+# CI Packer
+
+[Packer][1] is a tool for automatically creating VM and container images,
+configuring them and post-processing them into standard output formats.
+
+## Building
+
+You'll need to [install Packer][2], of course.
+
+The Packer configuration is divided into build-specific variables,
+output-specific templates and a set of shared provisioning scripts. To do a
+specific build, combine the template for the desired output artifact type with
+a variable file. To build a new basebuild instance the following would be done:
+
+```
+packer build -var-file=vars/cloud-env.json -var-file=vars/centos.json templates/basebuild.json
+```
+
+**NOTE:** vars/cloud-env.json is a gitignored file as it contains private
+information. There is a vars/cloud-env.json.example file that may be used as a
+base for creating the one needed.
+
+This would build a bootable image in the project's CI cloud environment.
+
+From a high level, the builds:
+
+* Boot a specified base image in the cloud
+* Run a set of shell scripts, listed in the template's shell provisioner
+ section, to do any configuration required by the builder.
+* Execute a shutdown of the running instance
+* Execute a 'nova image-create' operation against the shutdown instance.
+* Perform a 'nova delete' operation against the shutdown instance.
+
+[1]: https://www.packer.io/
+[2]: https://www.packer.io/intro/getting-started/install.html