Kubernetes Demystified

“When you look into it, Kubernetes isn’t that complicated after all”

Transcript

1. “WHEN YOU LOOK INTO IT, KUBERNETES ISN’T THAT COMPLICATED AFTER ALL” WYLIIKITCAA
2. WHAT IS KUBERNETES? CLUSTER STATE STORE (AND MANAGER)
3. WHAT IS KUBERNETES? DESIRED STATE CLUSTER
4. WHAT IS KUBERNETES? “I NEED A CONTAINER RUNNING NGINX” Pick feasible nodes Update their desired state Get the current state
5. WHAT IS KUBERNETES? “I NEED A CONTAINER RUNNING NGINX” Pick feasible nodes Update their desired state Get the current state
6. HOW DO I SET THE DESIRED STATE? apiVersion: v1 kind: Pod metadata: name: nginx spec: containers: - name: nginx image: nginx:1.7.9 ports: - containerPort: 80
7. HOW DO I SET THE DESIRED STATE? $ kubectl create -f pod-nginx.yaml
8. WHAT IS KUBERNETES? “I NEED A CONTAINER RUNNING NGINX” Pick feasible nodes Update their desired state Get the current state
9. HOW DOES KUBERNETES SELECT THE FEASIBLE NODES? CONTROLLERS
10. DEPLOYMENT STATEFUL SET DAEMON SET WORKLOAD CONTROLLERS
11. DEPLOYMENT Declarative updates Rolling back Scaling Creates ReplicaSets WORKLOAD CONTROLLERS
12. STATEFUL SET Guaranteed order and uniqueness Persistant storage Stable, unique network identifiers WORKLOAD CONTROLLERS
13. DAEMON SET Running on all nodes WORKLOAD CONTROLLERS
14. LABELS
15. AFFINITY TAINT Node selectors Required/preferred Conditions Eviction TAINT AND AFFINITY
16. WHAT IS KUBERNETES? “I NEED A CONTAINER RUNNING NGINX” Pick feasible nodes Update their desired state Get the current state
17. THE DESIRED STATE
18. ETCD Distributed key/value store Like a directory tree (/etc) JSON/REST API Uses a Discovery URL Needs at least 3 nodes for consensus
19. WHAT IS KUBERNETES? “I NEED A CONTAINER RUNNING NGINX” Pick feasible nodes Update their desired state Get the current state
20. KUBELET
22. WHAT IS KUBERNETES? “I NEED A CONTAINER RUNNING NGINX” Pick feasible nodes Update their desired state Get the current state