Omar Abdel-Wahab

A friendly geek, a serial entrepreneur and a veteran hacker.
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Deploying Rails using AWS CodeDeploy

29 Nov 2015

Assumptions

The following tutorial uses: us-east-1, Ubuntu 14.04, Rbenv, Foreman

IAM

We will create a new role that we will be launching our EC2 with. EC2 instances launched with the new role will be able to:

  1. Download and install CodeDeploy Agent from S3.
  2. Grant CodeDeploy access to our EC2 instances.

Create IAM Role

  1. Create a new role, give it a name.
  2. Attach Policy:
  3. AWSCodeDeployRole
  4. AmazonS3ReadOnlyAccess
  5. CodeDeployEC2Permissions
  6. Edit trust relationship:

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     {
       "Version": "2012-10-17",
       "Statement": [
         {
           "Sid": "",
           "Effect": "Allow",
           "Principal": {
             "Service": "codedeploy.amazonaws.com"
           },
           "Action": "sts:AssumeRole"
         },
         {
           "Sid": "",
           "Effect": "Allow",
           "Principal": {
             "Service": "ec2.amazonaws.com"
           },
           "Action": "sts:AssumeRole"
         }
       ]
     }
    

VPC

Create a new VPC

I prefer setting up a separate VPC for every application, feel free to ignore this step if you don’t really care about this. Class B private IPs provide a decent number of hosts and that’s what I’ll use here.

  1. Create a new VPC
  2. Use CIDR 172.16.0.0/16
  3. Leave Tenancy as default unless you know what you’re doing.

Subnets

Using multiple subnets will allow Scalability Groups to utilize multiple availability zones improves redundancy.

  1. Create a new subnet for availability zone.
  2. For the CIDR, use 172.16.X.0/24, this would give you 251 IPs per subnet.
  3. Repeat for each availability zone or to your liking.

Internet Gateway

  1. Create a new Internet Gateway to allow your VPC to receive traffic from the Internet.
  2. Choose the gateway and attach it to your VPC.

Route Table

For Internet requests to reach your gateway, you need a routing table.

  1. Create a routing table or use the one created alongside the VPC
  2. Go to: Routes > Edit > Add another route
  3. Set Destination as: 0.0.0.0/0
  4. Target should be have one autocomplete option: the gateway you created above.
  5. Save.

Security Group

To make things more tidy, we will create a per-VPC security group and we will attach it to all resources we create. This would allow globally enabling certain ports or block certain IPs from accessing all resources.

AMI

We now need to create an AMI that has all our project’s OS dependencies installed. If you already have an AMI, skip to “Install CodeDeploy Agent”

We will use a setup similar to Heroku’s handling of Procfile by using a single AMI that can dynamically be assigned one of the processes defined in the

1
Procfile
.

Launch a new instance

Launch a new EC2 Instance and make sure you have AMI Role set to:

1
CodeDeployProfile
.

Install Ruby and Bundler

Install Rbenv and your chosen Ruby version:

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sudo apt-get update
sudo apt-get install git-core curl zlib1g-dev build-essential libssl-dev libreadline-dev libyaml-dev libsqlite3-dev sqlite3 libxml2-dev libxslt1-dev libcurl4-openssl-dev python-software-properties libffi-dev
cd
git clone git://github.com/sstephenson/rbenv.git .rbenv
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(rbenv init -)"' >> ~/.bashrc
exec $SHELL
git clone git://github.com/sstephenson/ruby-build.git ~/.rbenv/plugins/ruby-build
echo 'export PATH="$HOME/.rbenv/plugins/ruby-build/bin:$PATH"' >> ~/.bashrc
exec $SHELL
git clone https://github.com/sstephenson/rbenv-gem-rehash.git ~/.rbenv/plugins/rbenv-gem-rehash
rbenv install 2.2.3
rbenv global 2.2.3
ruby -v

Reference: GoRails

Install CodeDeploy Agent

To install the agent, run the following commands:

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ssh -i {PEM_FILE_PATH} ubuntu@INSTANCE_IP_OR_DNS_NAME
sudo apt-get update
sudo apt-get install awscli
sudo apt-get install ruby2.0
cd /home/ubuntu
# Replace us-east-1 with your VPC region.
sudo aws s3 cp s3://aws-codedeploy-us-east-1/latest/install . --region us-east-1
sudo chmod +x ./install
sudo ./install auto

If you get an error on

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aws s3
command, then you either didn’t launch the EC2 instance with the role we created in IAM section or you didn’t follow the steps correctly.

Reference: AWS CodeDeploy

Create Upstart script

We need to have our application process start automatically on machine start. In order to get this to work, we will be using Ubuntu’s Upstart.

The following script uses

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Foreman
to run the correspondant process defined in the
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Procfile
. Make sure you install
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Foreman
gem by running the command:

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gem install foreman

Then, proceed to creating the Upstart script.

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sudo cat > /etc/init/app.conf << EOS
respawn
start on (local-filesystems and net-device-up IFACE!=lo)
stop on [!12345]
setuid ubuntu
script
set -e
chdir /app/current
export PATH=/home/ubuntu/.rbenv/bin:/home/ubuntu/.rbenv/shims:$PATH
export RAILS_ENV=production
export PORT=3000
export PROCESS=$(cat /app/role)
echo " * Starting process: $PROCESS..."
foreman start $PROCESS
end script
EOS

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