177 lines
7.6 KiB
Markdown
177 lines
7.6 KiB
Markdown
---
|
|
layout: "intro"
|
|
page_title: "Build an Image"
|
|
prev_url: "/intro/getting-started/setup.html"
|
|
next_url: "/intro/getting-started/provision.html"
|
|
next_title: "Provision"
|
|
---
|
|
|
|
# Build an Image
|
|
|
|
With Packer installed, let's just dive right into it and build our first
|
|
image. Our first image will be an [Amazon EC2 AMI](http://aws.amazon.com/ec2/)
|
|
with Redis pre-installed. This is just an example. Packer can create images
|
|
for [many platforms](/intro/platforms.html) with anything pre-installed.
|
|
|
|
If you don't have an AWS account, [create one now](http://aws.amazon.com/free/).
|
|
For the example, we'll use a "t1.micro" instance to build our image, which
|
|
qualifies under the AWS [free-tier](http://aws.amazon.com/free/), meaning
|
|
it will be free. If you already have an AWS account, you may be charged some
|
|
amount of money, but it shouldn't be more than a few cents.
|
|
|
|
<div class="alert alert-block alert-warn">
|
|
<strong>Note</strong> that if you're not using an account that qualifies under
|
|
the AWS <a href="http://aws.amazon.com/free/">free-tier</a>, you may be
|
|
charged to run these examples. The charge should only be a few cents, but
|
|
we're not responsible if it ends up being more.
|
|
</div>
|
|
|
|
Packer can build images for [many platforms](/intro/platforms.html) other than
|
|
AWS, but AWS requires no additional software installed on your computer and
|
|
their [free-tier](http://aws.amazon.com/free/) makes it free to use for most
|
|
people. This is why we chose to use AWS for the example. If you're uncomfortable
|
|
setting up an AWS account, feel free to follow along as the basic principles
|
|
apply to the other platforms as well.
|
|
|
|
## The Template
|
|
|
|
The configuration file used to define what image we want built and how
|
|
is called a _template_ in Packer terminology. The format of a template
|
|
is simple [JSON](http://www.json.org/). JSON struck the best balance between
|
|
human-editable and machine-editable, allowing both hand-made templates as well
|
|
as machine generated templates to easily be made.
|
|
|
|
We'll start by creating the entire template, then we'll go over each section
|
|
briefly. Create a file `example.json` and fill it with the following contents:
|
|
|
|
<pre class="prettyprint">
|
|
{
|
|
"variables": {
|
|
"aws_access_key": "",
|
|
"aws_secret_key": ""
|
|
},
|
|
"builders": [{
|
|
"type": "amazon-ebs",
|
|
"access_key": "{{user `aws_access_key`}}",
|
|
"secret_key": "{{user `aws_secret_key`}}",
|
|
"region": "us-east-1",
|
|
"source_ami": "ami-de0d9eb7",
|
|
"instance_type": "t1.micro",
|
|
"ssh_username": "ubuntu",
|
|
"ami_name": "packer-example {{timestamp}}"
|
|
}]
|
|
}
|
|
</pre>
|
|
|
|
When building, you'll pass in the `aws_access_key` and `aws_access_key` as
|
|
a [user variable](/docs/templates/user-variables.html), keeping your secret
|
|
keys out of the template. You can create security credentials
|
|
on [this page](https://console.aws.amazon.com/iam/home?#security_credential).
|
|
An example IAM policy document can be found in the [Amazon EC2 builder docs](/docs/builders/amazon.html).
|
|
|
|
This is a basic template that is ready-to-go. It should be immediately recognizable
|
|
as a normal, basic JSON object. Within the object, the `builders` section
|
|
contains an array of JSON objects configuring a specific _builder_. A
|
|
builder is a component of Packer that is responsible for creating a machine
|
|
and turning that machine into an image.
|
|
|
|
In this case, we're only configuring a single builder of type `amazon-ebs`.
|
|
This is the Amazon EC2 AMI builder that ships with Packer. This builder
|
|
builds an EBS-backed AMI by launching a source AMI, provisioning on top of
|
|
that, and re-packaging it into a new AMI.
|
|
|
|
The additional keys within the object are configuration for this builder, specifying things
|
|
such as access keys, the source AMI to build from, and more.
|
|
The exact set of configuration variables available for a builder are
|
|
specific to each builder and can be found within the [documentation](/docs).
|
|
|
|
Before we take this template and build an image from it, let's validate the template
|
|
by running `packer validate example.json`. This command checks the syntax
|
|
as well as the configuration values to verify they look valid. The output should
|
|
look similar to below, because the template should be valid. If there are
|
|
any errors, this command will tell you.
|
|
|
|
```
|
|
$ packer validate example.json
|
|
Template validated successfully.
|
|
```
|
|
|
|
Next, let's build the image from this template.
|
|
|
|
An astute reader may notice that we said earlier we'd be building an
|
|
image with Redis pre-installed, and yet the template we made doesn't reference
|
|
Redis anywhere. In fact, this part of the documentation will only cover making
|
|
a first basic, non-provisioned image. The next section on provisioning will
|
|
cover installing Redis.
|
|
|
|
## Your First Image
|
|
|
|
With a properly validated template. It is time to build your first image.
|
|
This is done by calling `packer build` with the template file. The output
|
|
should look similar to below. Note that this process typically takes a
|
|
few minutes.
|
|
|
|
```
|
|
$ packer build \
|
|
-var 'aws_access_key=YOUR ACCESS KEY' \
|
|
-var 'aws_secret_key=YOUR SECRET KEY' \
|
|
example.json
|
|
==> amazon-ebs: amazon-ebs output will be in this color.
|
|
|
|
==> amazon-ebs: Creating temporary keypair for this instance...
|
|
==> amazon-ebs: Creating temporary security group for this instance...
|
|
==> amazon-ebs: Authorizing SSH access on the temporary security group...
|
|
==> amazon-ebs: Launching a source AWS instance...
|
|
==> amazon-ebs: Waiting for instance to become ready...
|
|
==> amazon-ebs: Connecting to the instance via SSH...
|
|
==> amazon-ebs: Stopping the source instance...
|
|
==> amazon-ebs: Waiting for the instance to stop...
|
|
==> amazon-ebs: Creating the AMI: packer-example 1371856345
|
|
==> amazon-ebs: AMI: ami-19601070
|
|
==> amazon-ebs: Waiting for AMI to become ready...
|
|
==> amazon-ebs: Terminating the source AWS instance...
|
|
==> amazon-ebs: Deleting temporary security group...
|
|
==> amazon-ebs: Deleting temporary keypair...
|
|
==> amazon-ebs: Build finished.
|
|
|
|
==> Builds finished. The artifacts of successful builds are:
|
|
--> amazon-ebs: AMIs were created:
|
|
|
|
us-east-1: ami-19601070
|
|
```
|
|
|
|
At the end of running `packer build`, Packer outputs the _artifacts_
|
|
that were created as part of the build. Artifacts are the results of a
|
|
build, and typically represent an ID (such as in the case of an AMI) or
|
|
a set of files (such as for a VMware virtual machine). In this example,
|
|
we only have a single artifact: the AMI in us-east-1 that was created.
|
|
|
|
This AMI is ready to use. If you wanted you can go and launch this AMI
|
|
right now and it would work great.
|
|
|
|
<div class="alert alert-block alert-info">
|
|
<strong>Note:</strong> Your AMI ID will surely be different than the
|
|
one above. If you try to launch the one in the example output above, you
|
|
will get an error. If you want to try to launch your AMI, get the ID from
|
|
the Packer output.
|
|
</div>
|
|
|
|
## Managing the Image
|
|
|
|
Packer only builds images. It does not attempt to manage them in any way.
|
|
After they're built, it is up to you to launch or destroy them as you see
|
|
fit. As a result of this, after running the above example, your AWS account
|
|
now has an AMI associated with it.
|
|
|
|
AMIs are stored in S3 by Amazon, so unless you want to be charged about $0.01
|
|
per month, you'll probably want to remove it. Remove the AMI by
|
|
first deregistering it on the [AWS AMI management page](https://console.aws.amazon.com/ec2/home?region=us-east-1#s=Images).
|
|
Next, delete the associated snapshot on the
|
|
[AWS snapshot management page](https://console.aws.amazon.com/ec2/home?region=us-east-1#s=Snapshots).
|
|
|
|
Congratulations! You've just built your first image with Packer. Although
|
|
the image was pretty useless in this case (nothing was changed about it),
|
|
this page should've given you a general idea of how Packer works, what
|
|
templates are, and how to validate and build templates into machine
|
|
images.
|