Configuring and leveraging CoreDNS
As mentioned earlier in this chapter, nodes, pods, and services are assigned their own IP addresses in the Kubernetes cluster. Kubernetes runs a Domain Name System (DNS) server implementation that maps the name of the service to its IP address via DNS records. So, you can reach out to the services with a consistent DNS name instead of using its IP address. This comes in very handy in the context of microservices. All microservices running in the current Kubernetes cluster can reference the service name to communicate with each other.
The DNS server mainly supports the following three types of DNS records, which are also the most common ones:
- A or AAAA records for forward lookups that map a DNS name to an IP address. A record maps a DNS name to an IPv4 address, whereas an AAAA record allows mapping a DNS name to an IPv6 address.
- SRV records for port lookups so that connections are established between a service and a hostname. ...
