# Kubernetes Networking
- [Introduction](#introduction)
- [Gateway API](#gateway-api)
- [Multicloud communication for Kubernetes](#multicloud-communication-for-kubernetes)
- [Kubernetes Network Policy](#kubernetes-network-policy)
- [Cilium](#cilium)
- [Kubernetes Ingress Specification](#kubernetes-ingress-specification)
- [Xposer Kubernetes Controller To Manage Ingresses](#xposer-kubernetes-controller-to-manage-ingresses)
- [Software-Defined IP Address Management (IPAM)](#software-defined-ip-address-management-ipam)
- [CNI Container Networking Interface](#cni-container-networking-interface)
- [List of existing CNI Plugins (IPAM)](#list-of-existing-cni-plugins-ipam)
- [Project Calico](#project-calico)
- [DNS Service with CoreDNS](#dns-service-with-coredns)
- [Kubernetes Node Local DNS Cache](#kubernetes-node-local-dns-cache)
- [Kubernetes Sidecars](#kubernetes-sidecars)
## Introduction
* [kubernetes.io: The Kubernetes network model. How to implement the Kubernetes networking model](https://kubernetes.io/docs/concepts/cluster-administration/networking/)
* [ovh.com - getting external traffic into kubernetes: clusterip, nodeport, loadbalancer and ingress](https://www.ovh.com/blog/getting-external-traffic-into-kubernetes-clusterip-nodeport-loadbalancer-and-ingress/)
* [learnk8s.io: Load balancing and scaling long-lived connections in Kubernetes π](https://learnk8s.io/kubernetes-long-lived-connections)
* [stackrox.com: Kubernetes Networking Demystified: A Brief Guide](https://www.stackrox.com/post/2020/01/kubernetes-networking-demystified/)
* [medium.com: Fighting Service Latency in Microservices With Kubernetes](https://medium.com/@sindhujacynixit/fighting-service-latency-in-microservices-with-kubernetes-f5a584f5af36)
* [medium.com: Kubernetes NodePort vs LoadBalancer vs Ingress? When should I use what? π](https://medium.com/google-cloud/kubernetes-nodeport-vs-loadbalancer-vs-ingress-when-should-i-use-what-922f010849e0)
* [blog.alexellis.io: Get a LoadBalancer for your private Kubernetes cluster](https://blog.alexellis.io/ingress-for-your-local-kubernetes-cluster/)
* [dustinspecker.com: How Do Kubernetes and Docker Create IP Addresses?!](https://dustinspecker.com/posts/how-do-kubernetes-and-docker-create-ip-addresses/)
* [youtube: Kubernetes Ingress Explained Completely For Beginners](https://www.youtube.com/watch?v=VicH6KojwCI)
* [AWS and Kubernetes Networking Options and Trade-Offs (part 1)](https://www.weave.works/blog/introduction-to-kubernetes-pod-networking--part-1)
* [AWS and Kubernetes Networking Options and Trade-Offs (part 2)](https://www.weave.works/blog/aws-networking-overview---part-2)
* [AWS and Kubernetes Networking Options and Trade-Offs (part 3)](https://dzone.com/articles/aws-and-kubernetes-networking-options-and-trade-of)
* [medium: Service Types in Kubernetes? π](https://medium.com/faun/service-types-in-kubernetes-24a1587677d6) A Service enables network access to a set of Pods in Kubernetes.
* [containo.us: Kubernetes Ingress & Service API Demystified](https://containo.us/blog/kubernetes-ingress-service-api-demystified/)
* [speakerdeck.com: Kubernetes and networks. Why is this so dan hard? π](https://speakerdeck.com/thockin/kubernetes-and-networks-why-is-this-so-dang-hard)
* [eevans.co: Deconstructing Kubernetes Networking](https://eevans.co/blog/deconstructing-kubernetes-networking/)
* [externalTrafficPolicy=local on kubernetes. How to preserve the source IP in kubernetes](https://blog.getambassador.io/externaltrafficpolicy-local-on-kubernetes-e66e498212f9) externalTrafficPolicy=local is an annotation on the Kubernetes service resource that can be set to preserve the client source IP. When it is set, the actual IP address of a client is propagated to the K8s service instead of the IP address of the node.
* [ronaknathani.com: How a Kubernetes Pod Gets an IP Address π](https://ronaknathani.com/blog/2020/08/how-a-kubernetes-pod-gets-an-ip-address/)
* [opensource.com: Why I use Ingress Controllers to expose Kubernetes services](https://opensource.com/article/20/8/ingress-controllers-kubernetes) Kubernetes ingress controllers will make or break your cloud architecture.
* [blog.nody.cc: Verify your Kubernetes Cluster Network Policies: From Faith to Proof](https://blog.nody.cc/posts/2020-06-kubernetes-network-policy-verification/)
* [medium: How to setup Hetzner load balancer on a Kubernetes cluster](https://medium.com/@jmrobles/how-to-setup-hetzner-load-balancer-on-a-kubernetes-cluster-2ce79ca4a27b)
* [zhimin-wen.medium.com: Sticky Sessions in Kubernetes π](https://zhimin-wen.medium.com/sticky-sessions-in-kubernetes-56eb0e8f257d)
* [infoq.com: Kubernetes Ingress Is Now Generally Available](https://www.infoq.com/news/2020/09/kubernetes-ingress-ga/)
* [Learnk8s: Comparison of Kubernetes Ingress Controllers ππ](https://docs.google.com/spreadsheets/d/191WWNpjJ2za6-nbG4ZoUMXMpUK8KlCIosvQB0f-oq3k/edit#gid=907731238) How do you choose the *right* Kubernetes Ingress controller when: Not all Ingress controllers support UDP, Only Kong has a free LDAP integration, Nginx Ingress and HAProxy are the only two ingress without CRDs.
* [blog.alexellis.io: Get kubectl access to your private cluster from anywhere](https://blog.alexellis.io/get-private-kubectl-access-anywhere/)
* [jmrobles.medium.com: How to setup Hetzner load balancer on a Kubernetes cluster](https://jmrobles.medium.com/how-to-setup-hetzner-load-balancer-on-a-kubernetes-cluster-2ce79ca4a27b)
* [kubernetes.io: Scaling Kubernetes Networking With EndpointSlices](https://kubernetes.io/blog/2020/09/02/scaling-kubernetes-networking-with-endpointslices/) EndpointSlices are a new Kubernetes API that provides a scalable and extensible alternative to the Endpoints API.
* [medium: Create a Custom Annotation for the Kubernetes ingress-nginx Controller](https://medium.com/better-programming/creating-a-custom-annotation-for-the-kubernetes-ingress-nginx-controller-444e9d486192)
* [haproxy.com: Announcing HAProxy Kubernetes Ingress Controller 1.5 π](https://www.haproxy.com/blog/announcing-haproxy-kubernetes-ingress-controller-1-5/)
* [devclass.com: HAProxy Ingress Controller 1.5 introduces mTLS support, gives load balancing experts more power](https://devclass.com/2021/01/26/haproxy-ingress-controller-1_5/)
* [thenewstack.io: HAProxy Kubernetes Ingress Controller Moves Outside the Cluster](https://thenewstack.io/haproxy-kubernetes-ingress-controller-moves-outside-the-cluster/)
* [suse.com: NGINX Guest Blog: NGINX Kubernetes Ingress Controller π](https://www.suse.com/c/nginx-guest-blog-kubernetes-ingress-controller)
* [dustinspecker.com: iptables: How Kubernetes Services Direct Traffic to Pods](https://dustinspecker.com/posts/iptables-how-kubernetes-services-direct-traffic-to-pods) In this article you will learn how Kubernetes's kube-proxy uses iptables to direct traffic to pods randomly. You'll focus on the ClusterIP type of Kubernetes services.
* [blog.cloudflare.com: Moving k8s communication to gRPC](https://blog.cloudflare.com/moving-k8s-communication-to-grpc/)
* [tech2fun.net: K8s Nginx Ingress Handling TLS Traffic and Using Pod Readiness Probes](https://tech2fun.net/k8s-nginx-ingress-handling-tls-traffic-and-using-pod-readiness-probes/)
* [K8GB - Kubernetes Global Balancer](https://github.com/AbsaOSS/k8gb) - [openshift.com: K8GB - Kubernetes Global Balancer ](https://www.openshift.com/blog/openshift-commons-briefing-k8gb-kubernetes-global-balancer-with-yuri-tsarev-absa-and-paul-morie-red-hat)
* [altoros.com: Kubernetes Networking: How to Write Your Own CNI Plug-in with Bash](https://www.altoros.com/blog/kubernetes-networking-writing-your-own-simple-cni-plug-in-with-bash/)
* [Network Node Manager](https://github.com/kakao/network-node-manager) network-node-manager is a kubernetes controller that controls the network configuration of a node to resolve network issues of kubernetes. By simply deploying and configuring network-node-manager, you can solve kubernetes network issues that cannot be resolved by kubernetes or resolved by the higher kubernetes Version. Below is a list of kubernetes's issues to be resolved by network-node-manager. network-node-manager is based on kubebuilder v2.3.1.
* [getenroute.io: Drive API Security At Kubernetes Ingress Using Helm And Envoy π](https://getenroute.io/docs/ingress-filter-legos-secure-microservices-apis-using-helm-envoy/)
* [ithands-on.com: Kubernetes 101 : External services - ExternalName, DNS and Endpoints](https://www.ithands-on.com/2021/04/kubernetes-101-external-services.html)
* [ibm.com: Multizone Kubernetes and VPC Load Balancer Setup](https://www.ibm.com/cloud/blog/multizone-kubernetes-and-vpc-load-balancer-setup) Securely expose your Kubernetes app by setting up a Load Balancer for VPC in a different zone.
* [opensource.googleblog.com: Kubernetes: Efficient Multi-Zone Networking with Topology Aware Routing](https://opensource.googleblog.com/2020/11/kubernetes-efficient-multi-zone.html)
* [nbailey.ca: Domesticated Kubernetes Networking](https://nbailey.ca/post/k8s-networking/)
* [sookocheff.com: A Guide to the Kubernetes Networking Model π](https://sookocheff.com/post/kubernetes/understanding-kubernetes-networking-model/)
* [build.thebeat.co: A curious case of AWS NLB timeouts in Kubernetes](https://build.thebeat.co/a-curious-case-of-aws-nlb-timeouts-in-kubernetes-522bd88a3399) A debugging adventure that allowed us to solve the tail latencies our Kubernetes applications were experiencing when talking with our AWS NLB.
* [dzone: Multizone Kubernetes and VPC Load Balancer Setup](https://dzone.com/articles/multizone-kubernetes-and-vpc-load-balancer-setup) Securely expose your Kubernetes app by setting up a Load Balancer for VPC in a different zone.
* [ingressbuilder.jetstack.io ππ](https://ingressbuilder.jetstack.io) Ingress Builder allows users to select any annotation from the list of available controllers, to add to the ingress manifest.
* [itnext.io: Generating Kubernetes Network Policies Automatically By Sniffing Network Traffic π](https://itnext.io/generating-kubernetes-network-policies-by-sniffing-network-traffic-6d5135fe77db) This blog post is about an experiment to automate creation of Kubernetes Network Policies based on actual network traffic captured from applications running on a Kubernetes cluster - [code](https://github.com/mcelep/blog/tree/master/automated-networkpolicy-generation)
* [medium: Using nginx-ingress controller to restrict access by IP (ip whitelisting) for a service deployed to a Kubernetes (AKS) cluster](https://medium.com/@maninder.bindra/using-nginx-ingress-controller-to-restrict-access-by-ip-ip-whitelisting-for-a-service-deployed-to-bd5c86dc66d6)
* [openshift.com: gRPC or HTTP/2 Ingress Connectivity in OpenShift π](https://www.openshift.com/blog/grpc-or-http/2-ingress-connectivity-in-openshift)
* [inlets.dev: Fixing Ingress for short-lived local Kubernetes clusters](https://inlets.dev/blog/2021/07/08/short-lived-clusters.html)
* [nginx.com: How to Simplify Kubernetes Ingress and Egress Traffic Management](https://www.nginx.com/blog/how-to-simplify-kubernetes-ingress-egress-traffic-management/)
* [blog.teamhephy.info: Running Workflow Without Any LoadBalancer](https://blog.teamhephy.info/blog/posts/tutorials/running-workflow-without-any-loadbalancer.html)
* [blog.alexellis.io: Get a public LoadBalancer for your private Kubernetes cluster π](https://blog.alexellis.io/ingress-for-your-local-kubernetes-cluster/)
* [searchitoperations.techtarget.com: Differences between Kubernetes Ingress vs. load balancer](https://searchitoperations.techtarget.com/feature/Differences-between-Kubernetes-Ingress-vs-load-balancer) To manage Kubernetes cluster traffic, admins have a few choices. Compare Kubernetes Ingress vs. load balancers, as well as the NodePort and ClusterIP service types.
* [monzo.com: Controlling outbound traffic from Kubernetes](https://monzo.com/blog/controlling-outbound-traffic-from-kubernetes)
* [medium: Access Application Externally In Kubernetes Cluster using Load Balancer Service](https://medium.com/codex/access-application-externally-in-kubernetes-cluster-using-load-balancer-service-d1b7858d51) Learn how to create a Pod and how to create a Load Balancer service using Kubernetes cluster. And access the application from outside.
* [itnext.io: Why and How of Kubernetes Ingress (and Networking) π](https://itnext.io/why-and-how-of-kubernetes-ingress-and-networking-6cb308ca03d2)
* [techdozo.dev: gRPC load balancing on Kubernetes (using Headless Service)](https://techdozo.dev/grpc-load-balancing-on-kubernetes-using-headless-service/)
* [thenewstack.io: ZeroLB, a New Decentralized Pattern for Load Balancing](https://thenewstack.io/zerolb-a-new-decentralized-pattern-for-load-balancing/)
* [ungleich.ch: Making kubernetes kube-dns publicly reachable](https://ungleich.ch/u/blog/kubernetes-making-dns-publicly-reachable/)
* [ungleich.ch: Building Ingress-less Kubernetes Clusters](https://ungleich.ch/u/blog/kubernetes-without-ingress/)
* [thenewstack.io: Ingress Controllers: The More the Merrier](https://thenewstack.io/ingress-controllers-the-more-the-merrier/)
* [blog.teamhephy.info: Learn how to use the Nginx Ingress controller to serve traffic over SSH with TCP load balancing](https://blog.teamhephy.info/blog/posts/tutorials/running-workflow-without-any-loadbalancer.html)
* [levelup.gitconnected.com: Setting up Application Load Balancer (Ingress) for the Pods running in AWS EKS Fargate](https://levelup.gitconnected.com/setting-up-application-load-balancer-ingress-for-the-pods-running-in-aws-eks-fargate-519e20e97497)
* [NGINX Ingress Controller - v1.0.0](https://github.com/kubernetes/ingress-nginx/releases/tag/controller-v1.0.0) NGINX Ingress Controller v1.0.0 released today! The biggest change is the support to stable/v1 ingress object, and dropping support to v1beta1.
* [devopscube.com: Kubernetes Ingress Tutorial For Beginners](https://devopscube.com/kubernetes-ingress-tutorial/)
* [ystatit.medium.com: How to Change Kubernetes Kube-apiserver IP Address](https://ystatit.medium.com/how-to-change-kubernetes-kube-apiserver-ip-address-402d6ddb8aa2)
* [monzo.com: Controlling outbound traffic from Kubernetes](https://monzo.com/blog/controlling-outbound-traffic-from-kubernetes)
## Gateway API
* [gateway-api.sigs.k8s.io π](https://gateway-api.sigs.k8s.io/) Gateway API is an open source project managed by the SIG-NETWORK community. It's is a collection of resources that model service networking in Kubernetes. These resources - GatewayClass,Gateway, HTTPRoute, TCPRoute, Service, etc - aim to evolve Kubernetes service networking through expressive, extensible, and role-oriented interfaces that are implemented by many vendors and have broad industry support.
* [kubernetes.io: Evolving Kubernetes networking with the Gateway API](https://kubernetes.io/blog/2021/04/22/evolving-kubernetes-networking-with-the-gateway-api/)
* [thenewstack.io: Unifying Kubernetes Service Networking (Again) with the Gateway API π](https://thenewstack.io/unifying-kubernetes-service-networking-again-with-the-gateway-api/) The [Gateway API](https://gateway-api.sigs.k8s.io/), formerly known as the Services API and before that Ingress V2, was first discussed in detail β and in-person β at Kubecon 2019 in San Diego. There were already many well-known and [well-documented](https://dave.cheney.net/paste/ingress-is-dead-long-live-ingressroute.pdf) limitations of Ingress and Kubernetes networking APIs. The [Gateway API](https://www.youtube.com/watch?v=GiFQNevrxYA) was intended as a redo of these APIs, built on the lessons from Services, Ingress and the service mesh community.
## Multicloud communication for Kubernetes
* [developers.redhat.com: Use Skupper to connect multiple Kubernetes clusters π](https://developers.redhat.com/blog/2021/04/20/use-skupper-to-connect-multiple-kubernetes-clusters/) - [skupper.io](https://skupper.io/) Multicloud communication for Kubernetes. Skupper is a layer 7 service interconnect. It enables secure communication across Kubernetes clusters with no VPNs or special firewall rules. With Skupper, your application can span multiple cloud providers, data centers, and regions.
## Kubernetes Network Policy
* [howtoforge.com: Network Policy in Kubernetes π](https://www.howtoforge.com/kubernetes_network_policy/) By default, pods accept traffic from any source. A network policy helps to specify how a group of pods can communicate with each other and other network endpoints.
* [medium: How to Provision Network Policies in Kubernetes | AWS π](https://medium.com/avmconsulting-blog/exploring-network-policies-in-kubernetes-c8a3d8ed00cb)
* [learncloudnative.com: Kubernetes Network Policy](https://www.learncloudnative.com/blog/2020-10-07-network-policies)
* [bionconsulting.com: Kubernetes Network Policies](https://www.bionconsulting.com/blog/kubernetes-network-policies)
* [bionconsulting.com: Kubernetes Network Policies - Part 2](https://www.bionconsulting.com/blog/kubernetes-network-policies-part-2)
* [thenewstack.io: The Kubernetes Network Security Effect π](https://thenewstack.io/the-kubernetes-network-security-effect/) Kubernetes has a built-in object for managing network security: NetworkPolicy. While it allows the user to define the relationship between pods with ingress and egress policies, it is basic and requires very precise IP mapping of a solution β which changes constantly, so most users Iβve talked to are not using it.
* [faun.pub: Control traffic flow to and from Kubernetes pods with Network Policies](https://faun.pub/control-traffic-flow-to-and-from-kubernetes-pods-with-network-policies-bc384c2d1f8c)
* [openshift.com: Network Policies: Controlling Cross-Project Communication on OpenShift](https://www.openshift.com/blog/network-policies-controlling-cross-project-communication-on-openshift)
* [loft-sh.medium.com: Kubernetes Network Policies: A Practitionerβs Guide π](https://loft-sh.medium.com/kubernetes-network-policies-a-practitioners-guide-c9bb4cdd0dbc)
* [loft.sh: Kubernetes Network Policies: A Practitioner's Guide](https://loft.sh/blog/kubernetes-network-policies-a-practitioners-guide)
### Cilium
* [cilium.io π](https://cilium.io/) eBPF-based Networking, Observability, and Security
* [cilium.io: NetworkPolicy Editor: Create, Visualize, and Share Kubernetes NetworkPolicies π](https://cilium.io/blog/2021/02/10/network-policy-editor)
* [editor.cilium.io π](https://editor.cilium.io/) Learn how to create Network Policies for Kubernetes using an interactive playground
* [buoyant.io: Kubernetes network policies with Cilium and Linkerd](https://buoyant.io/2020/12/23/kubernetes-network-policies-with-cilium-and-linkerd)
* [itnext.io: Installing Cilium on Kubernetes in a fast and efficient way](https://itnext.io/installing-cilium-on-kubernetes-in-a-fast-and-efficient-way-dbcb79ce9699)
* [cilium.io: CNI Benchmark: Understanding Cilium Network Performance](https://cilium.io/blog/2021/05/11/cni-benchmark)
## Kubernetes Ingress Specification
- [Supporting the Evolving Ingress Specification in Kubernetes 1.18](https://kubernetes.io/blog/2020/06/05/supporting-the-evolving-ingress-specification-in-kubernetes-1.18/)
- [medium: Ingress service types in Kubernetes π](https://medium.com/faun/ingress-service-types-in-kubernetes-3e9b68b78307)
## Xposer Kubernetes Controller To Manage Ingresses
* [Xposer π](https://github.com/stakater/Xposer) A Kubernetes controller to manage (create/update/delete) Kubernetes Ingresses based on the Service
* Problem: We would like to watch for services running in our cluster; and create Ingresses and generate TLS certificates automatically (optional)
* Solution: Xposer can watch for all the services running in our cluster; Creates, Updates, Deletes Ingresses and uses certmanager to generate TLS certificates automatically based on some annotations.
## Software-Defined IP Address Management (IPAM)
- [IP Address Management (IPAM)](https://en.wikipedia.org/wiki/IP_address_management)
- [fusionlayer.com: Software-Defined IP Address Management (IPAM)](https://www.fusionlayer.com/products/ip-address-management-software-defined-ipam-infinity)
- Cloud computing and service automation are changing the way in which applications and data are being delivered and consumed. The existing 30-year-old networking model is failing to keep up with the automated service architectures and the Internet of Things (IoT) based on end-to-end automation.
- **To facilitate the migration to cloud-era computing, service providers and data centers must add networking into the automated service workflows.** This requires agility and elasticity that traditional networking products are not designed to provide. As IT environments of tomorrow involve a plethora of orchestrators and controllers spinning up services and applications inside shared networks, they all must be managed and provisioned by a unified solution authoritative for all network-related information.
## CNI Container Networking Interface
* [Kubernetes.io: Network Plugins](https://kubernetes.io/docs/concepts/extend-kubernetes/compute-storage-net/network-plugins/)
* [rancher.com: Container Network Interface (CNI) Providers](https://rancher.com/docs/rancher/v2.x/en/faq/networking/cni-providers/)
* [github.com/containernetworking π](https://github.com/containernetworking)
* [CNI](https://github.com/containernetworking/cni)
* [dzone: How to Understand and Set Up Kubernetes Networking π](https://dzone.com/articles/how-to-understand-and-setup-kubernetes-networking) Take a look at this tutorial that goes through and explains the inner workings of Kubernetes networking, including working with multiple networks.
* [medium: Container Networking Interface aka CNI](https://medium.com/@vikram.fugro/container-networking-interface-aka-cni-bdfe23f865cf)
* [itnext.io: Benchmark results of Kubernetes network plugins (CNI) over 10Gbit/s network (Updated: August 2020)](https://itnext.io/benchmark-results-of-kubernetes-network-plugins-cni-over-10gbit-s-network-updated-august-2020-6e1b757b9e49)
### List of existing CNI Plugins (IPAM)
- [Kubernetes Networking](https://kubernetes.io/docs/concepts/cluster-administration/networking/)
- Overlay Network plugins:
- [Flannel](https://github.com/coreos/flannel)
- [Weave-net](https://www.weave.works/docs/net/latest/overview/)
- Routed Network Plugins:
- [AWS-VPC](https://en.wikipedia.org/wiki/Amazon_Virtual_Private_Cloud)
- [kube-router](https://www.kube-router.io/)
- [Calico](https://www.projectcalico.org/)
- [Canal](https://docs.projectcalico.org/getting-started/kubernetes/flannel/flannel)
- [VMware-tanzu Antrea](https://github.com/vmware-tanzu/antrea)
- [IPAM](https://en.wikipedia.org/wiki/IP_address_management) modules:
- dhcp
- host-local
- Multi CNI plugins:
- [Damn](https://github.com/nokia/danm)
- [Multus](https://github.com/openshift/multus-cni)
- [CNI-Genie](https://github.com/cni-genie/CNI-Genie)
[](https://thenewstack.io/tigera-aims-ease-connectivity-pain-kubernetes/)
### Project Calico
* [tigera.io](https://www.tigera.io/)
* [Project Calico π](https://www.projectcalico.org/) Secure networking for the cloud native era
* [medium: Calico for Kubernetes networking: the basics & examples](https://medium.com/flant-com/calico-for-kubernetes-networking-792b41e19d69)
* [thenewstack.io: Tigera's Calico Aims to Ease Connectivity Pain with Kubernetes](https://thenewstack.io/tigera-aims-ease-connectivity-pain-kubernetes/)
* [projectcalico.org: Advertising Kubernetes Service IPs with Calico and BGP](https://www.projectcalico.org/advertising-kubernetes-service-ips-with-calico-and-bgp/)
* [mhmxs.blogspot.com: Autoscaling Calico Route Reflector topology in Kubernetes](https://mhmxs.blogspot.com/2020/12/autoscaling-calico-route-reflector.html)
## DNS Service with CoreDNS
- [medium: How to Autoscale the DNS Service in a Kubernetes Cluster](https://medium.com/faun/how-to-autoscale-the-dns-service-in-a-kubernetes-cluster-cbb46ae89678)
- [thenewstack.io: Supercharge CoreDNS with Cluster Addons π](https://thenewstack.io/supercharge-coredns-with-cluster-addons/)
- [sysdig.com: How to monitor coreDNS π](https://sysdig.com/blog/how-to-monitor-coredns/) The most common problems and outages in a Kubernetes cluster come from coreDNS, so learning how to monitor coreDNS is crucial.
## Kubernetes Node Local DNS Cache
- [NodeLocal DNSCache](https://github.com/kubernetes/enhancements/blob/master/keps/sig-network/20190424-NodeLocalDNS-beta-proposal.md)
- [Kubernetes Node Local DNS Cache](https://povilasv.me/kubernetes-node-local-dns-cache/)
## Kubernetes Sidecars
* [banzaicloud.com: Sidecar container lifecycle changes in Kubernetes 1.18 π](https://banzaicloud.com/blog/k8s-sidecars/)
* [medium: Delaying application start until sidecar is ready](https://medium.com/@marko.luksa/delaying-application-start-until-sidecar-is-ready-2ec2d21a7b74) Taking advantage of a peculiar Kubernetes implementation detail to block containers from starting before another container starts.