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docs	Amazon AMI Builder (instance-store)

AMI Builder (instance-store)

Type: amazon-instance

The amazon-instance builder is able to create Amazon AMIs backed by instance storage as the root device. For more information on the difference between instance storage and EBS-backed instances, see the "storage for the root device" section in the EC2 documentation.

This builder builds an AMI by launching an EC2 instance from an existing instance-storage backed AMI, provisioning that running machine, and then bundling and creating a new AMI from that machine. This is all done in your own AWS account. The builder will create temporary keypairs, security group rules, etc. that provide it temporary access to the instance while the image is being created. This simplifies configuration quite a bit.

The builder does not manage AMIs. Once it creates an AMI and stores it in your account, it is up to you to use, delete, etc. the AMI.

Configuration Reference

There are many configuration options available for the builder. They are segmented below into two categories: required and optional parameters. Within each category, the available configuration keys are alphabetized.

Required:

access_key (string) - The access key used to communicate with AWS. If not specified, Packer will attempt to read this from environmental variables AWS_ACCESS_KEY_ID or AWS_ACCESS_KEY (in that order).
account_id (string) - Your AWS account ID. This is required for bundling the AMI. This is not the same as the access key. You can find your account ID in the security credentials page of your AWS account.
ami_name (string) - The name of the resulting AMI that will appear when managing AMIs in the AWS console or via APIs. This must be unique. To help make this unique, certain template parameters are available for this value, which are documented below.
instance_type (string) - The EC2 instance type to use while building the AMI, such as "m1.small".
region (string) - The name of the region, such as "us-east-1", in which to launch the EC2 instance to create the AMI.
s3_bucket (string) - The name of the S3 bucket to upload the AMI. This bucket will be created if it doesn't exist.
secret_key (string) - The secret key used to communicate with AWS. If not specified, Packer will attempt to read this from environmental variables AWS_SECRET_ACCESS_KEY or AWS_SECRET_KEY (in that order).
source_ami (string) - The initial AMI used as a base for the newly created machine.
ssh_username (string) - The username to use in order to communicate over SSH to the running machine.
x509_cert_path (string) - The local path to a valid X509 certificate for your AWS account. This is used for bundling the AMI. This X509 certificate must be registered with your account from the security credentials page in the AWS console.
x509_key_path (string) - The local path to the private key for the X509 certificate specified by x509_cert_path. This is used for bundling the AMI.

Optional:

bundle_destination (string) - The directory on the running instance where the bundled AMI will be saved prior to uploading. By default this is "/tmp". This directory must exist and be writable.
bundle_prefix (string) - The prefix for files created from bundling the root volume. By default this is "image-{{.Createtime}}". The CreateTime variable should be used to make sure this is unique, otherwise it can collide with other created AMIs by Packer in your account.
bundle_upload_command (string) - The command to use to upload the bundled volume. See the "custom bundle commands" section below for more information.
bundle_vol_command (string) - The command to use to bundle the volume. See the "custom bundle commands" section below for more information.
iam_instance_profile (string) - The name of an IAM instance profile to launch the EC2 instance with.
security_group_id (string) - The ID (not the name) of the security group to assign to the instance. By default this is not set and Packer will automatically create a new temporary security group to allow SSH access. Note that if this is specified, you must be sure the security group allows access to the ssh_port given below.
ssh_port (int) - The port that SSH will be available on. This defaults to port 22.
ssh_timeout (string) - The time to wait for SSH to become available before timing out. The format of this value is a duration such as "5s" or "5m". The default SSH timeout is "1m", or one minute.
subnet_id (string) - If using VPC, the ID of the subnet, such as "subnet-12345def", where Packer will launch the EC2 instance.
vpc_id (string) - If launching into a VPC subnet, Packer needs the VPC ID in order to create a temporary security group within the VPC.
x509_upload_path (string) - The path on the remote machine where the X509 certificate will be uploaded. This path must already exist and be writable. X509 certificates are uploaded after provisioning is run, so it is perfectly okay to create this directory as part of the provisioning process.

Basic Example

Here is a basic example. It is completely valid except for the access keys:

{
  "type": "amazon-instance",
  "access_key": "YOUR KEY HERE",
  "secret_key": "YOUR SECRET KEY HERE",
  "region": "us-east-1",
  "source_ami": "ami-d9d6a6b0",
  "instance_type": "m1.small",
  "ssh_username": "ubuntu",

  "account_id": "0123-4567-0890",
  "s3_bucket": "packer-images",
  "x509_cert_path": "x509.cert",
  "x509_key_path": "x509.key",
  "x509_upload_path": "/tmp",

  "ami_name": "packer-quick-start {{.CreateTime}}"
}

Note: Packer can also read the access key and secret access key from environmental variables. See the configuration reference in the section above for more information on what environmental variables Packer will look for.

AMI Name Variables

The AMI name specified by the ami_name configuration variable is actually treated as a configuration template. Packer provides a set of variables that it will replace within the AMI name. This helps ensure the AMI name is unique, as AWS requires.

The available variables are shown below:

CreateTime - This will be replaced with the Unix timestamp of when the AMI was built.

Custom Bundle Commands

A lot of the process required for creating an instance-store backed AMI involves commands being run on the actual source instance. Specifically, the ec2-bundle-vol and ec2-upload-bundle commands must be used to bundle the root filesystem and upload it, respectively.

Each of these commands have a lot of available flags. Instead of exposing each possible flag as a template configuration option, the instance-store AMI builder for Packer lets you customize the entire command used to bundle and upload the AMI.

These are configured with bundle_vol_command and bundle_upload_command. Both of these configurations are configuration templates and have support for their own set of template variables.

Bundle Volume Command

The default value for bundle_vol_command is shown below. It is split across multiple lines for convenience of reading. The bundle volume command is responsible for executing ec2-bundle-vol in order to store and image of the root filesystem to use to create the AMI.

sudo -n ec2-bundle-vol \
	-k {{.KeyPath}}  \
	-u {{.AccountId}} \
	-c {{.CertPath}} \
	-r {{.Architecture}} \
	-e {{.PrivatePath}} \
	-d {{.Destination}} \
	-p {{.Prefix}} \
	--batch

The available template variables should be self-explanatory based on the parameters they're used to satisfy the ec2-bundle-vol command.

Bundle Upload Command

The default value for bundle_upload_command is shown below. It is split across multiple lines for convenience of reading. The bundle upload command is responsible for taking the bundled volume and uploading it to S3.

sudo -n ec2-upload-bundle \
	-b {{.BucketName}} \
	-m {{.ManifestPath}} \
	-a {{.AccessKey}} \
	-s {{.SecretKey}} \
	-d {{.BundleDirectory}} \
	--batch \
	--retry

The available template variables should be self-explanatory based on the parameters they're used to satisfy the ec2-upload-bundle command.

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