Explained: CoreDNS

You deploy a new service to your Kubernetes cluster. The pods come up healthy. You open a shell inside one of them and try to reach another service by name — http://payments-service — and nothing happens. Timeout. You try the full name: http://payments-service.billing.svc.cluster.local . Still nothing. You try the service's ClusterIP directly, and it works fine. Something in the cluster is resolving names, but it's not resolving yours. If … Read More

Architecture: Kafka

Every time you place an order, stream a video, or tap a payment terminal, dozens of systems need to know about it — simultaneously, reliably, in order. Getting data from where it's produced to where it needs to be processed, at scale, without losing anything, is one of the hardest problems in distributed systems. Apache Kafka was built specifically to solve it. Kafka is now the backbone of real-time data infrastructure at most large technolog… Read More

Architecture: Zscaler

You open your laptop at home, connect to the company network, and almost immediately a login prompt appears asking you to authenticate — again. Or a website you could access at the office is suddenly blocked. Or your IT team says "it goes through Zscaler" when you ask why something is slow. Zscaler is one of those pieces of infrastructure that affects every developer every day, but almost nobody understands how it actually works. This p… Read More