Objectives Learn about Kubernetes Pods. Learn about Kubernetes Nodes. Troubleshoot deployed applications. Kubernetes Pods A Pod is a group of one or more application containers (such as Docker) and includes shared storage (volumes), IP address and information about how to run them. When you created a Deployment in Module 2, Kubernetes created a Pod to host your application instance. A Pod is a Kubernetes abstraction that represents a group of one or more application containers (such as Docker), and some shared resources for those containers.

Production-Grade Container Orchestration

Understand advanced ways to adapt your Kubernetes cluster to the needs of your work environment.

Production-Grade Container Orchestration

Labels are key/value pairs that are attached to objects such as Pods. Labels are intended to be used to specify identifying attributes of objects that are meaningful and relevant to users, but do not directly imply semantics to the core system. Labels can be used to organize and to select subsets of objects. Labels can be attached to objects at creation time and subsequently added and modified at any time.

Production-Grade Container Orchestration

In robotics and automation, a control loop is a non-terminating loop that regulates the state of a system. Here is one example of a control loop: a thermostat in a room. When you set the temperature, that's telling the thermostat about your desired state. The actual room temperature is the current state. The thermostat acts to bring the current state closer to the desired state, by turning equipment on or off.

Using kubeadm, you can create a minimum viable Kubernetes cluster that conforms to best practices. In fact, you can use kubeadm to set up a cluster that will pass the Kubernetes Conformance tests. kubeadm also supports other cluster lifecycle functions, such as bootstrap tokens and cluster upgrades. The kubeadm tool is good if you need: A simple way for you to try out Kubernetes, possibly for the first time. A way for existing users to automate setting up a cluster and test their application.

This page describes how kubelet managed Containers can use the Container lifecycle hook framework to run code triggered by events during their management lifecycle. Overview Analogous to many programming language frameworks that have component lifecycle hooks, such as Angular, Kubernetes provides Containers with lifecycle hooks. The hooks enable Containers to be aware of events in their management lifecycle and run code implemented in a handler when the corresponding lifecycle hook is executed.

Distributed systems often have a need for leases, which provide a mechanism to lock shared resources and coordinate activity between members of a set. In Kubernetes, the lease concept is represented by Lease objects in the coordination.k8s.io API Group, which are used for system-critical capabilities such as node heartbeats and component-level leader election. Node heartbeats Kubernetes uses the Lease API to communicate kubelet node heartbeats to the Kubernetes API server.