oxide

DNS for InstancesWhen an instance is created, it is automatically registered in Internal DNS. In this case, the primary IPv4 and IPv6 addresses are registered as A and AAAA records. Internal DNS exists on a per-VPC basis. Using the network’s DNS servers, an instance is always able to resolve any address on the VPC. If an instance is not on that VPC, it will not be able to resolve names outside of that VPC.When an Ephemeral IP address is assigned to an instance, then that instance will appear in external DNS. Names in external DNS are accessible outside of the Oxide environment by other applications. A DNS A record is created whenever an IPv4 Ephemeral IP address is assigned and a DNS AAAA record is assigned whenever an IPv6 Ephemeral IP address is assigned.Names in DNS follow the same structure, regardless of whether or not they are being used internally or externally. This structure is:..inst....<instance> refers to the DNS name of the instance<az> refers to the DNS name of the availability zone<vpc> refers to the DNS name of the VPC<project> refers to the DNS name of the project<org> refers to the DNS name of the organization<suffix> refers to the DNS suffix that is used. For internal DNS this is always .internal. For external DNS, this varies based on the installation.Let’s look at an example. Here are two names that refer to the same instance. One is in internal DNS and one is in external DNS:glorfindel.us-east-1.inst.gondolin.noldor.tolkien.internal glorfindel.us-east-1.inst.gondolin.noldor.tolkien.oxide.fingolfin.orgHere glorfindel is the DNS name of the instance. us-east-1 is the DNS name of the availability zone. gondolin is the DNS name of the VPC, noldor is the DNS name of the project, and tolkien is the DNS name of the organization. The first DNS host name is the name in internal DNS, which is why it has the .internal suffix. The second name is the one in external DNS and oxide.fingolfin.org is the suffix. The DNS suffix is specific to an installation.In all of the above objects, we explicitly said it was the DNS name. The DNS name is a separate name for each object that defaults to the object’s name. DNS has some additional constraints in terms of naming that aren’t always there for the main name attributes. In addition, it’s important that renaming something that users see and interact with on a regular basis doesn’t impact the names that machines are using unless intended.When two VPCs have been peered together, subnets that are shared will show up in DNS with the corresponding names that match that project.