Should the learning management system through which I access an e-book be listed as a container?

No. As explained in another post on the Style Center, “A Web site is a container when it is the platform of publication of the particular version of the work you consult. It is not a container when it is a passive conduit providing access to the work” (Gibson). If you access an e-book through a learning management system, such as Blackboard, the course platform is not the platform of publication for the e-book, so the course platform is not a container. You would thus cite the e-book as shown in the following example:

Saba, Robert. Composing to Communicate: A Student’s Guide. E-book, Cengage, 2017.

Work Cited

Gibson, Angela. “When Is a Web Site a Container?” The MLA Style Center, Modern Language Association of America, 17 Aug. 2017, style.mla.org/web-sites-as-containers/.