Marc Sluiter - 15 Kubernetes Features in 15 Minutes
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The document outlines 15 key features of Kubernetes, a container orchestration platform initiated by Google in 2014. It discusses the architecture, including components such as pods, replicasets, deployments, and services, as well as functionalities like autoscaling and jobs. It emphasizes its open-source nature and the growing community support surrounding Kubernetes.
Marc Sluiter - 15 Kubernetes Features in 15 Minutes
- 1. @slintes#Devoxx #Kubernetes 15 Kubernetes Features in 15 Minutes Marc Sluiter Luminis Technologies
- 2. @slintes#Devoxx #Kubernetes Who am I? • Software Engineer @ Luminis Technologies • Java, Go,Angular2 • Working on • Amdatu • INAETICS • CloudRTI
- 3. @slintes#Devoxx #Kubernetes Kubernetes • Greek for "helmsman" or “pilot" • schedules, runs and manages containers in a cluster of virtual or physical machines • declarative approach: • try permanently to reach the declared cluster state
- 4. @slintes#Devoxx #Kubernetes Kubernetes • started by Google in 2014 • based on over 10 years experience (“Borg”) • first release in Juli 2015 • donated to Cloud Native Computing Foundation • 100% Open Source • Go
- 5. @slintes#Devoxx #Kubernetes #1 Pods • smallest deployable unit • small group of tightly coupled containers • shared network and data volumes • routable IP address • mortal!
- 6. @slintes#Devoxx #Kubernetes #2 ReplicaSets • run x copies (replicas) of a pod • start or kill pods if necessary • handle pod failures • health checks
- 7. @slintes#Devoxx #Kubernetes #3 Deployments • contains declaration of your application • which containers (image / tag) • environment variables • data volumes • defines number of replicas • creates ReplicaSets, which in turn create Pods
- 8. @slintes#Devoxx #Kubernetes Deployments cont. • rolling updates:
- 9. @slintes#Devoxx #Kubernetes #4 Services • pods are mortal! • services provide a permanent virtual IP and DNS name • proxy traffic to selected pods • simple load balancing including session affinity
- 10. @slintes#Devoxx #Kubernetes #5 Ingress • expose services to the outside world • map URLs to services • SSL termination • needs ingress provider
- 11. @slintes#Devoxx #Kubernetes #6 Namespaces • Namespaces group kubernetes resources (pods, replicasets, deployments, …) • by default everything is in the “default” namespace • create namespaces for your environments (e.g. test, staging, production) and / or tenants • restrict access to specific namespaces for k8s users • namespaces can have separated networks (depends on network provider)
- 12. @slintes#Devoxx #Kubernetes #7 Clusters • a cluster is a set of virtual or physical machines (nodes), running a k8s master and one or more k8s worker nodes • cluster federation: • run a federation master, which knows all your clusters • run your apps distributed across clusters, e.g. across Amazon / Google / … regions
- 13. @slintes#Devoxx #Kubernetes #8 Secrets and ConfigMaps • separate your application code (= images) and configuration • both Secrets and ConfigMaps are key-value-pairs • use Secrets for binary values (e.g. certificates, keys) • use ConfigMaps for string values • both can be read by the container via environment variables or mapped into a data volume e.g. like property files
- 14. @slintes#Devoxx #Kubernetes #9 Data Volumes • map directories into containers • multiple containers in one pod share the same volumes • many volume types: • empty directory, host directory, Google Persistent Disk,Amazon Blob Store, NFS, glusterfs, rdb, cephs, git repository, … • can be preconfigured by cluster admins for easier usage by cluster users
- 15. @slintes#Devoxx #Kubernetes #10 PetSets • a Pet is a stateful pod • a PetSet has a scalable number of Pets • a Pet is bound to a dynamically created data volume • that data volume will never be deleted automatically • the Pet is bound to the same volume on a restart
- 16. @slintes#Devoxx #Kubernetes #11 Jobs • sometimes you need to run short living tasks • a Job ensures that a container which executes such a task runs successfully exactly once (ore more times) • retry on failure • ScheduledJobs can be started at specific times (like cron)
- 17. @slintes#Devoxx #Kubernetes #12 DaemonSets • DaemonSets run pods on all (or a selected set of) nodes in the cluster • useful for running containers for logging and monitoring
- 18. @slintes#Devoxx #Kubernetes #13 Autoscaling • Horizontal Pod Autoscaling • scales ReplicaSets based on pod’s CPU usage or app- provided metrics • Cluster Autoscaling • scale the number of nodes in your cluster based on CPU and memory usage • depends on cloud provider
- 19. @slintes#Devoxx #Kubernetes #14 API • every functionality is provided via a REST API • easy integration in your existing workflows (continuous delivery) • command line tool “kubectl” (uses the REST API internally)
- 20. @slintes#Devoxx #Kubernetes #15 Community! • constantly growing community • active on Stackoverflow, Google Groups and Slack • many contributors from many companies • KubeCon conference
- 24. @slintes#Devoxx #Kubernetes Kubernetes architecture • Master • API server • Controller • Scheduler • Workers • Kubelet • Proxy • State only in etcd!