Understanding Virtual Machines and Cloud Networking in Google Cloud — Part 1

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When people first start learning Google Cloud, one of the first services they usually encounter is Google Compute Engine. Compute Engine allows you to create and run virtual machines, often called VMs, in Google Cloud.

But before we can fully understand how virtual machines work in the cloud, we need to understand the network they live in.

In Google Cloud, that network is usually built inside something called a Virtual Private Cloud, or VPC.

What Is a Virtual Private Cloud?

A Virtual Private Cloud, commonly known as a VPC, is a private and secure cloud networking environment hosted inside a public cloud platform such as Google Cloud.

This may sound confusing at first. How can something be both private and inside a public cloud?

The idea is simple: Google Cloud provides the large global infrastructure, but you create your own isolated network inside it. Within that network, you can run virtual machines, store data, host websites, deploy applications, and connect different cloud resources together.

In other words, a VPC gives you the benefits of a private network while still using the scalability and flexibility of a public cloud provider.

This is one of the main reasons cloud computing is so powerful. You do not need to build your own physical data center, buy servers, manage hardware, or design a traditional private network from scratch. Instead, you can create a private cloud environment virtually, using Google Cloud’s infrastructure.

Why VPC Networking Matters

Virtual machines do not exist in isolation. They need a network so they can communicate with other resources, users, applications, databases, and the internet.

In Google Cloud, VPC networks allow you to connect cloud resources to each other and control how traffic flows between them.

With a VPC network, you can:

• Connect Compute Engine virtual machines
• Control access using firewall rules
• Segment your network using subnets
• Route traffic to specific destinations
• Connect resources to the internet
• Build secure and scalable cloud architectures

For example, you may want some virtual machines to be accessible from the internet, such as a web server. At the same time, you may want other virtual machines, such as database servers, to remain private. VPC networking helps you design this kind of structure.

Google Cloud VPC Networks Are Global

One important feature that surprises many new Google Cloud users is that Google Cloud VPC networks are global.

This means a single VPC network can span multiple regions around the world.

However, while the VPC network itself is global, subnets are regional. A subnet is a smaller segment of the larger VPC network. Each subnet belongs to a specific Google Cloud region.

For example, you could have one VPC network with subnets in:

• us-east1
• asia-east1
• europe-west1

Even though these subnets are in different regions, they can still belong to the same global VPC network.

This design makes it easier to build cloud infrastructure that is both global and organized.

Understanding Subnets

A subnet is a segmented part of a VPC network. It has its own range of IP addresses and is associated with a specific region.

Subnets are important because they help organize resources inside a cloud network. They allow you to group resources based on region, application type, environment, or security requirements.

For example, you might create separate subnets for:

• Development environments
• Production environments
• Web servers
• Application servers
• Database servers

In Google Cloud, subnets can also span multiple zones within the same region.

This means virtual machines in different zones of the same region can still belong to the same subnet.

Why This Architecture Is Useful

The global VPC and regional subnet model gives cloud architects a lot of flexibility.

Imagine you have a VPC network named vpc1. Inside that VPC, you create two subnets:

• One subnet in the asia-east1 region
• One subnet in the us-east1 region

Now imagine you create three Compute Engine virtual machines and attach them to this VPC network.

Even if those virtual machines are placed in different zones, they can still communicate through the network according to the rules you define.

This makes it easier to build applications that are resilient. If one zone has a problem, your application can continue running in another zone. At the same time, your network layout remains simple and manageable.

Expanding Subnets

Another useful feature of Google Cloud VPC networking is that you can expand the IP address range of a subnet.

This means that if your application grows and you need more IP addresses, you can increase the size of the subnet.

Even better, expanding a subnet does not affect virtual machines that are already running.

This is important because cloud environments often grow over time. A network that starts small may need to support more virtual machines, services, or applications later. Google Cloud gives you the flexibility to scale your network without disrupting existing workloads.

Bringing It All Together

Virtual machines are one of the core building blocks of cloud computing. But to use them effectively, we need to understand the network around them.

In Google Cloud, the Virtual Private Cloud provides the foundation for connecting and securing cloud resources.

A VPC allows you to create a private, isolated network inside Google Cloud’s public infrastructure. It connects resources, controls traffic, supports firewall rules, and helps organize your cloud architecture using subnets and routes.

The most important idea to remember is this:

Google Cloud VPC networks are global, while subnets are regional.

This model allows you to design cloud networks that are scalable, secure, and resilient across different regions and zones.