DevOps Classroom Series – 07/Jun/2020

Packer

• Packer is a tool for creating machine images for multiple platforms
• In the case of AWS we call this machine images as AMI and in the case of Azure we call it as VM Image.
• Some of the other machine image formats are
  • VMDK/VMX (Vmware)
  • OVF
  • VHD (HyperV)

Use Cases

• Continuous Delivery: For every release a machine image is created using packer which will be used by terraform to create virtual machines
• Packer is used in Demo Environmets as it consists of machine images

Becoming Effective with Packer

• Understand how to create machine image manually
• Be effective with json format

Basic Packer Terms

• Builder: Builder lets you select the virtual environment (aws, azure, vmware etc) to create machine images
  • Popular Builders are:
    • Amazon EC2
    • Azure
    • Digital Ocean
    • Alicloud ECS
    • Hyper-V
    • Virtual Box
    • VmWare
    • OpenStack
• Provisioner: Are built-in and third-party software to install and configure the machine images. Popular provisioners
  • Ansible
  • Chef
  • Salt
  • puppet
  • Shell
  • Windows Shell

Machine image creation (Manual)

• Lets try to create a machine image for lamp stack.
• For lamp stack steps refer here
• Linux Steps

sudo apt-get update
sudo apt install apache2 -y
sudo apt install php libapache2-mod-php php-mysql php-cli -y
sudo systemctl restart apache2
sudo nano /var/www/html/info.php
sudo systemctl enable apache2
sudo systemctl restart apache2

###
<?php
phpinfo();
?>

http://<publicip>/info.php

How to create a AMI in AWS

• Create a EC2 instance
• Install/Configure your application
• Create image (AMI) from EC2 instance and then use the image (AMI) create for creating further machines
• Delete the Ec2 instance created in step 1 (Optional)

How to create a VM Image in Azure

• Create an Azure VM
• Install/Configure your application
• Create vm image from azure vm and then use the vm create for creating further machines
  • While creating the VM Image, Azure deallocates (Stops) vm and generalize vm (Removing specific user configuration)
• Delete the Azure VM created in step1 as this vm becomes unusable

Installing Packer

• Download Packer from here and add it to the path variable
• If you have choco installed

choco install packer -y

Machine image creation Using Packer

• Refer Here for official docs
• In Packer we create templates Refer Here

AWS AMI Creation

• Lets get started with basic json

{

}

• Now add builders section

{
    "builders": [
        
    ]
}

• Now since we are using aws, lets find aws builders Refer Here

{
    "builders": [
        {
            "type": "amazon-ebs",
            "access_key": "",
            "secret_key": "",
            "region": "us-west-2",
            "ami_name": "mylampv1.0",
            "source_ami": "ami-003634241a8fcdec0",
            "instance_type": "t2.micro",
            "ssh_username": "ubuntu"

        }
    ]
}

• Now we need to install lamp stack, so we will use provisioners. Select Suitable provisioner from here. For this case, i would be using shell provisioner

{
    "builders": [
        {
            "type": "amazon-ebs",
            "access_key": "",
            "secret_key": "",
            "region": "us-west-2",
            "ami_name": "mylampv1.0",
            "source_ami": "ami-003634241a8fcdec0",
            "instance_type": "t2.micro",
            "ssh_username": "ubuntu"

        }
    ],
    "provisioners": [
        {
            "type": "shell",
            "inline": [
                "sudo apt-get update",
                "sudo apt install apache2 -y",
                "sudo apt install php libapache2-mod-php php-mysql php-cli -y",
                "sudo systemctl restart apache2",
                "echo '<?php phpinfo(); ?>'/var/www/html/info.php ",
                "sudo systemctl enable apache2",
                "sudo systemctl restart apache2"

            ]
        }
    ]
}

• Now execute the following commands

packer --help
packer validate --help
packer validate aws.json
packer inspect aws.json

• Now lets create amazon ami by executing packer build aws.json and if you want to execute step by step packer build -debug aws.json
• Now lets add variables refer here

{
    "variables": {
        "aws_secret_key": "",
        "aws_access_key": "",
        "source_ami": "ami-003634241a8fcdec0"
    },
    "builders": [
        {
            "type": "amazon-ebs",
            "access_key": "{{user `aws_access_key`}}",
            "secret_key": "{{user `aws_secret_key`}}",
            "region": "us-west-2",
            "ami_name": "mylamp {{timestamp}}",
            "source_ami": "{{user `source_ami`}}",
            "instance_type": "t2.micro",
            "ssh_username": "ubuntu"

        }
    ],
    "provisioners": [
        {
            "type": "shell",
            "inline": [
                "sudo apt-get update",
                "sudo apt install apache2 -y",
                "sudo apt install php libapache2-mod-php php-mysql php-cli -y",
                "sudo systemctl restart apache2",
                "echo '<?php phpinfo(); ?>'/var/www/html/info.php ",
                "sudo systemctl enable apache2",
                "sudo systemctl restart apache2"

            ]
        }
    ]
}

• Now execute packer packer build -var "aws_secret_key=xxxxx" -var "aws_access_key=xxxx" aws.json
• To the packer script we can add functions Refer Here

Creating VM image in Azure using Packer

• Refer Here for linux images and here for windows images

Exercise:

• Write a Packer template to create nop Commerce image on aws or azure and then use that image in terraform