Rails%203%20In%20Action

392 CHAPTER 14 Deployment
To be as hard to guess as a normal SSH key, a password would have to contain 634
random letters and numbers.
—OpenSSH Configuring
Not many people today would be willing to use a password containing 634 random letters
and numbers! Considering the average password length is 8 characters, this a vast
improvement over password-based authentication.
You’re going to enable this key-based authentication for both your current user
and your ticketeeapp.com. For now, use the same key generated for use with GitHub;
however, it’s recommended that a different key be used for the server.
Public keys are stored at a file called .ssh/authorized_keys located in the user’s
home directory, the user being the user you will connect as through SSH. When the
user attempts to connect to the server, the private and public keys are used to confirm
the user’s identity. 17 Because the chances against two users having the same public and
private key are so astronomically high, it is generally accepted as a secure means of
authentication.
In this instance, you’ll create two of these ~/.ssh/authorized_keys files: one for each
user. In each case, create the ~/.ssh directory before creating authorized_keys. Begin
with the user you’re currently logged in as.
Let’s create the ~/.ssh directory now using this command:
mkdir ~/.ssh
Now you need to copy over the public key from your local computer to the ~/.ssh directory
on the server, which you can do by running this command on your local system:
# NOTE: Run this on your *local* machine, not the server!
scp ~/.ssh/id_rsa.pub user@your-server:~/.ssh/[your_name]_key.pub
If you’re using Vagrant…
Vagrant already has a ~/.ssh/authorized_keys file, so there’s no need to re-create
it. Overwriting this file may cause vagrant ssh to no longer work.
You will also need to forward the SSH port from the virtual machine launched by
Vagrant to a local port in order to connect without using Vagrant. While you’re here,
forward the HTTP port (80) as well so that you can access it from the outside. Go into
the Ubuntu directory that you created at the beginning of this chapter, open Vagrant-
File, and add this inside the Vagrant::Config.run block:
config.vm.forward_port "ssh", 22, 2200
config.vm.forward_port "http", 80, 4567
To connect to this server, use port 2200 for SSH and port 4567 for HTTP. When you
use the scp command, the port can be specified using the -P (capital p) option and
ssh using -p (lowercase p), with the port number specified directly after this option.
In places where these commands are used, substitute your-server with localhost
and user with vagrant.
17 For a good explanation of how this process works, check this page: http://unixwiz.net/techtips/ssh-agentforwarding.html#agent.