Apptainer: Difference between revisions

==Building an Apptainer Container/Image==

Apptainer "images" can be created in the following formats:

Using an <code>SIF</code> image is recommended as disk performance (from the container image) will be faster than storing each file, etc. separately on Alliance cluster filesystems (which are set up to handle large files and parallel I/O). Using an <code>SIF</code> file instead of a sandbox image will also only use a quota file count amount of 1 instead of thousands (e.g., images will typically contain thousands of files and directories).

In order to build a "sandbox" directory instead of an <code>SIF</code> file instead of providing an <code>SIF</code> file name, instead provide <code>--sandbox DIR_NAME</code> or <code>-s DIR_NAME</code> where <code>DIR_NAME</code> is the name of the to-be-created-directory where you want your "sandbox" image. For example, if the <code>apptainer build</code> command to create an <code>SIF</code> file was:

Within an account, using a "sandbox" directory will consume significant amounts of both disk space and file count quotas, thus, if read-write access to the underlying image is not normally required, you are advised to use an <code>SIF</code> instead. Additionally, using an <code>SIF</code> file will have higher disk access speeds to content contained within the <code>SIF</code> file.

'''NOTE:''' This section only discusses some basics of creating a simple compressed, read-only <code>SIF</code> file container image. See the [https://apptainer.org/docs Apptainer documentation] for more advanced aspects of building images.