Big Picture

Question 1

A K8s cluster is made up of a bunch of…

Answer 1

linux nodes, some of which constitute the control plane and the others as worker nodes

Question 2

control plane consists of…

Answer 2

1. etcd
2. api server (nexus, ‘grand central station’)
3. scheduler

Question 3

different parts of an app are declaratively defined in a ___ and mediated with user via a ___

Answer 3

yaml file, REST API

Question 4

The high level K8s wrapper for a container is a…

Answer 4

pod, which is the smallest unit of scheduling

Question 5

The wrapper for a pod is a…

Answer 5

deployment

Question 6

In Yaml, everytime you see a section with a ‘API version’ and ‘Kind’, you are defining a…

Answer 6

Kubernetes Object

Question 7

3 networking house rules for K8s

Answer 7

1. all nodes can talk to each other
2. all pods can talk to each other (no NAT)
3. every pod gets its own IP

Question 8

pod ip address is based on

Answer 8

the same one from associated node

Question 9

why do we want to place a service in front of pods?

Answer 9

Because unlike pods, a service’s name and IP address are stable.

Question 10

how does a k8s service’s backend know which pods to connect to?

Answer 10

via the label selector

Question 11

3 main types of K8s services

Answer 11

1. LoadBalander (integrates with public cloud platform)
2. NodePort (cluster wide port, accessible outside cluster)
3. ClusterIP (default, only accessible inside cluster)