Getting Started with Kubernetes 2020-6-11

If you’re working with just a few containers, managing them is not too complicated. But what if you have hundreds or thousands? Think about having to handle multiple upgrades for each container, keeping track of container and node state, available resources, and more. That’s where Kubernetes comes in. Kubernetes is an open source container management platform that helps you run containers at scale. This talk will cover Kubernetes components and show how to run applications on it.

Transcript

1. Getting Started with Kubernetes Tiffany Jernigan Senior Developer Advocate VMware tiffanyfayj
2. T I F F A N Y F A Y J DOCKER People started containerizing applications
3. T I F F A N Y F A Y J Containers made it easy to build and scale cloud-native applications
4. T I F F A N Y F A Y J People needed an easier way to manage large clusters with many containers
5. T I F F A N Y F A Y J T I F F A N Y F A Y J
6. T I F F A N Y F A Y J Open source container management platform Helps you run containers at scale Gives you primitives for building modern applications WHAT IS KUBERNETES?
7. T I F F A N Y F A Y J A SINGLE EXTENSIBLE API SCALE PERFORMANCE BREADTH
8. T I F F A N Y F A Y J
9. T I F F A N Y F A Y J ON-PREMISES CLOUD KUBERNETES CAN BE RUN ANYWHERE
10. CONCEPTS T I F F A N Y F A Y J
11. T I F F A N Y F A Y J CLUSTER COMPONENTS
12. T I F F A N Y F A Y J NODES • When you deploy Kubernetes, you get a cluster. These clusters consist of nodes. • Virtual or physical machines • Node Types • Control Plane/Master • Worker
13. T I F F A N Y F A Y J NODES API server controller manager scheduler etcd cloud controller manager kubelet kube-proxy container runtime control plane worker
14. T I F F A N Y F A Y J CONTROL PLANE API server controller manager scheduler etcd cloud controller manager
15. T I F F A N Y F A Y J WORKER NODES kubelet kube-proxy container runtime
16. T I F F A N Y F A Y J OBJECTS
17. T I F F A N Y F A Y J OBJECTS Pods • Basic execution unit of a Kubernetes application • Will not reschedule on failure Deployment • Allows scaling, rolling updates, rollbacks • Delegates pod management to ReplicaSets ReplicaSet • Maintains a stable set of replica Pods running at any given time
18. T I F F A N Y F A Y J OBJECTS StatefulSet • Used to manage stateful applications • Manages deployment DaemonSet • Creates an instance of a pod on each worker node Job • Runs pod(s) until completion CronJob • Creates Jobs on a repeating schedule
19. T I F F A N Y F A Y J SERVICES
20. T I F F A N Y F A Y J SERVICES • Services give us a stable endpoint to connect to a pod or a group of pods • Maps a fixed IP address to a logical group of pods • Different types: • ClusterIP, NodePort, LoadBalancer, ExternalName • There are more kinds and flavors of services, but we won’t get into those today
21. T I F F A N Y F A Y J BASIC SERVICE TYPES • ClusterIP (default) • A virtual IP address is allocated for the service (internal private range) • This IP is only reachable from inside the cluster • NodePort • Port allocated for the service (in 30000-32767 range) • Port is available on all node • LoadBalancer • External LB allocated (typically a cloud LB) • Typically costs a little money
22. T I F F A N Y F A Y J NETWORKING
23. T I F F A N Y F A Y J KUBERNETES NETWORK MODEL • TL;DR: our cluster (nodes and pods) is one big flat IP network • In detail: ⁃ all nodes must be able to reach each other, without NAT ⁃ all pods must be able to reach each other, without NAT ⁃ pods and nodes must be able to reach each other, without NAT ⁃ each pod is aware of its IP address (no NAT) • Kubernetes doesn't mandate any other particular implementation
24. T I F F A N Y F A Y J CONTAINER NETWORK INTERFACE (CNI) • Has a well-defined specification for network plugins https://github.com/containernetworking/cni/blob/master/SP EC.md#network-configuration • When a pod is created, Kubernetes delegates the network setup to CNI plugins (it can be a single plugin, or a combination of plugins, each doing one task)
25. T I F F A N Y F A Y J SECURITY
26. T I F F A N Y F A Y J SECURITY • Namespaces • Service accounts • Role-based access control (RBAC) • Secrets • And there’s a lot more • https://kubernetes.io/docs/reference/access-authn-authz/
27. T I F F A N Y F A Y J COMMUNICATION WITH K8S API • kubectl • CLI tool used to interface with the Kubernetes API • ~/.kube/config • Kubeconfig file is used for securely accessing your cluster
28. DEMO T I F F A N Y F A Y J
29. T I F F A N Y F A Y J SOME OTHER THINGS TO LOOK INTO • ConfigMaps • Volumes • Autoscaling • Role-based access control (RBAC) • Secrets
30. T I F F A N Y F A Y J A FEW TOOLS TO MANAGE STACKS • Shell scripts invoking kubectl • YAML resource manifests committed to a repo • Kustomize (YAML manifests + patches applied on top) https://github.com/kubernetes-sigs/kustomize • Helm (YAML manifests + templating engine) https://github.com/kubernetes/helm • K14s https://k14s.io/
31. T I F F A N Y F A Y J LINKS AND RESOURCES • https://kubernetes.io/ • https://tanzu.vmware.com/ • https://container.training/ - @jpetazzo’s awesome workshops • https://kubernetes.io/community/ - Slack, Google Groups, meetups • Free Training: • https://kube.academy/ • https://kubernetes.io/docs/tutorials/ • https://labs.play-with-k8s.com/
32. tiffanyfayj Special thanks to: Jérôme Petazzoni @jpetazzo THANK YOU!