182 lines
6.7 KiB
Markdown
182 lines
6.7 KiB
Markdown
---
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description: |
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Packer is able to create Amazon AMIs. To achieve this, Packer comes with
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multiple builders depending on the strategy you want to use to build the AMI.
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layout: docs
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page_title: Amazon AMI Builder
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...
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# Amazon AMI Builder
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Packer is able to create Amazon AMIs. To achieve this, Packer comes with
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multiple builders depending on the strategy you want to use to build the AMI.
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Packer supports the following builders at the moment:
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- [amazon-ebs](/docs/builders/amazon-ebs.html) - Create EBS-backed AMIs by
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launching a source AMI and re-packaging it into a new AMI
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after provisioning. If in doubt, use this builder, which is the easiest to
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get started with.
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- [amazon-instance](/docs/builders/amazon-instance.html) - Create
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instance-store AMIs by launching and provisioning a source instance, then
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rebundling it and uploading it to S3.
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- [amazon-chroot](/docs/builders/amazon-chroot.html) - Create EBS-backed AMIs
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from an existing EC2 instance by mounting the root device and using a
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[Chroot](https://en.wikipedia.org/wiki/Chroot) environment to provision
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that device. This is an **advanced builder and should not be used by
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newcomers**. However, it is also the fastest way to build an EBS-backed AMI
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since no new EC2 instance needs to be launched.
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-> **Don't know which builder to use?** If in doubt, use the [amazon-ebs
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builder](/docs/builders/amazon-ebs.html). It is much easier to use and Amazon
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generally recommends EBS-backed images nowadays.
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# Amazon EBS Volume Builder
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Packer is able to create Amazon EBS Volumes which are preinitialized with a
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filesystem and data.
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- [amazon-ebsvolume](/docs/builders/amazon-ebs-volume.html) - Create EBS volumes
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by launching a source AMI with block devices mapped. Provision the instance,
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then destroy it, retaining the EBS volumes.
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<span id="specifying-amazon-credentials"></span>
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## Specifying Amazon Credentials
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When you use any of the amazon builders, you must provide credentials to the API
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in the form of an access key id and secret. These look like:
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access key id: AKIAIOSFODNN7EXAMPLE
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secret access key: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
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If you use other AWS tools you may already have these configured. If so, packer
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will try to use them, *unless* they are specified in your packer template.
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Credentials are resolved in the following order:
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1. Values hard-coded in the packer template are always authoritative.
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2. *Variables* in the packer template may be resolved from command-line flags
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or from environment variables. Please read about [User
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Variables](https://www.packer.io/docs/templates/user-variables.html)
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for details.
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3. If no credentials are found, packer falls back to automatic lookup.
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### Automatic Lookup
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If no AWS credentials are found in a packer template, we proceed on to the
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following steps:
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1. Lookup via environment variables.
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- First `AWS_ACCESS_KEY_ID`, then `AWS_ACCESS_KEY`
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- First `AWS_SECRET_ACCESS_KEY`, then `AWS_SECRET_KEY`
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2. Look for [local AWS configuration
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files](https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-getting-started.html#cli-config-files)
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- First `~/.aws/credentials`
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- Next based on `AWS_PROFILE`
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3. Lookup an IAM role for the current EC2 instance (if you're running in EC2)
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\~> **Subtle details of automatic lookup may change over time.** The most
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reliable way to specify your configuration is by setting them in template
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variables (directly or indirectly), or by using the `AWS_ACCESS_KEY_ID` and
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`AWS_SECRET_ACCESS_KEY` environment variables.
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Environment variables provide the best portability, allowing you to run your
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packer build on your workstation, in Atlas, or on another build server.
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## Using an IAM Instance Profile
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If AWS keys are not specified in the template, a
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[credentials](https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-getting-started.html#cli-config-files)
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file or through environment variables Packer will use credentials provided by
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the instance's IAM profile, if it has one.
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The following policy document provides the minimal set permissions necessary for
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Packer to work:
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``` {.javascript}
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{
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"Version": "2012-10-17",
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"Statement": [{
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"Effect": "Allow",
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"Action" : [
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"ec2:AttachVolume",
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"ec2:AuthorizeSecurityGroupIngress",
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"ec2:CopyImage",
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"ec2:CreateImage",
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"ec2:CreateKeypair",
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"ec2:CreateSecurityGroup",
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"ec2:CreateSnapshot",
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"ec2:CreateTags",
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"ec2:CreateVolume",
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"ec2:DeleteKeypair",
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"ec2:DeleteSecurityGroup",
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"ec2:DeleteSnapshot",
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"ec2:DeleteVolume",
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"ec2:DeregisterImage",
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"ec2:DescribeImageAttribute",
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"ec2:DescribeImages",
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"ec2:DescribeInstances",
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"ec2:DescribeRegions",
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"ec2:DescribeSecurityGroups",
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"ec2:DescribeSnapshots",
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"ec2:DescribeSubnets",
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"ec2:DescribeTags",
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"ec2:DescribeVolumes",
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"ec2:DetachVolume",
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"ec2:GetPasswordData",
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"ec2:ModifyImageAttribute",
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"ec2:ModifyInstanceAttribute",
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"ec2:ModifySnapshotAttribute",
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"ec2:RegisterImage",
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"ec2:RunInstances",
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"ec2:StopInstances",
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"ec2:TerminateInstances"
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],
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"Resource" : "*"
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}]
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}
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```
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## Troubleshooting
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### Attaching IAM Policies to Roles
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IAM policies can be associated with user or roles. If you use packer with IAM
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roles, you may encounter an error like this one:
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==> amazon-ebs: Error launching source instance: You are not authorized to perform this operation.
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You can read more about why this happens on the [Amazon Security
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Blog](https://blogs.aws.amazon.com/security/post/Tx3M0IFB5XBOCQX/Granting-Permission-to-Launch-EC2-Instances-with-IAM-Roles-PassRole-Permission).
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The example policy below may help packer work with IAM roles. Note that this
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example provides more than the minimal set of permissions needed for packer to
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work, but specifics will depend on your use-case.
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``` {.json}
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{
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"Sid": "PackerIAMPassRole",
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"Effect": "Allow",
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"Action": "iam:PassRole",
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"Resource": [
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"*"
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]
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}
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```
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### Checking that system time is current
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Amazon uses the current time as part of the [request signing
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process](http://docs.aws.amazon.com/general/latest/gr/sigv4_signing.html). If
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your system clock is too skewed from the current time, your requests might
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fail. If that's the case, you might see an error like this:
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==> amazon-ebs: Error querying AMI: AuthFailure: AWS was not able to validate the provided access credentials
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If you suspect your system's date is wrong, you can compare it against
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http://www.time.gov/. On Linux/OS X, you can run the `date` command to get the
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current time. If you're on Linux, you can try setting the time with ntp by
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running `sudo ntpd -q`.
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