# Kubernetes Workshop --- # Agenda - What is Kubernetes? - What does it do? - How does it work? - lots of demos --- # What is Kubernetes (k8s)? --- A portable, extensible, open-source platform for managing containerized workloads and services, that facilitates both declarative configuration and automation. https://kubernetes.io/docs/concepts/overview/ --- ## What the %^$# does that mean? --- A container orchestrator. --- # What does it do? --- It allows us to to manage our applications as containers, and orchestrate them by leveraging fancy rules, for example auto-healing, auto-scaling and rolling updates. --- - Provides a runtime environment for containers - Scales and load balances containers - Abstracts away the underlying infrastructure - Monitors and health checks containers - Updates containers - Provides service discovery and exposure --- # But why should I care? --- We care about this because with it, we can feed it our containerized application and be sure they will be run with minimal manual intervention. --- Pros - Using Kubernetes and its ecosystem can improve a team's productivity - Helps making our application more stable/bulletproof - Lots of community and professional support --- Cons - Steep Learning curve - Administration overhead, especially if maintaining own cluster - Not worth it for smaller applications/projects --- # How does it work? --- We run a number of services on all the machines (nodes) which make part of our cluster. --- ## High level overview  https://kubernetes.io/docs/concepts/architecture/ --- ## Kubectl To interact with the cluster, we use [kubectl](https://kubernetes.io/docs/tasks/tools/install-kubectl/) ``` $ kubectl get nodes NAME STATUS ROLES AGE VERSION k8s-1 Ready master 17h v1.25.4 k8s-2 Ready <none> 17h v1.25.4 k8s-3 Ready <none> 17h v1.25.4 ``` --- ## alias k = kubectl :) --- ``` $ k get nodes NAME STATUS ROLES AGE VERSION k8s-1 Ready master 17h v1.25.4 k8s-2 Ready <none> 17h v1.25.4 k8s-3 Ready <none> 17h v1.25.4 ``` --- ## Kubernetes objects Persistent entities in the Kubernetes ecosystem. Such entities represent the state of the cluster, and are represented in YAML format. ``` --- apiVersion: ... kind: ... metadata: name: ... spec: ... ``` --- # Pods - Smallest deployable units that can be managed by Kubernetes - Groups 1 or more containers - Meant to run a single instance of our application https://kubernetes.io/docs/concepts/workloads/pods/ --- # Demo Running a workload in a pod and inspecting it --- # Deployments - Provides updates to Pods - Describe a desired state - Used to run stateless workloads https://kubernetes.io/docs/concepts/workloads/controllers/deployment/ --- # Demo Running a stateless workload --- # Updating Deployments - Provide rolling updates to pods - Ensure pods are available at all times, even when failing updates - Provide facilities to roll back deployments gone wrong https://kubernetes.io/docs/concepts/workloads/controllers/deployment/ --- # Demo Updating a stateless workload --- # Statefulsets - Manage applications with state, like databases - Provide unique network identifier - Provide stable and persistent storage - Ordered, graceful deployment and scaling https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/ --- # Demo Running a stateful workload --- # ConfigMap - Store non-confidential data in key-value pairs - Pods can consume and use data from ConfigMaps - Used to decouple environment config from container images https://kubernetes.io/docs/concepts/configuration/configmap/ --- # Demo Configuring a workload with a configmap --- # Secrets - Store small amounts of sensitive data such as password, token or keys - Like configmaps, pods can consume values from secrets - Data is encoded with base64 (😱) https://kubernetes.io/docs/concepts/configuration/secret/ --- # Demo Configuring a workload with a secret --- # Common issues - crashloopbackoff (CLBO) - imagepull backoff --- # Tools K8s tools used by Rockhoppers: - Sealed Secrets - Kustomize - ArgoCD --- # Q&A --- # Resources - [kubernetes.io](https://kubernetes.io) - [Cloud Native Devops with Kubernetes](https://www.amazon.com/Cloud-Native-DevOps-Kubernetes-Applications/dp/1492040762/ref=sr_1_1?crid=3F7BFMTNBRUL1&dchild=1&keywords=cloud+native+devops+with+kubernetes&qid=1607864321&sprefix=cloud+native+devops%2Caps%2C267&sr=8-1) - [Kubernetes Up and Running](https://www.amazon.com/Kubernetes-Running-Dive-Future-Infrastructure/dp/1492046531/ref=sr_1_1?dchild=1&keywords=kubernetes+up+and+running&qid=1607864298&sr=8-1) - [CKA course](https://github.com/kodekloudhub/certified-kubernetes-administrator-course) - [The Almighty Pause Container](https://www.ianlewis.org/en/almighty-pause-container) - [kubeadm](https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/) - [k8s workshop](https://github.com/maiku1008/k8s-workshop) --- ## The end?