What is the first step in configuring an external load balancer in Google Cloud?

The first step in configuring an external load balancer in Google Cloud is to define backend services. Backend services are crucial because they determine how the traffic is distributed across the various VM instances that are serving the application. When you set up backend services, you can specify important parameters such as health checks, session affinity, and the scaling policies for your instances.

Defining backend services provides a foundational setup that the load balancer relies on to intelligently route incoming traffic. Essentially, it allows you to define the resources that will be utilized by the load balancer to respond to requests.

While the other options are part of the overall configuration process, they come after the backend services are established. For example, frontend configurations are necessary to define how the load balancer interacts with clients, security policies help ensure safe transmission of data, and VM instances need to be configured to ensure there are resources available for the load balancer to manage. However, establishing backend services is the critical first step in setting up the load balancer functionality itself.