using-docker-kubernetes.RMd

---
title: "Intro to Docker and Kubernetes"
author: 'Kim Fitter '
date: "8 July 2020"
output:
  xaringan::moon_reader: default
  html_document: default
---

```{r setup, include=FALSE}
options(htmltools.dir.version = TRUE)
knitr::opts_chunk$set(
	echo = FALSE,
	message = FALSE,
	warning=FALSE
)
```

```{r load packages}
library(xaringan)
```


class: inverse, center, middle

<center> <img src="https://pbs.twimg.com/media/EbSaQLpXgAAaJY8?format=jpg&name=medium" height="500"> </center>


---


## What are Containers ?

- Packaged code, dependencies and and config
- Share operating systems
- Predictable
- Repeatable 
- Immutable
- Solves the “but it works on my machine” problem


<center>
<span>
 
 <img src="https://www.docker.com/sites/default/files/d8/2018-11/container-vm-whatcontainer_2.png"  height="250" >  <img src="https://www.docker.com/sites/default/files/d8/2018-11/docker-containerized-appliction-blue-border_2.png"  height="250" >
</span></center>

---
## What is Docker?

Docker by Docker Inc automates the development, testing and  deployment of applications inside software containers.

- Docker engine is the layer on which Docker runs.

- The Docker Client is the UI 

- The Dockerfile is just a text file list of steps to build the image to get the container 




---

## Docker Images

A Docker **image** is a pre-built environment for a certain technology or service.

For example official Node.js image is available at the [Docker Hub]( https://hub.docker.com/_/node/).

<center> <img src="https://docs.microsoft.com/en-us/dotnet/architecture/microservices/container-docker-introduction/media/docker-containers-images-registries/taxonomy-of-docker-terms-and-concepts.png" height="350"> </center>

---

## How to Run a Node.js app using Docker

Create app and a <a href="https://medium.com/faun/how-to-build-a-node-js-application-with-docker-f596fbd3a51">Dockerfile</a>  :

<code>
FROM node:12-alpine

RUN mkdir -p /home/node/app/node_modules && chown -R node:node /home/node/app

WORKDIR /home/node/app

COPY package*.json ./

USER node

RUN npm install

COPY --chown=node:node . .

EXPOSE 3000

CMD [ "node", "app.js" ]
</code>

Then build image and run container, and view your app in `http://localhost:3000`


---

class: inverse

## What is Kubernetes

Kubernetes is also known as **K8S**.

The abbreviation **K8s** is derived by replacing the eight letters of “ubernete” with the digit 8.

The Kubernetes Project was **open-sourced** by Google in 2014



<center> <img src="https://pbs.twimg.com/media/EaBLxWGWkAMkqnB?format=jpg&name=small" width ="300"> </center>

---

class: inverse

## What does Kubernetes do?

Kubernetes is a container management platform that orchestrates container workloads.

- A cluster is a set of nodes (physical machines) virtually connected with each other and run containerised applications. 
-  A master node manages the cluster and schedules the containers to run on the cluster’s nodes.
- A pod within a node contains one or more containers
- Specify configuration with YAML (Yet Another Markup Language) 

<center> <img src="https://miro.medium.com/max/1400/1*opw2Ethwo-ebWtqijq8ZBQ.png" width="350"> </center>




---
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## When to use Kubernetes?

- Kubernetes can be an overkill for simple applications
- Complex with steep learning curve
- Short term decrease in productivity to achieve consistency
- Need to hire K8s expertise
- Powerful at scale


<center> <img src="https://pbs.twimg.com/media/EPETtt-WsAYPWRI?format=jpg&name=small" width="300"> </center>





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# Thanks!

Slides created with the `xaringan` R package



### Link to materials

https://github.com/kimnewzealand/R-tutorials