Amazon Elastic Load Balancers have the nice feature of being able to do SSL termination, but what does that mean? Usually when using SSL you have to configure each server to have your SSL certificate installed to provide HTTPS. Using Amazon ELB means that you only have to install you SSL certificate in one place and Amazon do everything for you. This also has the benefit of taking load off of your server by taking out the overhead of SSL encryption.

Setting up SSL on Amazon ELB is a bit different from configuring SSL in Apache and is a bit tricky, so I wanted to create a guide on how to do this. This guide is for when using GoDaddy as the SSL provider but this could by any SSL provider using a normal CSR process.

The reason why this is different from a normal CSR process is that Amazon require your keys to be PEM encoded instead of the normal format GoDaddy or other SSL providers generate.

I. Getting a GoDaddy SSL Certificate (Part I)

1. Purchase a GoDaddy Standard SSL Certificate

GoDaddy sells Standard SSL Certificates for anywhere from $12.99/year to $49.99/year.  I highly recommend you do a search for ‘cheap ssl’ on Google and see if there are any advertisements for discounted GoDaddy Standard SSL Certificates.  I was able to buy my certificate for $12.99/year this way.

2. After you complete your purchase, GoDaddy will give you a credit that you can trade for a certificate.  Make the trade and click on ‘Manage Certificate’ next to your new certificate.  This will bring you to a Credits control panel where we will click ‘Request Certificate’ next to your new certificate later on when we are ready to setup your certificate.

II. Creating a Certificate Signing Request (CSR)

Note: To create an SSL certificate, you must first generate and submit a Certificate Signing Request (CSR) to the Certification Authority (CA) (i.e. GoDaddy). The CSR contains your certificate-application information, including your public key. The CSR will also create your public/private key pair used for encrypting and decrypting secure transactions.

These instructions are based on generating the CSR on Ubuntu.

Steps to create a CSR:

1. Make a new directory to hold your project’s SSL-related stuff.  It doesn’t really matter where you put this, but I recommend putting this somewhere safe and should not be in your web directory.

mkdir ssl-cert

2. Move to your newly created folder

cd ssl-cert

3. Use OpenSSL to generate an RSA host key (‘host.key’) using the triple DES encryption, with a 2,048-bit key length (as required by GoDaddy).  Triple DES is just DES times three, but is more secure against brute force attacks because of its longer length.

openssl genrsa -des3 -out host.key 2048

It will ask you for a pass phrase.  This should be a secret password.  Don’t forget the pass phrase you set, as we will need it later.

4. Use OpenSSL to generate a new self-signed certificate (‘host.csr’) using the host key we just created.  This is what you’ll be sending to GoDaddy to model your new SSL after.

openssl req -new -key host.key -out host.csr

You will be prompted with a bunch of questions.  Answer all of them, except the last two ‘extra’ attributes are optional.  Here are example responses:

Country Name (2 letter code) [AU]:UK

State or Province Name (full name) [Some-State]:Warwickshire

Locality Name (eg, city) []:Leamington Spa

Organization Name (eg, company) [Internet Widgits Pty Ltd]:Your Company Name

Organizational Unit Name (eg, section) []:secure.yourdomain.com

Common Name (eg, YOUR name) []:secure.yourdomain.com

Email Address []:contact@yourdomain.com

Please enter the following ‘extra’ attributes

to be sent with your certificate request

A challenge password []:

An optional company name []:

It is very important you don’t mistype anything here, as you can’t change this information without buying a new SSL certificate.  ’Organizational Unit Name’ and ‘Common Name’ must be the hostname you are using for your domain.

III. Getting a GoDaddy’s SSL Certificate (Part II)

1. Return to where we left off with GoDaddy.  You should have clicked ‘Request Certificate’ and see a form where you need to answer the following questions:

Where is your certificate going to be hosted? Third Party

Enter your Certificate Signing Request (CSR) below: [copy the text contents of ‘host.csr’ here]

Select your certificate issuing organization: GoDaddy

Is this certificate for Intel vPro? No

2. Verify everything and then click through to finish.  You should now be able to view and download your GoDaddy SSL certificate from GoDaddy from the ‘Manage Certificates’ section.

IV. Prepare SSL Certificate for Heroku

1. Download your new SSL certificate from GoDaddy’s website into your ‘ssl-cert’ directory that we created in step I.  You will get two files from GoDaddy: ‘secure.yourdomain.com.crt’ and ‘gd_bundle.crt’.  ’secure.yourdomain.com.crt’ is your new SSL certificate.  ’gd_bundle.crt’ contains the SSL issuing certificate chain back to the root SSL certificate.

2. Combine ‘secure.yourdomain.com.crt’ and ‘host.key’:

cat secure.yourdomain.com.crt host.key > host.pem

3. Remove pass phrase from the public key certificate (required by Amazon)

openssl rsa -in host.pem -out nopassphrase.pem

openssl x509 -in host.pem >>nopassphrase.pem

You will be asked for the pass phrase you set in step I.

4. Open ‘nopassphrase.pem’ in a text editor and delete the ‘private key’ section:

—–BEGIN RSA PRIVATE KEY—–

…

—–END RSA PRIVATE KEY—–

5. Combine ‘gd_bundle.crt’ and ‘nopassphrase.pem’:

cat nopassphrase.pem gd_bundle.crt > public.pem

‘gd_bundle.crt’ is a chain file that links your certificate to a original trusted host certificate that GoDaddy owns.

6. Remove pass phrase from the private key certificate (required by Amazon)

openssl rsa -in host.key -out private.key

You will be asked for the pass phrase you set in step I.

You might be asking yourself: What do all of these file extensions mean?  Well, here you go:

*.csr — Certificate Signing Request used for submission to signing authorities that issue SSL certificates

*.crt — Public key of a certificate (same as a *.pem file, but with different extension).  May include a chain of certificates back to the host certificate.  This is what you’ll get from GoDaddy when you download a purchased certificate.

*.pem — Public key of a certificate (same as a *.crt file, but with different extension).  May include a chain of certificates back to the host certificate.  This is what you’ll get from GoDaddy when you download a purchased certificate. 

*.key — Private key of a certificate

V. Configure on Amazon ELB

You are now ok to to take the key files you have just generated and copy and paste them onto your Elastic Load Balancer configuration. When applying SSL you need to create a new ELB. When setting up the load you can make your server config easy by passing the HTTPS traffic from the ELB to port 80 on your server.

Thats it, you now have HTTPS/SSL on your site.