Ask HN: SaaS startup releasing an open-source version?

I would love to hear your thoughts about running a commercial SaaS enterprise with an open-source offering. For example, Instructure Inc. created the open-source Canvas LMS, but they charge for the enterprise hosted version. Are you aware of any big-name startups that did something similar?

I’m seriously considering releasing a free version of my software (for marketing purposes) as an open source product, in order to generate buzz and interest (apart from the goodwill), and then create an enterprise closed-source version of it with fully hosted/managed features that I can charge for. My first question is, what licence would I release the open source version under, in order to protect my commercial enterprise, while still making it useful to others?