Chapter 13. Cloud DNS
An overview and history of the Domain Name System (DNS)
How the Cloud DNS API works
How Cloud DNS pricing is calculated
An example of assigning DNS names to VMs at startup
Broken down
Addressed
Transmitted
Routed
Received
Defines how applications create communication channels
Manages how a message is broken down to be transmitted
IP - Defines how to address and route packets for delivery
Application layer - HTTP, FTP, SMTP, SMNP
Transport layer
Network layer
Physical layer
Non proprietary and easily modified
Compatible with all operating systems, hardware, and networks
Highly scalable
TCP/IP is a set of network protocols that enable communication between computers. Network protocols are rules or standards that govern network communications.
It was developed in the 1970s and adopted as the protocol standard for ARPANET (the predecessor to the Internet) in 1983.
TCP/IP specifies how data is exchanged over the internet by providing end-to-end communications that identify how it should be broken into packets, addressed, transmitted, routed and received at the destination.
Each gateway computer on the network checks this IP address to determine where to forward the message.
DNS is a hierarchical distributed storage system that tracks the mapping of internet names (like www.google.com) to numerical addresses.
DNS is the internet’s phone book.
The system stores a set of “resource records,” which are the mappings from names to numbers, and splits these records across a hierarchy of “zones.”
Delegate responsibility for owning and updating subsets of records.
Pointing to specific numeric addresses (such as A or AAAA records).
Address Mapping record (A Record)—also known as a DNS host record, stores a hostname and its corresponding IPv4 address.
Storing arbitrary data (such as TXT records).
A TXT record (short for text record) is a type of resource record in the Domain name system (DNS) used to provide the ability to associate arbitrary text with a host or other name, such as human readable information about a server, network, data center, or other accounting information.
A Canonical Name record (abbreviated as CNAME record) is a type of resource record in the Domain Name System (DNS) that maps one domain name (an alias) to another (the canonical name).
An A record might say that www.google.com maps to 207.237.69.117.
A CNAME record might say that storage.googleapis.com maps to storage.l.googleapis.com.
Directs traffic that requests a URL from your domain to the resources you want to serve.
Because DNS is a distributed system and expected to be only eventually consistent , anyone can set up a server to act as a cache of DNS records.
A Records are the most basic type of DNS record and are used to point a domain or subdomain to an IP address.
Assigning a value to an A record is providing DNS with an IP address to the domain should point to a TTL.(Time To Live, or TTL for short, is the sort of expiration date that is put on a DNS record.).
Also called Address Records. A record only resolves to IP addresses.
13.1. What is Cloud DNS?
Google Cloud DNS is a managed service that acts as a DNS server and can answer DNS queries like other servers, such as BIND.
Expose an API that makes it possible to manage DNS entries automatically.
An API for managing DNS entries, you can configure virtual machines to automatically register a new DNS entry at boot time giving you friendly names such as server1.mydomain.com.
13.1.1. Example DNS entries
A name server (NS) record, which is responsible for delegating ownership to other servers;
Logical” (A or AAAA) records, which point to IP addresses of a server;
Canonical name” (CNAME) record, which acts as an alias of sorts for the domain entry.
Manage these as “zone files,” which are text files stating in a special format the exact DNS records.
Cloud DNS does exactly this: exposing zones and record sets as resources that you can create and manage.
Summary
DNS is a hierarchical storage system for tracking pointers of human-readable names to computer-understandable addresses.
Cloud DNS is a hosted, highly available set of DNS servers with an API against which we can program.
Cloud DNS charges prices based on the number of zones (domain names) and the number of DNS lookup requests.
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