How to update Kong configuration that is hard coded in `/usr/local/share/lua/5.1/kong/templates/nginx_kong.lua` when using Helm charts

There is one or more nginx configuration options which are hard coded in the /usr/local/share/lua/5.1/kong/templates/nginx_kong.lua file that propagate to nginx-kong.conf in the kong <prefix> directory, and determine the nginx configuration, and we need to override those values. Using a custom nginx template would be a way to address this, but with the Kong Helm charts this does not seem to be straight forward. What is a good way to override the /usr/local/share/lua/5.1/kong/templates/nginx_kong.lua file when using Kong Helm charts?

As documented with the Kong Helm charts you can add configMap to a custom volume with a custom mount point using the userDefinedVolumes, and userDefinedVolumeMounts elements under the deployment property of your values.yaml file.

To replace /usr/local/share/lua/5.1/kong/templates/nginx_kong.lua you would need to:

1. Create a configMap using something like the following command:

   kubectl -n <yournamespace> create configmap nginx-kong-lua --from-file=nginx_kong.lua

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2. Change the values.yaml to use that configMap as in this configuration:

   deployment:
     kong:
       enabled: true
       daemonset: false
     userDefinedVolumes:
     - name: "nginx-kong-lua"
       configMap:
         name: nginx-kong-lua
     userDefinedVolumeMounts:
     - name: "nginx-kong-lua"
       mountPath: "/usr/local/share/lua/5.1/kong/templates/nginx_kong.lua"
       subPath: "nginx_kong.lua"
   
   image:
     repository: kong/kong-gateway
   ...

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WARNING: Before upgrading Kong (even to a new minor version), you MUST make sure that the /usr/local/share/lua/5.1/kong/templates/nginx_kong.lua has not changed or if it has, use the new version with the required changes on your side.