Manually migrate Nginx visualizations to lens in current Kibana version 8.5.0 itself.

Preparation of data for testing

• Use sample_event.json / setup live instance using docker / mock data using mock server to populate dashboards

Migration stats

Dashboard : [Metrics Nginx] Overview

• Migrate 9 visualization to the lens.
  • [O11y][Nginx] Migrate [Metrics Nginx] Overview dashboard visualizations to lens in kibana 8.5.0 #5780

Dashboard : [Logs Nginx] Access and error logs

• Migrate 2 visualization to the lens.
  • [O11y][Nginx] Migrate [Logs Nginx] Access and error logs dashboard visualizations to lens in kibana 8.5.0 #5782

Dashboard : [Logs Nginx] Overview

• Migrate 7 visualization to the lens.
  • [O11y][Nginx] Migrate [Logs Nginx] Overview dashboard visualizations to lens in kibana 8.5.0  #5781

Verification and Validation

• Verification of functionality remains the same after migration in Kibana
• Verification of data count of after-migrated visualization with before-migrated visualization in Kibana
• Verification of Dashboard are not distorted in supported Kibana version (8.5.0)

Note:
In the Response codes over time [Logs Nginx] we faced below two issues:

1. Lens doesn't have a gradient color palette.
   Solution: Set the color palette to status color palette because the values are defined by response status codes.
2. We are unable to set http.response.status_code: [200 TO 299] filters due to number_format_exception.
   Solution: To overcome this issue we have set the filter as http.response.status_code >= 200 and http.response.status_code<= 299.

Issues Identified

• [O11y][Nginx] Add Y-axis labels and Readjust column width in saved search of Nginx dashboards #5795