# Getting started ## Basic terms: system parts * Kubernetes: the whole orchestration system (K8s "k-eights" or Kube for short) * Kubectl: CLI to configure Kubernetes and manage apps (using "cube control" official pronunciation) * Node: single server in the Kubernetes cluster * Kubelet: Kubernetes agent running on nodes * Control plane: set of containers that manage the cluster * Includes API server, scheduler, controller manager, etcd and more * Sometimes called the "master" ## Installing Kubernetes locally * Kubernetes is a series of containers, CLI's and configurations * Many ways to install: * MacOS: Docker Desktop - Enable in Settings. Sets up everything inside Docker's existing Linux VM * Runs, configures Kubernetes Master containers * Manages `kubectl` install and certificates * Easily install, disable and remove from Docker GUI * Docker Toolbox on Windows - MiniKube. Uses VirtualBox to make Linux VM * Doesn't install `kubectl`, has to be installed separately * Your own Linux host or VM - MicroK8s. Installs Kubernetes right on the OS * Uses snap (rather apt or yum) for install. * Control MicroK8s service via `microk8s.` commands * `kubectl` accessible via `microk8s.kubectl` * Add an alias to your shell (.bash\_profile): \ `alias kubectl=microk8s.kubectl` * Kuberneters in a Browser * * katacoda.com ## Kubernetes Container Abstractions * **Pod**: one or more containers running together on one node. Basic unit of deployment. Containers are always in pods. * **Controller**: for creating / updating pods and other objects. Controllers manage pods, you almost never manage pods yourself. There are many types of Controllers, including `Deployment`, `ReplicaSet`, `StatefulSet`, `DaemonSet`, `Job`, `CronJob`, etc. * **Service**: network endpoint to connect to a pod. * **Namespace**: Filtered group of objects in cluster. * **Secrets**, **ConfigMaps**, etc. ## Kubernetes Run, Create and Apply * Kubernetes is evolving, and so is the CLI * We get 3 ways to create pods from the kubectl CLI * > `kubectl run` (changing to be only for pod creation) * > `kubectl create` (create some resources via CLI or YAML) * > `kubectl apply` (create / update anything via YAML) ### Basic commands * `kubectl version` - shows a version of Client and Server * `kubectl cluster-info` * `kubectl run my-nginx --image nginx` - this will create a pod, replica set and a deployment * `kubectl get pods` - get current pods * `kubectl get all` - get all components * `kubectl delete deployment my-nginx` - delete named deployment ### Scaling ReplicaSets * Start new deployment for one replica/pod `kubectl run my-apache --image httpd` * Scale deployment `kubectl scale deploy/my-apache --replicas 2` `kubectl scale deployment my-apache --replicas 2` (these are same commands) ### Inspecting Deployments * Get logs `kubectl logs deployment my-apache` * Get logs from pods with a given label `kubectl logs -l run=my-apache` * Stern for Kubernetes can be used to tail logs from multiple pods () `brew install stern` `stern pod-query` * Get pod info `kubectl describe pod/` (pod-id can be obtained with kubectl get pods)\` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://notebook.iuriioapps.com/containers-and-microservices/kubernetes/getting-started.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.