devopsplayground4-packer

Creating machine and container images for multiple platforms from a single source configuration

Pre-requisites

Installing Packer

• Create a folder named packer in your PC

• Put all the files from folder Template Virtualbox inside the newly created folder in our computer.

• Install packer, you can download and check the instructions from here.

• Download and install Virtualbox from here.

The structure of the packer folder should be the following

Note: The following image represents windows OS

Using Packer

1. Under the command window navigate to the packer folder

• While inside the folder in the command window type:

1. Linux/Mac/Git Bash ./packer

• Windows packer

Make sure the following comes up to know that Packer is working.

   usage: packer [--version] [--help] <command> [<args>]

   Available commands are:
       build       build image(s) from template
       fix         fixes templates from old versions of packer
       inspect     see components of a template
       push        push a template and supporting files to a Packer build service
       validate    check that a template is valid
       version     Prints the Packer version

Working with packer commands

Note: The following commands to call Packer works on windows, please make sure you are using the one that corresponds to your OS

First lets make sure that the template is working properly

Run the following command under the console window

packer validate template.json

The output should be:

Template validated successfully.

Now lets inspect our template

In our command windows lets run:

packer inspect template.json

Packer will show us the structure of our files

Optional variables and their defaults:

  CHECKSUM      = ad4e8c27c561ad8248d5ebc1d36eb172f884057bfeb2c22ead823f59fa8c3dff
  CHECKSUM_TYPE = sha256
  CPUS          = 1
  DISK_SIZE     = 5120
  GUEST_IP      = 10.0.2.15
  GUEST_PORT    = 80
  HOST_IP       = 127.0.0.1
  HOST_PORT     = 8080
  ISO_URL       = debian-8.5.0-amd64-netinst.iso
  MEMORY        = 512
  NAME          = World
  OS_TYPE       = Debian_64
  PASS          = forest
  PROTOCOL      = tcp
  USER          = forest

Builders:

  virtualbox-iso

Provisioners:

  file
  shell
  shell

Note: If your build names contain user variables or template
functions such as 'timestamp', these are processed at build time,
and therefore only show in their raw form here.

Working with user variables

User variables can be defined inside the template in the variables section with the following format:

"variables": {
   "aws_access_key": "",
   "aws_secret_key": ""
 },

This is how we have our variables currently set up in our template.

Packer has two other methods for setting variables

1) From a file

Variables can also be set from an external JSON file. The -var-file flag reads a file.

Note: JSON files can be opened with any text editors.

We are going to create another file called config.json in the packer folder and we are going to put the variable list from our template.json (remember to delete the variables from template.json)

config.json should look like this:

{
  "USER": "forest",
  "PASS": "forest",
  "OS_TYPE": "Debian_64",
  "MEMORY": "512",
  "CPUS": "1",
  "DISK_SIZE": "5120",
  "NAME": "World",
  "PROTOCOL": "tcp",
  "HOST_IP": "127.0.0.1",
  "HOST_PORT": "8080",
  "GUEST_IP": "10.0.2.15",
  "GUEST_PORT": "80",
  "ISO_URL": "debian-8.5.0-amd64-netinst.iso",
  "CHECKSUM": "ad4e8c27c561ad8248d5ebc1d36eb172f884057bfeb2c22ead823f59fa8c3dff",
  "CHECKSUM_TYPE": "sha256"
}

Let's try to validate template.json and see what happens.

Now it is not recognizing the variables. In order to pass them to the template we need to use the -var-file tag.

Packer validate -var-file=config.json template.json

2) From The Command Line

To set variables from the command line, the -var flag is used as a parameter to packer build

Building the template

Finally with all the information given we can build our template by passing the variables located under the config.json file and we are also going to modify one of the values using the -var flag

We want to change the value of the variable that is given under the shell command. The variable being used is NAME. By default it has the value World so we are going to change it to our name.

The command should look like this:

packer build -var-file=config.json -var 'NAME=XXXXX' template.json

Another way to put it would be:
Note: For windows use ^ (caret) instead of \

$ packer build \
    -var-file=config.json \
    -var 'NAME=XXXXX' \
    template.json

After pressing Enter VirtualBox will begin creating the VM and running it in headless mode. Please be careful not to open up a window with the running machine since interaction with it may cause a conflict while generating the image.

Creating an instance from our new image

Once our build has finished we will get the following under our command window:

==> virtualbox-iso: Unregistering and deleting virtual machine...
Build 'virtualbox-iso' finished.

==> Builds finished. The artifacts of successful builds are:
--> virtualbox-iso: VM files in directory: MY_VM_XXXXXXXXXXXXX

Under the folder were we have our template.json a new folder will be created with the name MY_VM_XXXXXXXXXXXXX

Inside this folder you should have now 2 files:

• OVF: This file contains the configuration of our virtual machine.
• VMDK: This file contains our actual virtual machine with the OS

To launch our newly created image we need to open VirtualBox and the go to:

File -> Import (and we look for our new OVF file)

Once the VM has been imported we need to run it.

Taking a look in our new VM

Once our VM is running we can open any browser of choice and type in the URL:

localhost:8080

We should be able to see that apache is working. Afterwards we can type:

localhost:8080/forest.html

This will show the webpage we created with one of our scripts.

PARALLEL BUILDS

Now that we have our template to create a VM under VirtualBox we can use the same configuration to do it under other tools in parallel. Here's an example of the syntax to add VMware to our build.

"builders": [{
    "type": "virtualbox-iso",
    ...
    ...
    "vboxmanage": [
      [ "modifyvm", "{{.Name}}", "--memory", "512" ],
      [ "modifyvm", "{{.Name}}", "--cpus", "1" ]
    ]
  },{
    "type": "vmware-iso",
    ...
    ...
    "vmx_data": {
      "memsize": "512",
      "numvcpus": "1",
    }
  }],

"provisioners": [
  {
    "type": "shell",
    "execute_command": "echo 'password'|sudo -S sh '{{.Path}}'",
    "override": {
      "virtualbox-iso": {
        "scripts": [
          ...
          ...
        ]
      },
      "vmware-iso": {
        "scripts": [
          ...
          ...
        ]
      }
    }
  }
],