Nemlig.com's Multi-Cluster DNS Setup

Are you ready for a geeky deep-dive into the world of multi-cluster DNS setups? Buckle up, because we're about to embark on a journey through the magical realm of domain name resolution!

A multi-cluster DNS setup is like the ultimate TARDIS for your servers. Just like how the TARDIS can transport the Doctor to any location in time and space, a multi-cluster DNS setup allows users to access multiple clusters of servers from anywhere in the world, using a single, convenient domain name.

It’s super important for eCommerce sites like nemlig.com as it allows for scalability, high availability, fault tolerance, smart traffic routing, and better security. By distributing traffic across multiple clusters of servers, they're enabling the DevOps team to operate and maintain the infrastructure that runs the core business while meeting SLAs.

So whether you're a seasoned DevOps or a fresh-faced dev, join Lars and Guy to learn everything you need to know about multi-cluster DNS setup!

Transcript

1. Nemlig.com’s Multi-Cluster DNS Setup
2. Agenda Meet Lars & Guy Nemlig’s DNS Challenges The Solution How they did it?
3. Meet Our Speakers Guy Menahem Solution Architect Komodor Lars Bengtsson Lead DevOps Engineer Nemlig.com &
4. Nemlig’s Challenges • Getting a DNS record took up to 4 days • Static DNS configuration which requires manual configuration • DNS record is aware/dependant of the app location
5. The Goals • From 4 days to create a DNS record to immediate self-serve for devs • Manage DNS dynamically. Hands-off fashion when apps are deployed • Abstract away the specific Kubernetes cluster any app is running on
6. Kubernetes DNS Basics
7. Why Every Cluster Has an Internal DNS? • Internal Dynamic Resolution • Service Discovery • Cache • Upstream Forwarding
8. Internal Cluster Resolution Flow I need the credit card service, where is it? Credit Card SVC Billing Service Pod
9. Internal Cluster Resolution Flow I need the credit card service, where is it? Credit Card SVC Pod Pod Pod Cluster Core-DNS etcd Billing Service Pod
10. External Cluster Resolution Flow I need the bank service, where is it? Cluster Core-DNS 8.8.8.8 / org DNS Billing Service Pod
11. Can We Resolve in the Other Direction? Cluster Core-DNS 8.8.8.8 / org DNS Where is the billing service? Cluster Core-DNS Cluster Core-DNS
12. How Did Nemlig Solve it?
13. Nemlig’s K8s Architecture
14. Nemlig’s K8s Architecture Give me the IP formysvc.prod.tld Active Directory DNS Zone Spec K8s gateway CoreDNS >> looks up mysync.env.tld on the cluster >> returns NXDMAIN downstream cluster X Prod. Management Cluster downstream cluster y AD looks up Auth DNS for prod tld >> forwards to the exposed Auth. DNS instance (Fanout) (Fanout) User Authoritative DNS instance K8s gateway CoreDNS >> looks up mysync.env.tld on the cluster >> returns the external lPv4 of the svc
15. Q&A