Packer Fundamentals

Packer turns an image recipe into a machine image. You describe the build in a template. Packer starts a temporary machine or container, configures it, creates an artifact, and cleans up the temporary build resources.

The artifact might be a cloud machine image, a virtual machine image, or a container image. The exact result depends on the builder plugin you select. Packer coordinates the build, while the target platform owns the resulting image.

Why image builds matter

Installing an operating system and application dependencies during every deployment adds time and uncertainty. A prebuilt image moves that work into a controlled build stage.

Teams often call an approved base image a golden image. The name means the image is a known starting point. It does not mean the image stays secure forever. You still need to rebuild, test, distribute, and retire images through a separate lifecycle.