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Using an instance

One uses an instance exactly like one uses any remote Linux server: we ssh to the instance, which connects us to a bash shell running on the instance, which we use just like we do on any Linux machine.

But first, let us see how to "start" ("spin up") and "stop" ("suspend", "spin down") an instance from the EC2 dashboard. We should spin down any instance that we're not going to use for some time (|EG| for a day or more), both for cost reasons (most AWS charges are for instances that are actually running) and to avoid wasting resources---a running instance has to be allocated to an actual physical machine somewhere in the cloud, whereas a stopped machine is merely parked on disk somewhere in the cloud.

.. index:: Spinning up/down an instance

.. index:: Instance; spinning up/down

Spinning up (starting) and spinning down (suspending) an instance

Once you have created your F1 instance, if you click on "Instances" in the left column of your EC2 dashboard, you will see your instance listed in a display similar to the examples shown in :numref:`Fig_AWS_EC2_Instances_Dashboard_B`.

Figs/AWS_EC2_Instances_Dashboard.png

AWS EC2 Instances Dashboard showing one's instances

The figure shows two instances, one called "RSN_AFI_Build2" with instance type "m6i.2xlarge", and the other called "RSN_AFI_Run" with instance type "f1.2xlarge". The latter, because it is an "f1" instance, has an FPGA attached. For each instance, there is a check-box on the the left of the instance name by which one can select/unselect the instance.

When an instance is selected, clicking on the "Instance State" button (near the top) offers a drop-down menu with options including "Start Instance" and "Stop Instance", with the natural meaning of running or suspending your instance. Feel free to stop and start an instance as many times as you like; it's just like taking your laptop in and out of "Suspend" mode. Starting and stopping an instance can take a minute or so; you can refresh your EC2 Instances web page (or click the refresh icon |ICON_REFRESH|) to refresh the Instance state display.

Warning

Don't choose the "Terminate instance" option by accident! That will delete your instance, including any data in its file system. Terminate your instance only when your project is finally finished and, before that, make sure you've copied out any valuable data to your local laptop/desktop or other storage area (see :numref:`Sec_instance_scp` for copying files in/out.

The state of an instance is persistent, |IE| when you re-start an instance, it resumes with the same state where it left off when it was last stopped, with the following exceptions:

  • When an instance is stopped, it loses its network connections. In particular:
  • When an instance is stopped, it loses its FPGA-load, if any (when restarted, it may be allocated to an entirely different physical machine with a different FPGA). On restart you must re-load your AFI into the FPGA.

When you start your instance (select your instance with the check box on the left of the instance name, then menu "Instance state" |RARROW| "Start Instance"), the "Instance state" column will initially inform you that it is starting up and performing some self checks, and finally show it in the "Running" state.

Cost: most AWS charges accrue on instances that are in the "Running" instance state, because they have been allocated to some actual physical machine in the AWS cloud (and with an actual FPGA, if it is an "f1" instance). Charges for "Stopped" instances are comparatively negligible, since they are merely parked on disk somewhere in the cloud. Thus, if you are not using your instance for some time, it is a good idea to place it in the "Stopped" state, and restart it next time you use it.

.. index:: ssh into F1 instance

.. index:: F1 instance; ssh into

Connect to an instance from a local terminal (on your laptop/desktop) using ssh.

In the EC2 instances dashboard (see :numref:`Fig_AWS_Launch_Instance_100_Instances_Running`), select a running instance and click the "Connect" button (near the top of the screen); it will pop up a "Connect to Instance" screen, see :numref:`Fig_AWS_Connect_to_Instance`:

Figs/AWS_Connect_to_Instance.png

"Connect to Instance" screen.

Copy the text of the displayed "Example:", either by cut-and-paste with your mouse or by clicking the clipboard icon at the left.

ssh -i RSN_AWS.pem  ubuntu@ec2-34-227-16-248.compute-1.amazonaws.com

Here, "RSN_AWS.pem" refers to the file containing your private key, which you created earlier (see :numref:`Sec_Create_Key_Pair`), for authenticating logins to your instance.

Important

ssh requires that your file with your private key must have its file permissions set to 0x400 (-r--------), |IE| read-only, and only by owner.

Paste the copied text into a terminal on your local computer (laptop/desktop) to connect to your instance (you may have need to edit the private-key file argument to specify the path to where it is located):

$ ssh -i ~/.ssh/RSN_AWS.pem  ubuntu@ec2-34-227-16-248.compute-1.amazonaws.com

Note: the default userid for an Ubuntu instance created from the standard Ubuntu AMI is ubuntu.

This will open a standard ssh connection to your instance and you will land into an interactive session with the bash shell in Ubuntu on your instance, see :numref:`Fig_AWS_Connect_to_Instance_ssh`:

Figs/AWS_Connect_to_Instance_ssh.png

ssh connection to instance from a terminal on local computer.

You will now be in the familiar bash environment in your instance, and you can interact with it in the normal way. You can explore your home directory on the file system, create and edit files and directories, git clone a repository, use git commands, use the Debian/Ubuntu apt system to install packages, |ETC|

.. index:: scp in and out of F1 instance

.. index:: F1 instance; scp in and out of

Copy files into and out of your instance using scp

In particular, you can use scp to copy files in and out of your instance, as usual:

  • You can use scp from your instance's bash shell to "pull" files from a remote machine.

  • You can use scp from your instance's bash shell to "push" files to a remote machine.

  • You can usse scp from your local machine to "push" files into your instance (note, you need to provide your access key):

    $ scp -i ~/.ssh/RSN_AWS.pem  localfile  centos@ec2-44-203-253-191.compute-1.amazonaws.com:~/

  • You can use scp from your local machine to "pull" files from your instance (note, you need to provide your access key):

    $ scp -i ~/.ssh/RSN_AWS.pem  centos@ec2-44-203-253-191.compute-1.amazonaws.com:~/filename  localfile