Add SSH config tutorial

doc/source/chapter02_beginner-tutorial/quick-start.rst

@@ -192,4 +192,4 @@ There are two different ways to stop being charged:
   Unless you save your system as an AMI or transfer the data to other storage services, 
   you will lose all your data and software.
 
-You will learn how to save your data and configurations persistently in the next tutorials.
+You will learn how to save your data and configurations persistently in the next tutorials. You might also want to :doc:`simplify your ssh login command <../chapter06_appendix/ssh-config>`.

doc/source/chapter06_appendix/index.rst

@@ -7,6 +7,7 @@ This chapter provides additional resources that don't fit into the main tutorial
    :maxdepth: 2
 
    aws-resources-for-gc
+   ssh-config
    keep-running
    sample-python-code
    plot_NASANEX

doc/source/chapter06_appendix/ssh-config.rst

@@ -0,0 +1,66 @@
+Simplify SSH login with config file
+===================================
+
+In the :ref:`quick start guide <quick-start-label>` you used a lengthy command ``ssh -i "xx.pem" ubuntu@xxx.com`` to login. To copy files by ``scp``, the command would be even longer::
+  
+  scp -i "xx.pem" local_file ubuntu@xxx.com:~/ 
+  
+Fortunately, those commands can be simplified to ``ssh ec2`` and ``scp local_file ec2:~/``, skipping the Key Pair argument ``-i "xx.pem"`` and even the EC2 address.
+
+Set up SSH config file
+^^^^^^^^^^^^^^^^^^^^^^
+
+For example, say the full ssh command is::
+
+  ssh -i "~/.ssh/my-aws-key.pem" ubuntu@ec2-35-169-93-188.compute-1.amazonaws.com
+
+Just open the file ``~/.ssh/config`` (create it if doesn't exist), and enter the following content. Then you will be able to use the shortcuts. ::
+
+  Host ec2
+    Hostname ec2-35-169-93-188.compute-1.amazonaws.com
+    user ubuntu
+    IdentityFile ~/.ssh/my-aws-key.pem
+    Port 22
+
+"Host" is the shortcut you want to use in ``ssh`` and ``scp`` commands. "user", "IdentityFile" (EC2 Key Pair), and "Port" (always 22 for ``ssh``) are almost never changed for different EC2 instances. So you only need to change "Hostname" everytime you have a new instance.
+
+Enable port forwarding
+^^^^^^^^^^^^^^^^^^^^^^
+
+Port forwarding for Jupyter can be done usual::
+  
+  ssh ec2 -L 8999:localhost:8999
+
+Or can be also included in the config file::
+  
+  Host ec2
+    Hostname ec2-35-169-93-188.compute-1.amazonaws.com
+    user ubuntu
+    IdentityFile ~/.ssh/my-aws-key.pem
+    Port 22
+    LocalForward 8999 localhost:8999
+
+For multiple servers
+^^^^^^^^^^^^^^^^^^^^
+
+You can add multiple entries for multiple EC2 instances. Say you've launched a bigger instance in addition to the existing one::
+
+  Host ec2
+    Hostname ec2-35-169-93-188.compute-1.amazonaws.com
+    user ubuntu
+    IdentityFile ~/.ssh/my-aws-key.pem
+    Port 22
+  Host ec2-big
+    Hostname xxxxx.com
+    user ubuntu
+    IdentityFile ~/.ssh/my-aws-key.pem
+    Port 22
+
+Additional notes
+^^^^^^^^^^^^^^^^
+
+1. Note that if you stop and then re-start an EC2 instance, its address will change. The address can be fixed by `AWS Elastic IP <https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/elastic-ip-addresses-eip.html>`_, but I find that modifying "Hostname" in ``~/.ssh/config`` is generally quicker.
+
+2. Our tutorial AMI is based on Ubuntu, thus the user name. Other operating systems would have `different user names <https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/TroubleshootingInstancesConnecting.html#TroubleshootingInstancesConnectingMindTerm>`_.
+
+3. There are similar tutorials for SSH Config `online <http://fuzzyblog.io/blog/aws/2016/09/20/aws-tutorial-08-using-ssh-s-config-file-with-your-aws-boxes.html>`_.