# Pre-requirements

- Be comfortable with the UNIX command line

  - navigating directories

  - editing files

  - a little bit of bash-fu (environment variables, loops)

- Some Docker knowledge

  - `docker run`, `docker ps`, `docker build`

  - ideally, you know how to write a Dockerfile and build it
    <br/>
    (even if it's a `FROM` line and a couple of `RUN` commands)

- It's totally OK if you are not a Docker expert!

---

class: extra-details

## Extra details

- This slide should have a little magnifying glass in the top left corner

  (If it doesn't, it's because CSS is hard — Jérôme is only a backend person, alas)

- Slides with that magnifying glass indicate slides providing extra details

- Feel free to skip them if you're in a hurry!

---

class: title

*Tell me and I forget.*
<br/>
*Teach me and I remember.*
<br/>
*Involve me and I learn.*

Misattributed to Benjamin Franklin

[(Probably inspired by Chinese Confucian philosopher Xunzi)](https://www.barrypopik.com/index.php/new_york_city/entry/tell_me_and_i_forget_teach_me_and_i_may_remember_involve_me_and_i_will_lear/)

---

## Hands-on sections

- The whole workshop is hands-on

- We are going to build, ship, and run containers!

- You are invited to reproduce all the demos

- All hands-on sections are clearly identified, like the gray rectangle below

.exercise[

- This is the stuff you're supposed to do!

- Go to [container.training](http://container.training/) to view these slides

- Join the chat room on @@CHAT@@

]

---

class: in-person

## Where are we going to run our containers?

---

class: in-person, pic

![You get five VMs](images/you-get-five-vms.jpg)

---

class: in-person

## You get five VMs

- Each person gets 5 private VMs (not shared with anybody else)

- They'll remain up for the duration of the workshop

- You should have a little card with login+password+IP addresses

- You can automatically SSH from one VM to another

- The nodes have aliases: `node1`, `node2`, etc.

---

class: in-person

## Why don't we run containers locally?

- Installing that stuff can be hard on some machines

  (32 bits CPU or OS... Laptops without administrator access... etc.)

- *"The whole team downloaded all these container images from the WiFi!
  <br/>... and it went great!"* (Literally no-one ever)

- All you need is a computer (or even a phone or tablet!), with:

  - an internet connection

  - a web browser

  - an SSH client

---

class: in-person

## SSH clients

- On Linux, OS X, FreeBSD... you are probably all set

- On Windows, get one of these:

  - [putty](http://www.putty.org/)
  - Microsoft [Win32 OpenSSH](https://github.com/PowerShell/Win32-OpenSSH/wiki/Install-Win32-OpenSSH)
  - [Git BASH](https://git-for-windows.github.io/)
  - [MobaXterm](http://mobaxterm.mobatek.net/)

- On Android, [JuiceSSH](https://juicessh.com/)
  ([Play Store](https://play.google.com/store/apps/details?id=com.sonelli.juicessh))
  works pretty well

- Nice-to-have: [Mosh](https://mosh.org/) instead of SSH, if your internet connection tends to lose packets
  <br/>(available with `(apt|yum|brew) install mosh`; then connect with `mosh user@host`)

---

class: in-person

## Connecting to our lab environment

.exercise[

- Log into the first VM (`node1`) with SSH or MOSH

<!--
```bash
for N in $(seq 1 5); do
  ssh -o StrictHostKeyChecking=no node$N true
done
```

```bash
if which kubectl; then
  kubectl get all -o name | grep -v services/kubernetes | xargs -n1 kubectl delete
fi
```
-->

- Check that you can SSH (without password) to `node2`:
  ```bash
  ssh node2
  ```
- Type `exit` or `^D` to come back to node1

<!-- ```bash exit``` -->

]

If anything goes wrong — ask for help!

---

## Doing or re-doing the workshop on your own?

- Use something like
  [Play-With-Docker](http://play-with-docker.com/) or
  [Play-With-Kubernetes](https://medium.com/@marcosnils/introducing-pwk-play-with-k8s-159fcfeb787b)

  Zero setup effort; but environment are short-lived and
  might have limited resources

- Create your own cluster (local or cloud VMs)

  Small setup effort; small cost; flexible environments

- Create a bunch of clusters for you and your friends
    ([instructions](https://github.com/jpetazzo/container.training/tree/master/prepare-vms))

  Bigger setup effort; ideal for group training

---

## We will (mostly) interact with node1 only

*These remarks apply only when using multiple nodes, of course.*

- Unless instructed, **all commands must be run from the first VM, `node1`**

- We will only checkout/copy the code on `node1`

- During normal operations, we do not need access to the other nodes

- If we had to troubleshoot issues, we would use a combination of:

  - SSH (to access system logs, daemon status...)
  
  - Docker API (to check running containers and container engine status)

---

## Terminals

Once in a while, the instructions will say:
<br/>"Open a new terminal."

There are multiple ways to do this:

- create a new window or tab on your machine, and SSH into the VM;

- use screen or tmux on the VM and open a new window from there.

You are welcome to use the method that you feel the most comfortable with.

---

## Tmux cheatsheet

- Ctrl-b c → creates a new window
- Ctrl-b n → go to next window
- Ctrl-b p → go to previous window
- Ctrl-b " → split window top/bottom
- Ctrl-b % → split window left/right
- Ctrl-b Alt-1 → rearrange windows in columns
- Ctrl-b Alt-2 → rearrange windows in rows
- Ctrl-b arrows → navigate to other windows
- Ctrl-b d → detach session
- tmux attach → reattach to session