20170330_kubeCon_2.1
20170330_kubeCon_2.1
2 - Presentations
2.1 - CoreDNS
Intro
Was involved in SkyDNS
Using etcd as a backend
SkyDNS was 1 simple function wich did everything
-> Wanted to rework Skydns
-> Forked and started the CoreDNS thing
What is Service discovery ?
DNS protocol has a SRV record
<SERVICE>._<PROTO>.domain.com. SRV priority weight port target.
DNS protocol
DNS started as a simple protocol
* (very) old RFCs
* Lots of RFCs that extended the protocol
* RFCs are not respected by everybody
CoreDNS Demo
Basics
* Reads ETCD records
* Translate as DNS records
Supports GRPC
Project / Issues
- Dig is your only friend
- DNS is old and not easy to use, debug, explore …
- UDP for 512 Bytes max
- Fallback to TCP
- But oftenly blocked by FWs
- MAX 64k bytes
- After -> you are screwed
SkyDNS / CoreDNS
Mutli zones support in CoreDNS