10/23: Kubernetes extended lunch session.

[shimmerjs]

this was mostly a workshop, so my notes are sparse.

kubernetes extended lunch session

k8s basics

kubectl cli basics

k8s API primitives

kind apiversion metadata spec status

node

• host machine. vm/bare metal/whatever.

pod

• collection of colocated pods. basic unit of kubernetes
• scheduled to be run on nodes. can force certain node execution using labels.

observations: automatic health checks / container life cycle async fulfillment declarative spec

service

• establish a single endpoint for a collection of replicated pods, distributing inbound traffic based on label selectors

• in our k8s modeling language they reprsent a load balancer. many many implementations (nginx, etc)

deployment

• A deployment helps you specify container runtime requirements (in terms of pods)
• A deployment spec contains a pod spec

replicaSet

• The API allows for watch operations (in addition to get, set, list) AUTO SCALING
• ReplicaSets provide lifecycle management for pod resources
• Deployments create ReplicaSets to manage pod replication per rollout (per change in podspec: image:tag, environment vars)

arch

• statefulness of k8s is etcd
  • distributed kvs
  • raft consensus protocol
• kubernetes api
  • gatekeeper for etcd

kube dns kube proxy kube controllers - regulate declarative nature of the platform state, reconsiling imbalances via a basic control loop. can implement custom controllers.

additional reading

https://www.gitbook.com/book/ramitsurana/awesome-kubernetes/details