Creating CNAME for Google Cloud Functions

Creating CNAME for Google Cloud Functions

In this blog, we will create a CNAME for our cloud functions with path matches. The problem with cloud functions is that they use long URLs. We will be using the load balancer method to create a CNAME. We will create three path matches for three separate cloud functions.

  • Firstly we have to create a domain name in any domain registrar of your choice like Cloudflare. For example mysamplefunctions.com
  • To use this method we need a project owner or project editor role or the following permissions

Network Admin: Create load balancer and networking components

Compute Instance Admin: Create and modify NEGs

Security Admin: Create and modify SSL certificates

  • We need to set up a global IP address to reach the load balancer
    Run the following command

gcloud compute addresses create function-ip
--network-tier=PREMIUM
--ip-version=IPV4
--global

gcloud compute addresses describe function-ip
--format="get(address)"
--global

Console

Reserving a static address
  • Create a serverless NEG (network endpoint group) for your first function let’s say. Image processor. The --cloud-function-name should be the name that you see for the function in the cloud console.

gcloud compute network-endpoint-groups create imageprocessorneg
--region=us-central1
--network-endpoint-type=serverless
--cloud-function-name=imageprocessor

Console

Creating a network endpoint group

Add the FQDN and keep the other fields as is

filling details of the network  endpoint group
  • Create a backend service for the same.

gcloud compute backend-services create imageprocessorservice
--load-balancing-scheme=EXTERNAL
--global

You cannot create a global backend service from the console. To create a regional backend service

new regional backend service

Specify the network endpoint group name created in the previous step in the below drop-down menu.

adding the network endpoint group
  • Add the serverless NEG as a backend-to-backend service

gcloud compute backend-services add-backend imageprocessorservice
--global
--network-endpoint-group=imageprocessorneg
--network-endpoint-group-region=us-central1

  • Create a NEG for your second Cloudrun service let’s say video processor. The --cloud-function-name should be the name that you see for the function in the cloud console

gcloud compute network-endpoint-groups create videoprocessorneg
--region=us-central1
--network-endpoint-type=serverless
--cloud-function-name=videoprocessor

  • Create backend service for same.

gcloud compute backend-services create videoprocessorservice
--load-balancing-scheme=EXTERNAL
--global

  • Add serverless NEG as backend to backend service.

gcloud compute backend-services add-backend videoprocessorservice
--global
--network-endpoint-group=videoprocessorneg
--network-endpoint-group-region=us-central1

  • Create a NEG for your third Cloudrun service let’s say audio processor. The --cloud-function-name should be the name that you see for the function in the cloud console

gcloud compute network-endpoint-groups create audioprocessorneg
--region=us-central1
--network-endpoint-type=serverless
--cloud-function-name=audioprocessor

  • Create backend service for same.

gcloud compute backend-services create audioprocessorservice
--load-balancing-scheme=EXTERNAL
--global

  • Add serverless NEG as a backend to backend service.

gcloud compute backend-services add-backend audioprocessorservice
--global
--network-endpoint-group=audioprocessorneg
--network-endpoint-group-region=us-central1

  • Create a URL map to route incoming requests to the backend service.

gcloud compute url-maps create myurlmap
--default-service imageprocessorservice

             --default-service imageprocessorservice

The --default-service will be used if no path is specified in the url.

  • Create path matchers for all the services.

gcloud compute url-maps add-path-matcher myurlmap
--path-matcher-name=service-matcher
--new-hosts=mysamplefunctions.com
--default-service=imageprocessorservice
--backend-service-path-rules='/image=imageprocessorservice,/video=videoprocessorservice,/audio=audioprocessorservice'

  • Create a target HTTP(S) proxy to route requests to your URL map.
gcloud compute target-http-proxies create myhttpproxy \
            --url-map=myurlmap

Console steps 13, 14, and 15:
a. Create a http load balancer

create a http load balancer

 b. Select the backend services created in the previous step

select backend service created

 c. Add the host and path rules. Add the respective backend services in the last column.

adding host and path rules

 d. Click Create

  • Create a global forwarding rule to route incoming requests to the proxy.
gcloud compute forwarding-rules create myhttpforwadingrule \
          --load-balancing-scheme=EXTERNAL \
          --network-tier=PREMIUM \
          --address=function-ip \
          --target-http-proxy=myhttpproxy \
          --global \
          --ports=80
  • After the load balancer is created, note the IP address that is associated with the load balancer: for example, 30.90.80.100. To point your domain to your load balancer, create an A record using your domain registration service.
  • Make sure that proxy is disabled in the domain registrar like Cloudflare so the traffic is routed to the load balancer.
  • So you can now access the functions in the following manner.
    – For image processor
    mysamplefucntions.com/image
    – For video processor.
    mysamplefucntions.com/video
    – For Audio processor.
    myaudioprocessor.com/audio
  • The document for reference are
  1. https://cloud.google.com/load-balancing/docs/https/setting-up-https-serverless#gcloud:-cloud-functions
  2. https://cloud.google.com/load-balancing/docs/url-map-concepts
  3. https://cloud.google.com/load-balancing/docs/negs/serverless-neg-concepts

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