Last tested: Apr 18, 2021
Default API port on GCP/Azure hosted instances is
443 - it’s no longer accessed via hitting port 19999. A layer 7 load balancer will redirect it internally to that port. Note that AWS-hosted k8s (EKS) has port 19999 set up to forward to 443.
K8s can only route requests by domain name and URL paths - NOT by port number.
Make sure that when you are making API requests, that the url always begins with /api/3.1/*, especially for login. If you try to use /login for the API, you'll end up at the Looker UI login page, which won't work for API requests.
This might come in handy when using tools that leveraging looker API's, such as gazer, henry, etc.
You can double check by hitting the /alive endpoint on a given port to check:
curl -i https://[instanceurl]:19999/alive
curl -i https://[instanceurl]:443/alive