Set up a regional internal Application Load Balancer with hybrid connectivity

This page illustrates how to deploy a regional internal Application Load Balancer to load balance traffic to network endpoints that are on-premises or in other public clouds and are reachable by using hybrid connectivity.

If you haven't already done so, review the Hybrid connectivity NEGs overview to understand the network requirements to set up hybrid load balancing.

Setup overview

The example on this page sets up the following deployment:

Regional internal Application Load Balancer example for hybrid connectivity (click to enlarge).

You must configure hybrid connectivity before setting up a hybrid load balancing deployment. This page does not include the hybrid connectivity setup.

Depending on your choice of hybrid connectivity product (either Cloud VPN or Cloud Interconnect (Dedicated or Partner)), use the relevant product documentation.

Permissions

To set up hybrid load balancing, you must have the following permissions:

• On Google Cloud

  • Permissions to establish hybrid connectivity between Google Cloud and your on-premises environment or other cloud environments. For the list of permissions needed, see the relevant Network Connectivity product documentation.
  • Permissions to create a hybrid connectivity NEG and the load balancer. The Compute Load Balancer Admin role (roles/compute.loadBalancerAdmin) contains the permissions required to perform the tasks described in this guide.

• On your on-premises environment or other non-Google Cloud cloud environment

  • Permissions to configure network endpoints that allow services on your on-premises environment or other cloud environments to be reachable from Google Cloud by using an IP:Port combination. For more information, contact your environment's network administrator.
  • Permissions to create firewall rules on your on-premises environment or other cloud environments to allow Google's health check probes to reach the endpoints.

Additionally, to complete the instructions on this page, you need to create a hybrid connectivity NEG, a load balancer, and zonal NEGs (and their endpoints) to serve as Google Cloud-based backends for the load balancer.

You should be either a project Owner or Editor, or you should have the following Compute Engine IAM roles.

Task	Required role
Create networks, subnets, and load balancer components	Compute Network Admin (roles/compute.networkAdmin)
Add and remove firewall rules	Compute Security Admin (roles/compute.securityAdmin)
Create instances	Compute Instance Admin (roles/compute.instanceAdmin)

Establish hybrid connectivity

Your Google Cloud and on-premises environment or other cloud environments must be connected through hybrid connectivity by using either Cloud Interconnect VLAN attachments or Cloud VPN tunnels with Cloud Router. We recommend that you use a high availability connection.

A Cloud Router enabled with global dynamic routing learns about the specific endpoint through Border Gateway Protocol (BGP) and programs it into your Google Cloud VPC network. Regional dynamic routing is not supported. Static routes are also not supported.

The VPC network that you use to configure either Cloud Interconnect or Cloud VPN is the same network that you use to configure the hybrid load balancing deployment. Ensure that your VPC network's subnet CIDR ranges do not conflict with your remote CIDR ranges. When IP addresses overlap, subnet routes are prioritized over remote connectivity.

For instructions, see the following documentation:

• Cloud VPN
• Cloud Interconnect

Important: Do not proceed with the instructions on this page until you set up hybrid connectivity between your environments.

Set up your environment that is outside Google Cloud

Perform the following steps to set up your on-premises environment or other cloud environment for hybrid load balancing:

• Configure network endpoints to expose on-premises services to Google Cloud (IP:Port).
• Configure firewall rules on your on-premises environment or other cloud environment.
• Configure Cloud Router to advertise certain required routes to your private environment.

Set up network endpoints

After you set up hybrid connectivity, you configure one or more network endpoints within your on-premises environment or other cloud environments that are reachable through Cloud Interconnect or Cloud VPN by using an IP:port combination. This IP:port combination is configured as one or more endpoints for the hybrid connectivity NEG that is created in Google Cloud later on in this process.

If there are multiple paths to the IP endpoint, routing follows the behavior described in the Cloud Router overview.

Set up firewall rules

The following firewall rules must be created on your on-premises environment or other cloud environment:

• Create an ingress allow firewall rule in on-premises or other cloud environments to allow traffic from the region's proxy-only subnet to reach the endpoints.

• If you're using a combination of hybrid and zonal NEGs in a single backend service, you need to allowlist the Google health check probe ranges for the zonal NEGs.

Advertise routes

Configure Cloud Router to advertise the following custom IP ranges to your on-premises environment or other cloud environment:

• The range of the region's proxy-only subnet.

Set up Google Cloud environment

For the following steps, make sure you use the same VPC network (called NETWORK in this procedure) that was used to configure hybrid connectivity between the environments.

Additionally, make sure the region used (called REGION in this procedure) is the same as that used to create the Cloud VPN tunnel or Cloud Interconnect VLAN attachment.

Configure the proxy-only subnet

This proxy-only subnet is used for all regional Envoy-based load balancers in the REGION region.

Console

1. In the Google Cloud console, go to the VPC networks page.
   Go to VPC networks
2. Go to the network that was used to configure hybrid connectivity between the environments.
3. Click Add subnet.
4. Enter a Name: PROXY_ONLY_SUBNET_NAME.
5. Select a Region: REGION.
6. Set Purpose to Regional Managed Proxy.
7. Enter an IP address range: PROXY_ONLY_SUBNET_RANGE.
8. Click Add.

gcloud

Create the proxy-only subnet with the gcloud compute networks subnets create command.

gcloud compute networks subnets create PROXY_ONLY_SUBNET_NAME \
  --purpose=REGIONAL_MANAGED_PROXY \
  --role=ACTIVE \
  --region=REGION \
  --network=NETWORK \
  --range=PROXY_ONLY_SUBNET_RANGE

Configure the load balancer subnet

This subnet is used to create the load balancer's zonal NEG backends, the frontend, and the internal IP address.

Cloud console

1. In the Google Cloud console, go to the VPC networks page.
   Go to VPC networks
2. Go to the network that was used to configure hybrid connectivity between the environments.
3. In the Subnets section:
   • Set the Subnet creation mode to Custom.
   • In the New subnet section, enter the following information:
     • Name: LB_SUBNET_NAME
     • Region: REGION
     • IP address range: LB_SUBNET_RANGE
   • Click Done.
4. Click Create.

gcloud

1. Create a subnet in the network that was used to configure hybrid connectivity between the environments.

   gcloud compute networks subnets create LB_SUBNET_NAME \
       --network=NETWORK \
       --range=LB_SUBNET_RANGE \
       --region=REGION
   

Reserve the load balancer's IP address

By default, one IP address is used for each forwarding rule. You can reserve a shared IP address, which lets you use the same IP address with multiple forwarding rules. However, if you want to publish the load balancer by using Private Service Connect, do not use a shared IP address for the forwarding rule.

Console

You can reserve a standalone internal IP address using the Google Cloud console.

1. Go to the VPC networks page.

   Go to VPC networks

2. Click the network that was used to configure hybrid connectivity between the environments.
3. Click Static internal IP addresses and then click Reserve static address.
4. Enter a Name: LB_IP_ADDRESS.
5. For the Subnet, select LB_SUBNET_NAME.
6. If you want to specify which IP address to reserve, under Static IP address, select Let me choose, and then fill in a Custom IP address. Otherwise, the system automatically assigns an IP address in the subnet for you.
7. If you want to use this IP address with multiple forwarding rules, under Purpose, choose Shared.
8. Click Reserve to finish the process.

gcloud

1. Using the gcloud CLI, run the compute addresses create command:

   gcloud compute addresses create LB_IP_ADDRESS \
     --region=REGION \
     --subnet=LB_SUBNET_NAME \
   

2. Use the compute addresses describe command to view the allocated IP address:

   gcloud compute addresses describe LB_IP_ADDRESS \
     --region=REGION
   

   If you want to use the same IP address with multiple forwarding rules, specify --purpose=SHARED_LOADBALANCER_VIP.

Create firewall rules for zonal NEGs

In this example, you create the following firewall rules for the zonal NEG backends on Google Cloud:

• fw-allow-health-check: An ingress rule, applicable to the instances being load balanced, that allows traffic from Google Cloud health checking systems (130.211.0.0/22 and 35.191.0.0/16). This example uses the target tag allow-health-check to identify the backend VMs to which it should apply. If you're using a combination of hybrid and zonal NEGs in a single backend service, you need to allowlist the Google health check probe ranges for the zonal NEGs.
• fw-allow-ssh: An ingress rule that allows incoming SSH connectivity on TCP port 22 from any address. You can choose a more restrictive source IP range for this rule; for example, you can specify just the IP ranges of the systems from which you will initiate SSH sessions. This example uses the target tag allow-ssh to identify the VMs to which it should apply.

• fw-allow-proxy-only-subnet: An ingress rule that allows connections from the proxy-only subnet to reach the backends.

Console

1. In the Google Cloud console, go to the Firewall policies page.
   Go to Firewall policies
2. Click Create firewall rule to create the rule to allow traffic from health check probes:
   1. Enter a Name of fw-allow-health-check.
   2. Under Network, select NETWORK.
   3. Under Targets, select Specified target tags.
   4. Populate the Target tags field with allow-health-check.
   5. Set Source filter to IPv4 ranges.
   6. Set Source IPv4 ranges to 130.211.0.0/22 and 35.191.0.0/16.
   7. Under Protocols and ports, select Specified protocols and ports.
   8. Select TCP and then enter 80 for the port number.
   9. Click Create.
3. Click Create firewall rule again to create the rule to allow incoming SSH connections:
   1. Name: fw-allow-ssh
   2. Network: NETWORK
   3. Priority: 1000
   4. Direction of traffic: ingress
   5. Action on match: allow
   6. Targets: Specified target tags
   7. Target tags: allow-ssh
   8. Source filter: IPv4 ranges
   9. Source IPv4 ranges: 0.0.0.0/0
   10. Protocols and ports: Choose Specified protocols and ports.
   11. Select TCP and then enter 22 for the port number.
   12. Click Create.
4. Click Create firewall rule again to create the rule to allow incoming connections from the proxy-only subnet:
   1. Name: fw-allow-proxy-only-subnet
   2. Network: NETWORK
   3. Priority: 1000
   4. Direction of traffic: ingress
   5. Action on match: allow
   6. Targets: Specified target tags
   7. Target tags: allow-proxy-only-subnet
   8. Source filter: IPv4 ranges
   9. Source IPv4 ranges: PROXY_ONLY_SUBNET_RANGE
   10. Protocols and ports: Choose Specified protocols and ports
   11. Select TCP and then enter 80 for the port number.
   12. Click Create.

gcloud

1. Create the fw-allow-health-check-and-proxy rule to allow the Google Cloud health checks to reach the backend instances on TCP port 80:

   gcloud compute firewall-rules create fw-allow-health-check \
       --network=NETWORK \
       --action=allow \
       --direction=ingress \
       --target-tags=allow-health-check \
       --source-ranges=130.211.0.0/22,35.191.0.0/16 \
       --rules=tcp:80
   

2. Create the fw-allow-ssh firewall rule to allow SSH connectivity to VMs with the network tag allow-ssh. When you omit source-ranges, Google Cloud interprets the rule to mean any source.

   gcloud compute firewall-rules create fw-allow-ssh \
       --network=NETWORK \
       --action=allow \
       --direction=ingress \
       --target-tags=allow-ssh \
       --rules=tcp:22
   

3. Create an ingress allow firewall rule for the proxy-only subnet to allow the load balancer to communicate with backend instances on TCP port 80:

   gcloud compute firewall-rules create fw-allow-proxy-only-subnet \
       --network=NETWORK \
       --action=allow \
       --direction=ingress \
       --target-tags=allow-proxy-only-subnet \
       --source-ranges=PROXY_ONLY_SUBNET_RANGE \
       --rules=tcp:80
   

Set up the zonal NEG

For Google Cloud-based backends, we recommend you configure multiple zonal NEGs in the same region where you configured hybrid connectivity.

For this example, we set up a zonal NEG (with GCE_VM_IP_PORT type endpoints) in the REGION region. First create the VMs in the GCP_NEG_ZONE zone. Then create a zonal NEG in the same GCP_NEG_ZONE and add the VMs' network endpoints to the NEG.

Create VMs

Console

1. Go to the VM instances page in the Google Cloud console.
   Go to VM instances
2. Click Create instance.
3. Set the Name to vm-a1.
4. For the Region, choose REGION, and choose any Zone. This will be referred to as GCP_NEG_ZONE in this procedure.
5. In the Boot disk section, ensure that the Debian operating system and the 10 (buster) version are selected for the boot disk options. Click Choose to change the image if necessary.

6. Click Advanced options and make the following changes:

   • Click Networking and add the following Network tags: allow-ssh,allow-health-check, and allow-proxy-only-subnet.
   • Click Edit under Network interfaces and make the following changes then click Done:
     • Network: NETWORK
     • Subnet: LB_SUBNET_NAME
     • Primary internal IP: Ephemeral (automatic)
     • External IP: Ephemeral

   • Click Management. In the Startup script field, copy and paste the following script contents. The script contents are identical for all four VMs:

     #! /bin/bash
     apt-get update
     apt-get install apache2 -y
     a2ensite default-ssl
     a2enmod ssl
     vm_hostname="$(curl -H "Metadata-Flavor:Google" \
     http://metadata.google.internal/computeMetadata/v1/instance/name)"
     echo "Page served from: $vm_hostname" | \
     tee /var/www/html/index.html
     systemctl restart apache2
     

7. Click Create.

8. Repeat the following steps to create a second VM, using the following name and zone combination:

   • Name: vm-a2, zone: GCP_NEG_ZONE

gcloud

Create the VMs by running the following command two times, using these combinations for the name of the VM and its zone. The script contents are identical for both VMs.

• VM_NAME of vm-a1 and any GCP_NEG_ZONE zone of your choice

• VM_NAME of vm-a2 and the same GCP_NEG_ZONE zone

  gcloud compute instances create VM_NAME \
      --zone=GCP_NEG_ZONE \
      --image-family=debian-10 \
      --image-project=debian-cloud \
      --tags=allow-ssh,allow-health-check,allow-proxy-only-subnet \
      --subnet=LB_SUBNET_NAME \
      --metadata=startup-script='#! /bin/bash
        apt-get update
        apt-get install apache2 -y
        a2ensite default-ssl
        a2enmod ssl
        vm_hostname="$(curl -H "Metadata-Flavor:Google" \
        http://metadata.google.internal/computeMetadata/v1/instance/name)"
        echo "Page served from: $vm_hostname" | \
        tee /var/www/html/index.html
        systemctl restart apache2'
  

Create the zonal NEG

Console

To create a zonal network endpoint group:

1. Go to the Network Endpoint Groups page in the Google Cloud console.
   Go to the Network Endpoint Groups page
   
2. Click Create network endpoint group.
3. Enter a Name for the zonal NEG. Referred to as GCP_NEG_NAME in this procedure.
4. Select the Network endpoint group type: Network endpoint group (Zonal).
5. Select the Network: NETWORK
6. Select the Subnet: LB_SUBNET_NAME
7. Select the Zone: GCP_NEG_ZONE
8. Enter the Default port: 80.
9. Click Create.

Add endpoints to the zonal NEG:

1. Go to the Network Endpoint Groups page in the Google Cloud console.
   Go to the Network endpoint groups
   
2. Click the Name of the network endpoint group created in the previous step (GCP_NEG_NAME). You see the Network endpoint group details page.
3. In the Network endpoints in this group section, click Add network endpoint. You see the Add network endpoint page.
4. Select a VM instance to add its internal IP addresses as network endpoints. In the Network interface section, the name, zone, and subnet of the VM is displayed.
5. Enter the IP address of the new network endpoint.
6. Select the Port type.
   1. If you select Default, the endpoint uses the default port 80 for all endpoints in the network endpoint group. This is sufficient for our example because the Apache server is serving requests at port 80.
   2. If you select Custom, enter the Port number for the endpoint to use.
7. To add more endpoints, click Add network endpoint and repeat the previous steps.
8. After you add all the endpoints, click Create.

gcloud

1. Create a zonal NEG (with GCE_VM_IP_PORT endpoints) using the gcloud compute network-endpoint-groups create command:

   gcloud compute network-endpoint-groups create GCP_NEG_NAME \
       --network-endpoint-type=GCE_VM_IP_PORT \
       --zone=GCP_NEG_ZONE \
       --network=NETWORK \
       --subnet=LB_SUBNET_NAME
   

   You can either specify a --default-port while creating the NEG, or specify a port number for each endpoint as shown in the next step.

2. Add endpoints to GCP_NEG_NAME.

   gcloud compute network-endpoint-groups update GCP_NEG_NAME \
       --zone=GCP_NEG_ZONE \
       --add-endpoint='instance=vm-a1,port=80' \
       --add-endpoint='instance=vm-a2,port=80'
   

Set up the hybrid connectivity NEG

When creating the NEG, use a ZONE that minimizes the geographic distance between Google Cloud and your on-premises or other cloud environment. For example, if you are hosting a service in an on-premises environment in Frankfurt, Germany, you can specify the europe-west3-a Google Cloud zone when you create the NEG.

Moreover, if you're using Cloud Interconnect, the ZONE used to create the NEG should be in the same region where the Cloud Interconnect attachment was configured.

For the available regions and zones, see the Compute Engine documentation: Available regions and zones.

Console

To create a hybrid connectivity network endpoint group:

1. Go to the Network Endpoint Groups page in the Google Cloud console.
   Go to Network endpoint groups
   
2. Click Create network endpoint group.
3. Enter a Name for the hybrid NEG. Referred to as ON_PREM_NEG_NAME in this procedure.
4. Select the Network endpoint group type: Hybrid connectivity network endpoint group (Zonal).
5. Select the Network: NETWORK
6. Select the Subnet: LB_SUBNET_NAME
7. Select the Zone: ON_PREM_NEG_ZONE
8. Enter the Default port.
9. Click Create

Add endpoints to the hybrid connectivity NEG:

1. Go to the Network Endpoint Groups page in the Google Cloud console.
   Go to the Network Endpoint Groups page
   
2. Click the Name of the network endpoint group created in the previous step (ON_PREM_NEG_NAME). You see the Network endpoint group detail page.
3. In the Network endpoints in this group section, click Add network endpoint. You see the Add network endpoint page.
4. Enter the IP address of the new network endpoint.
5. Select the Port type.
   1. If you select Default, the endpoint uses the default port for all endpoints in the network endpoint group.
   2. If you select Custom, you can enter a different Port number for the endpoint to use.
6. To add more endpoints, click Add network endpoint and repeat the previous steps.
7. After you add all the non-Google Cloud endpoints, click Create.

gcloud

1. Create a hybrid connectivity NEG using the gcloud compute network-endpoint-groups create command.

   gcloud compute network-endpoint-groups create ON_PREM_NEG_NAME \
       --network-endpoint-type=NON_GCP_PRIVATE_IP_PORT \
       --zone=ON_PREM_NEG_ZONE \
       --network=NETWORK
   

2. Add the on-premises backend VM endpoint to ON_PREM_NEG_NAME:

   gcloud compute network-endpoint-groups update ON_PREM_NEG_NAME \
       --zone=ON_PREM_NEG_ZONE \
       --add-endpoint="ip=ON_PREM_IP_ADDRESS_1,port=PORT_1" \
       --add-endpoint="ip=ON_PREM_IP_ADDRESS_2,port=PORT_2"
   

You can use this command to add the network endpoints you previously configured on-premises or in your cloud environment. Repeat --add-endpoint as many times as needed.

You can repeat these steps to create multiple hybrid NEGs if needed.

Configure the load balancer

Console

Note: You cannot use the Google Cloud console to create a load balancer that has mixed zonal and hybrid connectivity NEG backends in a single backend service. Use either gcloud or the REST API instead.

gcloud

1. Create a health check for the backends.

      gcloud compute health-checks create http HTTP_HEALTH_CHECK_NAME \
          --region=REGION \
          --use-serving-port
      

   Health check probes for hybrid NEG backends originate from Envoy proxies in the proxy-only subnet, whereas probes for zonal NEG backends originate from [Google's central probe IP ranges](/load-balancing/docs/health-check-concepts#ip-ranges).
2. Create a backend service for Google Cloud-based backends. You add both the zonal NEG and the hybrid connectivity NEG as backends to this backend service.

     gcloud compute backend-services create BACKEND_SERVICE \
         --load-balancing-scheme=INTERNAL_MANAGED \
         --protocol=HTTP \
         --health-checks=HTTP_HEALTH_CHECK_NAME \
         --health-checks-region=REGION \
         --region=REGION
     

3. Add the zonal NEG as a backend to the backend service.

   gcloud compute backend-services add-backend BACKEND_SERVICE \
       --region=REGION \
       --balancing-mode=RATE \
       --max-rate-per-endpoint=MAX_REQUEST_RATE_PER_ENDPOINT \
       --network-endpoint-group=GCP_NEG_NAME \
       --network-endpoint-group-zone=GCP_NEG_ZONE
   

   For details about configuring the balancing mode, see the gcloud CLI documentation for the --max-rate-per-endpoint parameter.
4. Add the hybrid NEG as a backend to the backend service.

   gcloud compute backend-services add-backend BACKEND_SERVICE \
       --region=REGION \
       --balancing-mode=RATE \
       --max-rate-per-endpoint=MAX_REQUEST_RATE_PER_ENDPOINT \
       --network-endpoint-group=ON_PREM_NEG_NAME \
       --network-endpoint-group-zone=ON_PREM_NEG_ZONE
   

   For details about configuring the balancing mode, see the gcloud CLI documentation for the --max-rate-per-endpoint parameter.
5. Create a URL map to route incoming requests to the backend service:

   gcloud compute url-maps create URL_MAP_NAME \
       --default-service BACKEND_SERVICE \
       --region=REGION
   

6. Perform this step only if you want to create an HTTPS load balancer. This is not required for HTTP load balancers.
   To create an HTTPS load balancer, you must have an SSL certificate resource to use in the HTTPS target proxy. You can create an SSL certificate resource using either a Google-managed SSL certificate or a self-managed SSL certificate. Using Google-managed certificates is recommended because Google Cloud obtains, manages, and renews these certificates automatically.
   
   To create a Google-managed certificate, you must have a domain. If you do not have a domain, you can use a self-signed SSL certificate for testing.
   
   To create a Google-managed SSL certificate resource:

   gcloud compute ssl-certificates create SSL_CERTIFICATE_NAME \
       --domains DOMAIN
   

   To create a self-managed SSL certificate resource:

   gcloud compute ssl-certificates create SSL_CERTIFICATE_NAME \
       --certificate CRT_FILE_PATH \
       --private-key KEY_FILE_PATH
   

7. Create a target HTTP(S) proxy to route requests to your URL map.
   
   For an HTTP load balancer, create an HTTP target proxy:

   gcloud compute target-http-proxies create TARGET_HTTP_PROXY_NAME \
       --url-map=URL_MAP_NAME \
       --url-map-region=REGION \
       --region=REGION
   

   For an HTTPS load balancer, create an HTTPS target proxy. The proxy is the portion of the load balancer that holds the SSL certificate for HTTPS Load Balancing, so you also load your certificate in this step.

   gcloud compute target-https-proxies create TARGET_HTTPS_PROXY_NAME \
       --ssl-certificates=SSL_CERTIFICATE_NAME \
       --url-map=URL_MAP_NAME \
       --url-map-region=REGION \
       --region=REGION
   

8. Create a forwarding rule to route incoming requests to the proxy. Don't use the proxy-only subnet to create the forwarding rule.
   
   For an HTTP load balancer:

     gcloud compute forwarding-rules create HTTP_FORWARDING_RULE_NAME \
         --load-balancing-scheme=INTERNAL_MANAGED \
         --network=NETWORK \
         --subnet=LB_SUBNET_NAME \
         --address=LB_IP_ADDRESS \
         --ports=80 \
         --region=REGION \
         --target-http-proxy=TARGET_HTTP_PROXY_NAME \
         --target-http-proxy-region=REGION
   

   For an HTTPS load balancer:

     gcloud compute forwarding-rules create HTTPS_FORWARDING_RULE_NAME \
         --load-balancing-scheme=INTERNAL_MANAGED \
         --network=NETWORK \
         --subnet=LB_SUBNET_NAME \
         --address=LB_IP_ADDRESS \
         --ports=443 \
         --region=REGION \
         --target-https-proxy=TARGET_HTTPS_PROXY_NAME \
         --target-https-proxy-region=REGION
   

Connect your domain to your load balancer

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 by using your domain registration service. If you added multiple domains to your SSL certificate, you must add an A record for each one, all pointing to the load balancer's IP address. For example, to create A records for www.example.com and example.com, use the following:

NAME                  TYPE     DATA
www                   A        30.90.80.100
@                     A        30.90.80.100

If you are using Google Domains, for more information, see Google Domains Help.

Testing the load balancer

To test the load balancer, create a client VM in the same region as the load balancer. Then send traffic from the client to the load balancer.

Create a client VM

This example creates a client VM (vm-client) in the same region as the backend NEGs. The client is used to validate the load balancer's configuration and demonstrate expected behavior as described in the testing section.

Console

1. Go to the VM instances page in the Google Cloud console.
   Go to VM instances
2. Click Create instance.
3. Set the Name to vm-client.
4. Set the Zone to CLIENT_VM_ZONE.
5. Click Advanced options and make the following changes:
   • Click Networking and add the allow-ssh to Network tags.
   • Click the edit button under Network interfaces and make the following changes then click Done:
     • Network: NETWORK
     • Subnet: LB_SUBNET_NAME
     • Primary internal IP: Ephemeral (automatic)
     • External IP: Ephemeral
6. Click Create.

gcloud

The client VM can be in any zone in the same region as the load balancer, and it can use any subnet in that region. In this example, the client is in the CLIENT_VM_ZONE zone, and it uses the same subnet as the backend VMs.

gcloud compute instances create vm-client \
    --zone=CLIENT_VM_ZONE \
    --image-family=debian-10 \
    --image-project=debian-cloud \
    --tags=allow-ssh \
    --subnet=LB_SUBNET_NAME

Send traffic to the load balancer

Note: It might take a few minutes for the load balancer configuration to propagate globally after you first deploy it.

Now that you have configured your load balancer, you can start sending traffic to the load balancer's IP address.

• Connect via SSH to the client instance.

  gcloud compute ssh client-vm \
    --zone=CLIENT_VM_ZONE
  

• Verify that the load balancer is serving backend hostnames as expected.

  For HTTP testing, run:

  curl LB_IP_ADDRESS
  

  For HTTPS testing, run:

  curl -k -s 'https://test.example.com:443' --connect-to test.example.com:443:LB_IP_ADDRESS:443
  

The -k flag causes curl to skip certificate validation.

Testing the non-Google Cloud endpoints depends on the service you have exposed through the hybrid NEG endpoint.

What's next

• Clean up the load balancer setup.