Book Image

Learn Kubernetes Security

By : Kaizhe Huang, Pranjal Jumde
5 (1)
Book Image

Learn Kubernetes Security

5 (1)
By: Kaizhe Huang, Pranjal Jumde

Overview of this book

Kubernetes is an open source orchestration platform for managing containerized applications. Despite widespread adoption of the technology, DevOps engineers might be unaware of the pitfalls of containerized environments. With this comprehensive book, you'll learn how to use the different security integrations available on the Kubernetes platform to safeguard your deployments in a variety of scenarios. Learn Kubernetes Security starts by taking you through the Kubernetes architecture and the networking model. You'll then learn about the Kubernetes threat model and get to grips with securing clusters. Throughout the book, you'll cover various security aspects such as authentication, authorization, image scanning, and resource monitoring. As you advance, you'll learn about securing cluster components (the kube-apiserver, CoreDNS, and kubelet) and pods (hardening image, security context, and PodSecurityPolicy). With the help of hands-on examples, you'll also learn how to use open source tools such as Anchore, Prometheus, OPA, and Falco to protect your deployments. By the end of this Kubernetes book, you'll have gained a solid understanding of container security and be able to protect your clusters from cyberattacks and mitigate cybersecurity threats.
Table of Contents (19 chapters)
Section 1: Introduction to Kubernetes
Section 2: Securing Kubernetes Deployments and Clusters
Section 3: Learning from Mistakes and Pitfalls

Securing CoreDNS

kube-dns was the default Domain Name System (DNS) server for a Kubernetes cluster. The DNS server helps internal objects such as services, pods, and containers locate each other. kube-dns is comprised of three containers, detailed as follows:

  • kube-dns: This container uses SkyDNS to perform DNS resolution services.
  • dnsmasq: A lightweight DNS resolver. It caches responses from SkyDNS.
  • sidecar: This monitors health and handles metrics reporting for DNS.

kube-dns has been superseded by CoreDNS since version 1.11 because of security vulnerabilities in dnsmasq and performance issues in SkyDNS. CoreDNS is a single container that provides all the functions of kube-dns.

To edit the configuration file for CoreDNS, you can use kubectl, like this:

$ kubectl -n kube-system edit configmap coredns

By default, the CoreDNS config file on Minikube looks like this:

# Please edit the object below. Lines beginning with a '#' 
# will be ignored...