In this final instructive lesson, we're going to go in-depth on GCP's Cloud DNS service. DNS servicing is a critical make-or-break component of any web-facing application, so we want to make sure you understand GCP's approach.

So if you've worked with DNS providers before like Route 53 or maybe GoDaddy or something like that, then you understand the basic purpose. DNS providers let you publish domain names and route traffic to specific servers and infrastructure. So if we have a website running on a random IP address and we want to connect it to our domain coolsite.com, a DNS provider can create the necessary records to do that. Now, this is, of course, distinct from a domain name registrar service. Cloud DNS is not meant for purchasing domain names, but you can do that through Google as we mentioned, domains.google.com lets you buy domains. You can also buy domains from any other service including Route 53 or GoDaddy and then configure them using Google Cloud DNS. The DNS provider is actually about doing something with a domain name not buying it.

So Google Cloud DNS. How do we actually start doing things with it? Well, once we have a domain name registered and we're ready to work with it, we start by creating what are called managed zones within Cloud DNS. These are analogous to DNS zones and within GCP, there are two types: public zones and private zones. Both are just containers for DNS records. For example, you know, an A-record pointing to an IP address the difference is that public zones are visible to the public internet, while private zones can only be seen by specifically authorized VPCs—virtual private clouds—within a GCP account. So in essence, private zones are not visible to the public Internet.

Now, you will configure public zones for applications that need to be reachable by users from your public, from the public internet. For example, your main website will have a DNS name and you may create a record in a managed zone config that routes traffic to it. Now, this could be an A-record and directly at a VM listening for HTTP requests, or perhaps more likely, a load balancer that's directing traffic to your site instances. On the backend, you can make use of private zones for traffic within the VPC. So, for example, you can have an internal load balancer, with an internal DNS name that's usable by your back-end services. So now, instead of having to configure IP addresses or have some service discovery layer, you can just use a predictable DNS name internally that's configured within the private zone and have your back-end instances talk to each other that way.

Now, that use case may seem a bit complex and I will say that the ins and outs of DNS routing and traffic configuration, you know, there are other courses that go into that, we're not going to dig into that here, but I definitely recommend reading up on the official GCP DNS cloud DNS documentation if you need a deeper dive on these sort of internal use cases.

The most important takeaway here is that both public and private managed zones are a part of GCP Cloud DNS. This is your basic paradigm and your one-stop-shop for creating DNS configuration and records. We'll talk a little bit more about Cloud DNS in the demo coming up. You'll get to see kind of how it works in the console and how things are actually configured. When you're ready, we'll see you there.