Logging onto Cloud

Overview

Teaching: 5 min
Exercises: 5 min

Questions

• How do I connect to a cloud instance?

Objectives

• Log onto to a running instance

• Log off from a running instance

Important Note

This lesson covers how to log into, and out of, an already running cloud instance.

Background to cloud computing

To access the pre-configured workshop data, you’ll need to use our log-in credentials (user name and password). A user name will be assigned to you at the workshop. In the following, always replace login with your user name and the password with the password assigned to you.

Log-in Credentials (case-sensitive!)

• Username: login
• Password: password

But first, you need a place to log into! To find the instance that’s attached to that data, you’ll need something called an IP address. Your instructor should have given this to you at the beginning of the workshop.

An IP address is essentially the numerical version of a web address like www.amazon.com

Recall that cloud computing is about choice. You can rent just a single processor on a large computer for a small project, or you can rent hundreds of processors spread across multiple computers for a large project. In either case, once you rent the collection of processors, the cloud provider will present your rental to you as if it was a single computer. So, the physical computers that host your instances don’t really move, but every time you launch a new instance, it will have a new IP address.

So, each time you launch a new instance, the IP address changes, but your Log-in Credentials don’t have to.

Connection Protocols

We will use a protocol called Secure Shell (SSH) that, as the name implies, provides you with a secure way to use a shell. In our case, the shell will be running on a remote machine. This protocol is available for every operating system, but sometimes requires additional software.

Logging onto a cloud instance

Please select the platform you wish to use for the exercises: AWS_UNIX AWS_Windows

$ ssh login@ip_address

The authenticity of host 'ec2-52-91-14-206.compute-1.amazonaws.com (52.91.14.206)' can't be established.
ECDSA key fingerprint is SHA256:S2mMV8mCThjJHm0sUmK2iOE5DBqs8HiJr6pL3x/XxkI.
Are you sure you want to continue connecting (yes/no)?

Logging off a cloud instance

Logging off your instance is a lot like logging out of your local computer: it stops any processes that are currently running, but doesn’t shut the computer off. AWS instances acrue charges whenever they are running, even if you are logged off.

If you are completely done with your AWS instance, you will need to terminate it after you log off. Instructions for terminating an instance are here: launching cloud instances on your own.

To log off, use the exit command in the same terminal you connected with. This will close the connection, and your terminal will go back to showing your local computer:

login@ip-172-31-62-209 $ exit

Amandas-MacBook-Pro-3 $

Logging back in

Internet connections can be slow or unstable. If you’re just browsing the internet, that means you have reload pages, or wait for pictures to load. When you’re working in cloud, that means you’ll sometimes be suddenly disconnected from your instance when you weren’t expecting it. Even on the best internet connections, your signal will occasionally drop, so it’s good to know the above SSH steps, and be able to log into AWS without looking up the instructions each time.

In the next section, we’ll also show you some programs that you can use to keep your processes going even if your connection drops. But for now, just practice logging on and off a few times.

Key Points

• You can use one set of log-in credentials for many instances

• Logging off an instance is not the same as turning off an instance