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