I'm trying to set up a load balancer using a serverless backend service (App engine). I followed the tutorial here
The external IP address is reserved
the SSL certificate was created (clicking on the SSL cert. name shows the domain status with green ticks, and certificate chain)
So, the frontend seems to be functional. The problem I have seems to come from the backend.
I selected a Serverless NEG as Backend type; HTTP/2 protocol; I enabled Cloud CDN and the recommended cache static content Cache mode.
I added a new backend. The selected region is 'Central US' just like with my AppEngine. As for the NEG Type, I selected App Engine, and the default service name.
I think I have the most basic backend configuration we can have here. But something is not working. This : https://LOAD_BALANCER_IP_ADDRESS loads a 404, along with Content Security Policy errors (The page’s settings blocked the loading of a resource at inline (“default-src”)).
The troubleshooting guide says a 404 is due to the serverless resource that doesn't exist. However, if I reset my custom DNS settings so they don't point to the LB, it does work. My App engine is there and it's operational. The App Engine logs are there to confirm it.
It seems to me the problem comes from the backend instance of the LB.
Now, in the load balancing menu, I go to the 'Backends' section at the top, and select my backend. Here I have the list of 'General properties' of my backend. Except, under 'Backends', it says the following : Backends contain instance groups of VMs or network endpoint groups. This backend service has no backends yet edit
From there, I can click the edit link, which redirects me to the 'Backend service edit' menu. I DO have a backend selected in there. I did create a serverless NEG using App Engine, as explained above.
We have the option to see a monitoring chart, when we select the LB, then the monitoring section. In my case, it shows traffic is balanced between Europe/America/Asia, the backend service subsection shows the name of my backend service. However, the bottom subsection named 'Backend Instance' shows : NO_BACKEND_SELECTED
I'm assuming this is where the issue is. Has anyone been able to build the same configuration with App Engine ? What does NO_BACKEND_SELECTED mean ? There is no explanation on Google's doc.
