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.

1. Kubernetes 1.3
What’s New
Matt Bates
Co-founder @JetstackHQ

2. 5000+
COMMITS
350+
CONTRIBUTORS

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)

19. More Hidden Gems..
https://blog.jetstack.io/blog/kubernetes-1-3-hidden-gems

20. Matt Bates
bates@jetstack.io | @mattbates25
www.jetstack.io
hello@jetstack.io
@JetstackHQ
meetup.com/contain