1. Why Helm Is Needed One important design philosophy in Kubernetes is declarative operation. Users change the system by setting the system’s expected state. For example, the current replica count is 2 and it needs to be adjusted to 3. The declarative way is to modify the replica count in

1. What Is kubectl kubectl is the command-line tool for Kubernetes. It interacts with the cluster through the API server. 2. Configuring kubectl kubectl can be configured through ~/.kube/config to connect to one or more clusters. For details on how to configure it, see: Configure Access to Multiple Clusters. If you need to configure a remote cluster, see: Building a Remote Kubernetes Development Environment.

1. Cluster 1.1 Master The Master is responsible for managing and maintaining Kubernetes cluster information, dispatching tasks to Nodes, and receiving feedback. The components running on the Master include kube-apiserver, kube-scheduler, kube-controller-manager, cloud-controller-manager, and so on. 1.2 Node A Node carries the cluster workload; it can be a physical machine or a virtual machine.

Minikube is a single-node distribution of Kubernetes, suited to product evaluation and day-to-day development. Here we use Minikube to build a development environment: Kubernetes runs on a CentOS cloud server, and development happens remotely from a local OS X machine. 1. Install Minikube on the Cloud Server On the Minikube

1. Kubectl Basic Commands 1.1 Creating Objects 1 2 3 4 5 6 7 8 # Create resources; a remote URL also works kubectl create -f ./my.yaml # Create resources from multiple files kubectl create -f ./my1.yaml -f ./my2.yaml # Create resources using all manifest files in a directory kubectl create -f .