Basics: Servers

Task 1.6

SHH Key Setup on Carolina CloudApps

I want you to first do this from the class computers; they do not need a VPN and Git is already installed. Also, I want you to be familiar with using Git on the class computer in case you are not able to get to class with your laptop.

If, for some reason, you are dealing with an emergency,and you miss this session, or if you are adding this class towards the end of drop add, you can do it from your laptop.

The two following prerequisites will apply in that case:

• If you are off campus, you will need to have installed VPN on your laptop

• you will have had to install Git on your laptop.

Once SSH keys are all set for your computer, it is like having a free pass at the park. You can git push (upload) and git pull (download) anytime, anywhere, without entering a password each time.

We will need to Login to your source control account and open the git bash application to complete this session.

Open https://sc.unc.edu with a browser and login with your Onyen and Onyen password:

1. Accessing SSH Key input screen

See the below image for reference:

1. Click the Avatar image,
2. click settings, click
3. SSH Keys

2. Set up public and private ssh keys on the class computer.

This is what we are working toward seeing on our desktops:

1. Log into the class computer with your Onyen and Onyen password

2. Next, go to the bottom left of the screen where it says "Type here to search" and type in

git bash

1. Launch git bash application when it appears.

2. A terminal will appear showing a command prompt similar to this:

lblakej@DESKTOP-J9MULL MING64 ~ $

Set up the git bash screen on the left side of your screen.

You cannot break the in-class computers: every evening the entire system is wiped and restored.

Therefore...

The class-computer key is transient... it will vanish.

The class computer key that is generated is kind of like the electronic key that you get with a hotel room; its going to get "wiped" when you checkout (logout).

Which is what you want; you don't want someone else logging in and being able to use your key!

That is really not a problem because when you check back in, you can generate a new key and copy it back onto the source control site. So this is what you will have to do if your computer is in the shop for a week or two. It only take a few seconds to set the key up and you can download your files and then upload the changed files before you log out.

Obviously, this can get tedious over the long haul, so you are going to want to be able to set up a key-pair on your own computer—which won't get wiped—unless your hard drive crashes. But if that did happen, and your files were safely at source control, you could generate a new key on your new computer, copy them to the source control, and you would be in business again. If you have two laptops, you can put up two keys at source control. You can work on one or both of these systems and make sure that everything stays in sync.

If you are a bit intimidated by all of this source control lingo, I want to assure you that we are going to just wade into the ocean of git and linux and swim out just a little bit. Out of all of the source control settings, you really just need the ssh panel.

Let's Get Started with some bash commands to set up ssh...

After we finish this on the class computers, you will need to download git and set up ssh keys for you laptop.

PC Users can duplicate this on their laptops exactly as they have done on the class computer after they have downloaded git (which include git bash) for their laptops.

Mac users will also download git, but they will not need, or receive, git bash; they will use the terminal app that is included with Mac OSX. (The quickest way to launch terminal is to hit command + space bar which opens the Spotlight search, and then start typing "terminal").

Once you get the hang of working at the command line, setting up ssh is very quick task; it only requires two commands*:

1. ssh key-gen to make the keys (this will prompt you for two items, but you can just press enter for both)
2. cat ~/.ssh/id_rsa.pub | clip for PC and
   cat ~/.ssh/id_rsa.pub | pbcopy for mac

*The tutorial will have a few more steps: we will move into the .ssh file, list the contents and run the cat command in isolation.

When you click on the tutorial slide show below, it will be added as a new tab in your browser. That way you can have the source control tab and the tutorial tab both in the browser on the right. You do not need the ssh input screen until the very end. After you copy the key in your clipboard, you can click the source control tab.

 Click here: This tutorial is in html format, so it will launch in the browser in a new tab.

I have kept the navigation to a bare minimum so the images can fit in the entire browser window, so click on the image to cycle through the steps. You will go back to the beginning after the last slide. To close the window, just close the tab.