The FROM instruction defines the starting point for a container image. Every Containerfile requires it, and it normally names an existing image to use as the base. section 2.3.1
Choose the starting filesystem according to the build:
- Use FROM scratch to allocate an empty rootfs, then populate it with COPY and other build instructions. section 2.3.1
- Use an existing image, such as registry.access.redhat.com/ubi8, to pull a base image into container storage. section 2.3.1
- Treat the selected image as the base layer; subsequent instructions operate on its mounted rootfs and add content. section 2.3.1
- Place FROM first; use it multiple times when creating multiple build stages. section 2.3.1
Build an HTTP application image
Create a Containerfile containing FROM ubi8/httpd-24 followed by COPY index.html /var/www/html/index.html, then run podman build -t quay.io/rhatdan/myimage ./myapp. The build pulls the base image, copies the application file, commits the result, and tags the new image. section 2.3.2
Table 2.6 Containerfile directives that update the image (view table figure)
Compare FROM with other Containerfile directives that update the image or define runtime behavior. section 2.3.1
