Set up HTTP-to-HTTPS redirect for regional internal Application Load Balancers

This topic shows you how to use URL map redirects to redirect all internal Application Load Balancer requests from HTTP to HTTPS. The example on this page uses the well-known ports 80 (for HTTP) and 443 (for HTTPS). However, you're not required to use these specific port numbers. Each forwarding rule for an Application Load Balancer can reference a single port from 1-65535.

To configure HTTP-to-HTTPS redirects, you must create two load balancers, one for HTTPS traffic and another for HTTP traffic. Each load balancer has its own forwarding rule, target proxy, and URL map, but they share the same IP address. For the HTTP load balancer, you don't need to configure a backend because the frontend redirects traffic to the HTTPS load balancer's backend.

At a high level, to redirect HTTP traffic to HTTPS, you must do the following:

1. Create a regular internal HTTPS load balancer with a reserved, shared internal IP address.
2. Test the load balancer to make sure that it's working.

3. Redirect traffic to the HTTPS load balancer.

   To do this, you must create a partial internal HTTP load balancer that only has a frontend. The frontend receives requests and then redirects them to the HTTPS load balancer by using the following resources:

   • A forwarding rule with the same reserved internal IP address as the HTTPS load balancer you created in step 1
   • A target HTTP proxy
   • A URL map that redirects traffic to the HTTPS load balancer

As shown in the following diagram, the HTTPS load balancer is a regular load balancer with the expected Internal Application Load Balancer components.

The HTTP load balancer has the same IP address as the HTTPS load balancer and a redirect instruction in the URL map.

Internal HTTP-to-HTTPS redirect configuration (click to enlarge).

Create the internal HTTPS load balancer

To set up a regional internal Application Load Balancer, use the instructions at setting up an internal Application Load Balancer.

If you already have a functioning regional internal Application Load Balancer, make sure that it has a reserved, shared IP address for the forwarding rule, and then move on to the next section, Redirect traffic to your HTTPS load balancer.

For cross-region internal Application Load Balancers, use the instructions in Set up a cross-region internal Application Load Balancer with VM instance group backends to create two load balancers, and then follow the instructions in Redirect traffic to your HTTPS load balancer.

Redirect traffic to your HTTPS load balancer

Create a partial HTTP load balancer that has the same IP address as the HTTPS load balancer created in the previous step. The partial load balancer redirects traffic from port 80 to port 443.

Console

Start your configuration

1. In the Google Cloud console, go to the Load balancing page.

   Go to Load balancing

2. Click Create load balancer.
3. For Type of load balancer, select Application Load Balancer (HTTP/HTTPS) and click Next.
4. For Public facing or internal, select Internal and click Next.
5. For Cross-region or single region deployment, select Best for regional workloads and click Next.
6. Click Configure.

Basic configuration

1. For the name of the load balancer, enter l7-ilb-http-redirect.
2. For Region, select us-west1.
3. For Network, select lb-network.

Configure the backend service

1. Click Backend configuration.
2. In the Select backend services menu, select the existing backend service l7-ilb-backend-service.
3. Click OK.

Configure the URL map

1. Click Routing rules.
2. For Mode, select Advanced host and path rule.
3. Click Add host and path rule.

4. Set Hosts to *.

5. For Path matcher (matches, actions and services), enter the following code:

   name: matcher1
   defaultUrlRedirect:
     httpsRedirect: true
     hostRedirect: IP_ADDRESS:443
     redirectResponseCode: PERMANENT_REDIRECT
   

6. Ensure that the l7-ilb-backend-service is the only backend service for any unmatched host and any unmatched path.

For information about traffic management, see Set up traffic management for internal Application Load Balancers.

Configure the frontend for HTTP

1. Click Frontend configuration.
2. Set the name of the forwarding rule to l7-ilb-forwarding-rule.
3. Set Protocol to HTTP.
4. Set the Subnetwork to backend-subnet.
5. Set the Port to 80.
6. In the IP address menu, select the shared IP address that was reserved for the HTTPS load balancer forwarding rule.
7. Click Done.

Review the configuration

1. Click Review and finalize.
2. Review your load balancer configuration settings.
3. Optional: Click Equivalent code to view the REST API request that will be used to create the load balancer.
4. Click Create.

gcloud

1. Create a new URL map by creating a YAML file with the traffic redirect configuration. Replace IP_ADDRESS with the shared IP address that was reserved for the HTTPS load balancer forwarding rule.

   defaultService: regions/us-west1/backendServices/l7-ilb-backend-service
   kind: compute#urlMap
   name: l7-ilb-redirect-url-map
   hostRules:
   - hosts:
    - '*'
    pathMatcher: matcher1
   pathMatchers:
   - name: matcher1
    defaultUrlRedirect:
          hostRedirect: IP_ADDRESS:443
          redirectResponseCode: PERMANENT_REDIRECT
          httpsRedirect: True
   

2. Import the YAML file to the new URL map:

   gcloud compute url-maps import l7-ilb-redirect-url-map \
      --source=/tmp/url_map.yaml \
      --region=us-west1
   

3. Create the HTTP load balancer's target proxy:

   gcloud compute target-http-proxies create l7-ilb-http-proxy \
      --url-map=l7-ilb-redirect-url-map \
      --region=us-west1
   

4. Create a new forwarding rule and the shared IP address:

   gcloud compute forwarding-rules create l7-ilb-forwarding-rule \
      --load-balancing-scheme=INTERNAL_MANAGED \
      --network=lb-network \
      --subnet=backend-subnet \
      --address=IP_ADDRESS \
      --ports=80 \
      --region=us-west1 \
      --target-http-proxy=l7-ilb-http-proxy \
      --target-http-proxy-region=us-west1
   

Test the traffic redirect

1. Connect to your client VM.

   gcloud compute ssh l7-ilb-client-us-west1-a \
      --zone=us-west1-a
   

2. Send an HTTP request to IP_ADDRESS on port 80, and expect a traffic redirect.

   curl -L -k IP_ADDRESS
   

3. View the sample output.

   Page served from: l7-ilb-backend-w11t
   

   Add -vvv to see more details.

   curl -L -k IP_ADDRESS -vvv
   
   
   
   Rebuilt URL to: IP_ADDRESS/
   Trying IP_ADDRESS...
   TCP_NODELAY set
   Connected to IP_ADDRESS (IP_ADDRESS) port 80 (#0)
   > GET / HTTP/1.1
   > Host: IP_ADDRESS
   > User-Agent: curl/7.52.1
   > Accept: /
   >
   < HTTP/1.1 308 Permanent Redirect
   < location: https://IP_ADDRESS:443/
   < date: Fri, 07 Aug 2020 05:07:18 GMT
   < via: 1.1 google
   < content-length: 0
   <
   Curl_http_done: called premature == 0
   Connection #0 to host IP_ADDRESS left intact
   Issue another request to this URL: 'https://IP_ADDRESS:443/'
   Trying IP_ADDRESS...
   TCP_NODELAY set
   Connected to IP_ADDRESS (IP_ADDRESS) port 443 (#1)
   ALPN, offering h2
   ALPN, offering http/1.1
   Cipher selection: ALL:!EXPORT:!EXPORT40:!EXPORT56:!aNULL:!LOW:!RC4:@STRENGTH
   successfully set certificate verify locations:
   CAfile: /etc/ssl/certs/ca-certificates.crt
   CApath: /etc/ssl/certs
   ...
   ...
   SSL connection using TLSv1.2 / ECDHE-RSA-AES128-GCM-SHA256
   ALPN, server accepted to use h2
   Server certificate:
   subject: O=Google TESTING; CN=test_cert_1
   start date: Jan  1 00:00:00 2015 GMT
   expire date: Jan  1 00:00:00 2025 GMT
   issuer: O=Google TESTING; CN=Intermediate CA
   SSL certificate verify result: unable to get local issuer certificate (20), continuing anyway.
   Using HTTP2, server supports multi-use
   Connection state changed (HTTP/2 confirmed)
   Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
   Using Stream ID: 1 (easy handle 0x561a6b0e3ea0)
   > GET / HTTP/1.1
   > Host: IP_ADDRESS
   > User-Agent: curl/7.52.1
   > Accept: /
   >
   Connection state changed (MAX_CONCURRENT_STREAMS updated)!
   < HTTP/2 200
   < date: Fri, 07 Aug 2020 05:07:18 GMT
   < server: Apache/2.4.25 (Debian)
   < last-modified: Thu, 06 Aug 2020 13:30:21 GMT
   < etag: "2c-5ac357d7a47ec"
   < accept-ranges: bytes
   < content-length: 44
   < content-type: text/html
   < via: 1.1 google
   <
   Page served from: l7-ilb-backend-https-w11t
   Curl_http_done: called premature == 0
   Connection #1 to host IP_ADDRESS left intact
   

What's next

• To learn how internal Application Load Balancers work, see Internal Application Load Balancer overview.

• To manage the proxy-only subnet resource required by internal Application Load Balancers, see Proxy-only subnet for internal Application Load Balancers.

• Clean up the load balancer setup.