Lucas Bajolet
ec1d2e68f5
Fingerprints are how we link a packer build to an iteration on HCP. These are computed automatically from the Git SHA in the current state, and are unique to the bucket/iteration. The main problem with this approach is that while sound in theory, it quickly falls apart when users want to run the same build configuration twice, but expect a new image to be created. With the current model, this fails, as the iteration with the current SHA already exists. While this is solvable through environment variables, or by committing a change to the repository, we think this is not clear enough, and causes an extra step to what should otherwise be a simple process. Therefore, to lower the barrier of entry into HCP, we change this behaviour with this commit. Now, fingerprints are randomly generated ULIDs instead of a git SHA, and a new one is always generated, unless one is already specified in the environment. This makes continuation of an existing iteration a conscious choice rather than something automatic, and virtually eliminates conflicts such as the ones described above.
Packer
Packer is a tool for building identical machine images for multiple platforms from a single source configuration.
Packer is lightweight, runs on every major operating system, and is highly performant, creating machine images for multiple platforms in parallel. Packer comes out of the box with support for many platforms, the full list of which can be found at https://www.packer.io/docs/builders.
Support for other platforms can be added via plugins.
The images that Packer creates can easily be turned into Vagrant boxes.
Quick Start
Note: There is a great introduction and getting started guide for those with a bit more patience. Otherwise, the quick start below will get you up and running quickly, at the sacrifice of not explaining some key points.
First, download a pre-built Packer binary for your operating system or compile Packer yourself.
After Packer is installed, create your first template, which tells Packer what platforms to build images for and how you want to build them. In our case, we'll create a simple AMI that has Redis pre-installed.
Save this file as quick-start.pkr.hcl. Export your AWS credentials as the
AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables.
variable "access_key" {
type = string
default = "${env("AWS_ACCESS_KEY_ID")}"
}
variable "secret_key" {
type = string
default = "${env("AWS_SECRET_ACCESS_KEY")}"
sensitive = true
}
locals { timestamp = regex_replace(timestamp(), "[- TZ:]", "") }
source "amazon-ebs" "quick-start" {
access_key = "${var.access_key}"
ami_name = "packer-example ${local.timestamp}"
instance_type = "t2.micro"
region = "us-east-1"
secret_key = "${var.secret_key}"
source_ami = "ami-af22d9b9"
ssh_username = "ubuntu"
}
build {
sources = ["source.amazon-ebs.quick-start"]
}
Next, tell Packer to build the image:
$ packer build quick-start.pkr.hcl
...
Packer will build an AMI according to the "quick-start" template. The AMI will be available in your AWS account. To delete the AMI, you must manually delete it using the AWS console. Packer builds your images, it does not manage their lifecycle. Where they go, how they're run, etc., is up to you.
Documentation
Comprehensive documentation is viewable on the Packer website at https://www.packer.io/docs.
Contributing to Packer
See CONTRIBUTING.md for best practices and instructions on setting up your development environment to work on Packer.
Unmaintained Plugins
As contributors' circumstances change, development on a community maintained plugin can slow. When this happens, HashiCorp may use GitHub's option to archive the plugin’s repository, to clearly signal the plugin's status to users.
What does unmaintained mean?
- The code repository and all commit history will still be available.
- Documentation will remain on the Packer website.
- Issues and pull requests are monitored as a best effort.
- No active development will be performed by HashiCorp.
If you are interested in maintaining an unmaintained or archived plugin, please reach out to us at [email protected].