • Added routes section to both worker examples
  • Added IMPORTANT admonition block documenting double CSR approval requirement

Impact

• ✅ Provides complete, working YAML example
• ✅ Prevents node join failures due to missing DNS configuration
• ✅ Clarifies CSR approval process
• ✅ Matches real-world production configurations
• ✅ Improves user success rate when adding nodes

Testing

• Documentation-only changes
• YAML syntax verified
• AsciiDoc formatting confirmed
• Based on verified working configuration from field deployment

References

• Jira: OSDOCS-15544
• Affected Documentation: https://docs.redhat.com/en/documentation/openshift_container_platform/4.17/html-single/nodes/index#adding-node-iso

🤖 Generated with Claude Code

[openshift-ci]

Hi @msarage-ux. Thanks for your PR.

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