Kubernetes 1.3 - Highlights
3 likes1,058 views
Kubernetes 1.3 introduces several new features including cluster federation, petset for stateful services, and init containers running before main containers. It supports enhanced scalability, integrating the rkt container runtime alongside Docker, and features minikube for local development. Key functionalities include stable network identities for services and improvements in pod startup times.
Kubernetes 1.3 - Highlights
- 1. Kubernetes 1.3 What’s New Matt Bates Co-founder @JetstackHQ
- 4. Headlines of 1.3 - Cluster Federation - PetSet - Init Containers - Rktnetes 1.0 - Scalability - Minikube
- 5. Init Containers (#23567) – Alpha feature – Run container(s) before the long-running main pod container(s) are launched – Executed in sequential order – Only if init containers succeed do the main container(s) start – Use cases: – download files / clone repos – write out config files – etc init-1 init-2 main-container
- 6. Stateful services (1.2) - ReplicaSets (nee controllers) ensure N replicas of a pod template exist - Only attribute that differs between pods is the name - Therefore same volume(s) - Pods have no stable network identity other than an assigned pod IP - e.g. no fixed and predictable hostname - Best for ‘shared-nothing, zero-coordination systems’ Photo credit: http://delectabledeliciousness.blogspot.co.uk
- 7. PetSet (#18016) – New Alpha resource (apps/v1alpha1) – Stable and unique identity associated with that instance of the storage – Consistent network identity – Predictable number of instances to ensure that systems can form a quorum – Ability to migrate from node to node with stable network identity (DNS name) – Scale up/down in a controlled fashion
- 8. PetSet (#18016) PetSet pet-0. pet.default... PetSet Controller (KCM) PV-0 PVC-0 API Server Watches Creates claim from template BindsMounts Creates and waits until ready Service 1:1 mapping
- 9. PetSet (#18016) PetSet pet-0. pet.default... PetSet Controller (KCM) PV-0 PVC-0 API Server Service pet-1. pet.default... PV-1 PVC-1 pet-2. pet.default... PV-2 PVC-2
- 10. eu-west-1beu-west-1a eu-west-1c Recap: Cross-AZ clusters Cross-AZ clusters (Ubernetes ‘Lite’) baked into 1.2 worker worker worker Control Plane $ kubectl describe node worker1 ... failure-domain.beta.kubernetes.io/ region=eu-west1 failure-domain.beta.ku bernetes.io/ zone=eu-west1-a ...
- 11. Cluster Federation/Ubernetes (#19313) eu-central-1eu-west-1 worker worker worker Cluster A Control Plane worker worker worker Cluster B Control Plane
- 12. Cluster Federation/Ubernetes (#19313) eu-central-1eu-west-1 worker worker worker Cluster A Control Plane worker worker worker Cluster B Control Plane Federation Control PlaneFederation Controller Manager Federation API Server
- 13. Cluster Federation/Ubernetes (#19313) – Focused on Federated Services at this stage – Create a Service at the Federation API Server: – Creates matching Kubernetes Services in every cluster – Monitors the health of service “shards” – Manages DNS records in a public DNS provider (ie Google Cloud DNS or AWS Route 53) – Note: backend Pods are currently added directly against the cluster API endpoints
- 14. Federation Control PlaneFederation Controller Manager Federation API Server DNS Provider (Route 53, Google DNS) kube-dnskube-dns myservice.mynamespace.myfederation myservice.mynamespace.myfederation.svc.jetstack.net myservice.jetstack.net myservice.mynamespace.myfederation.svc. eu-west-1.jetstack.net myservice.mynamespace.myfederation.svc. eu-central-1.jetstack.net
- 15. Federation Control PlaneFederation Controller Manager Federation API Server DNS Provider (Route 53, Google DNS) kube-dnskube-dns myservice.jetstack.net eu-west-1.jetstack.net eu-central-1.jetstack.net
- 16. rktnetes 1.0 – Kubernetes was built to ultimately be container runtime-agnostic – First stable release that integrates the CoreOS rkt runtime, that can be used in-place of Docker – Why Rkt? – rkt implements the open App Container Spec – Compatibility with init systems such as systemd (nspawn) – Ability to launch VMs in pods for greater isolation guarantee (using LKVM stage1)
- 17. Scalability – Supports 2000-node clusters with decreased end-to-end pod startup time – Under the bonnet, uses Protocol Buffer-based serialization in the API instead of JSON
- 18. Minikube – Minikube starts a single node kubernetes cluster locally for purposes of development and testing. – Packages and configures a Linux VM, Docker and all Kubernetes components, optimized for local development. – Supports: – DNS – NodePorts – ConfigMaps and Secrets – Dashboards – Does not support cloud-provider functionality (LoadBalancers, PersistentVolumes, Ingress)
- 20. Matt Bates bates@jetstack.io | @mattbates25 www.jetstack.io hello@jetstack.io @JetstackHQ meetup.com/contain