However, let's take a step back and try to understand why the above is needed for containers to run. The network configuration happens lightning fast in the background. Both containers share the same networking namespace and can see each other on localhost.An IP address is assigned to the pod, and the ports are shared between the two containers.The pod gets its own network namespace on the node.When deployed, the following things happen: Spec : containers : - name : container - 1 image : busyboxĬommand : - name : container - 2 image : nginx In this example, you have a pod with an Nginx container and another with busybox: Let's consider a main container hosting the application and another running alongside it. How Linux network namespaces work in a pod

In this article, you will focus on the first three points, starting with intra-pod networking or container-to-container communication. Can the pod receive traffic external to the cluster?.Can the pod reach services? And are the services load balancing requests?.Can the pod reach other pods in the cluster?.How do you make sure that containers in the same pod behave as if they are on the same host?.In satisfying those constraints, you will have to solve the following challenges: Instead, they describe the properties of the cluster network in general terms. Those requirements don't restrict the implementation to a single solution. Each pod has its own IP address (IP-per-Pod), and every other pod can reach it at that same address.Any program running on a cluster node should communicate with any pod on the same node without using NAT.A pod in the cluster should be able to freely communicate with any other pod without the use of Network Address Translation (NAT).The Kubernetes networking model defines a set of fundamental rules: Intercepting and rewriting traffic with Netfilter and Iptablesīefore diving into the details on how packets flow inside a Kubernetes cluster, let's first clear up the requirements for a Kubernetes network.Tracing pod to pod communication on different nodes.Tracing pod to pod traffic on the same node.The Pod network namespace is connected to an ethernet bridge.Inspecting pod to pod traffic in the cluster.The pod is assigned a single IP address.The pause container creates the network namespace in the pod.How Linux network namespaces work in a pod.Starting from the initial web request and down to the container hosting the application. TL DR: In this article, you will learn how packets flow inside and outside a Kubernetes cluster.

Ssh tunnel to kubernetes pod