etesKubern

Question 1

What is a Pod?

Answer 1

Smallest unit in Kubernetes

Abstraction over container

Question 2

What is Kubernetes?

Answer 2

Open Source Container Orchestration tool

Helps you manage systems that are made up of multiple applications

Question 3

Who developed Kubernetes?

Answer 3

Google

Question 4

Why not just develop our own scripts to do what Kubernetes does?

Answer 4

Difficulty, human error, and some things are not even possible

Question 5

What benefits do Orchestration Tools offer?

Answer 5

High Availability

Scalability

Disaster Recovery

Question 6

What is a node?

Answer 6

x kuber server node?

Sometimes called Worker Nodes

Question 7

How many applications per pod usually?

Answer 7

Usually 1, and maybe some helper containers

Question 8

do pods get their own ip address, or containers?

Answer 8

pods

Question 9

pods are ephemeral

Answer 9

they can die very easily

Question 10

when a pod gets recreated what happens to its ip address?

Answer 10

It gets a new IP

Question 11

What is a Kubernetes Service?

Answer 11

Permanent, static IP address

Question 12

Does each pod get its own service, or each node?

Answer 12

Each pod

Question 13

What is an external service?

Answer 13

public facing

Question 14

what is an internal service?

Answer 14

internal facing, eg, for DBs For communicating between pods

Question 15

What is Ingress component?

Answer 15

A way of providing https and a named domain

route traffic into the cluster

Question 16

What is ConfigMap

Answer 16

external configuration of your application

also if you have to change the url of an DB

Question 17

Should you put credentials into config map

Answer 17

NOOOOO

Question 18

What is Secret?

Answer 18

just like ConfigMap, but used to store secret data, like credentials

bas64 encoded

Question 19

When using volumes in K8, where can they be stored?

Answer 19

on local server

remote, cloud

Question 20

what is a cluster?

Answer 20

xxx

Question 21

Kubernettes replicates nodes

Answer 21

but they will share the same services

Question 22

a service

Answer 22

is also a load balancer

Question 23

what is a deployment?

Answer 23

a blueprint for your myapp pods, you can choose up to how many replicas are allowed too

Question 24

can you replicate DBs using Deployments?

Answer 24

No, because a DB has a state (its data), and when you re-deploy you could have multiple pods all using the same DB, which creates inconsistencies, conflicts, etc

Question 25

What should you use instead of deployment for DBs?

Answer 25

a StatefulSet

Question 26

What is a problem and solution with StatefulSets?

Answer 26

They are hard to get right, so often the DBs will be hosted outside of Kubernetes

Question 27

each node will have multiple pods

Answer 27

yerp

Question 28

What are the three node processes?

Answer 28

Container Runtime Kublet Kube Proxy

Question 29

Kublet services

Answer 29

interacts with both container runtime and the node itself

Question 30

Kublet

Answer 30

Starts the pod

Question 31

Kube Proxy

Answer 31

Forwards the requests between pods in a smart way

Question 32

Master Nodes

Answer 32

x

Question 33

4 Master Node proceses

Answer 33

API Server Scheduler Controller Manager etcd

Question 34

API Server

Answer 34

a cluster gateway acts as a gatekeeper for authentication

Question 35

Scheduler

Answer 35

decides where to put the pod Uses Kublet to actually start Pod

Question 36

Controller Manager

Answer 36

Detects if nodes have died, and reschedule their restart

Question 37

Controller Manager

Answer 37

Detects cluster state changes

Question 38

etcd

Answer 38

a key value store of a cluster state stores info for API Server, Scheduler, and Control Manager

Question 39

What data does etcd NOT store?

Answer 39

Application data

Question 40

Usually is only 1 Master Node used in production?

Answer 40

no, multiple

Question 41

Does a master node or a worker node need more resources?

Answer 41

Worker Nodes