Open-source lightweight app deployment engine company Docker has raised $15 million in a Series B round led by Greylock Partners with participation form Insight Venture Partners and return backers Benchmark, Trinity Ventures, and Jerry Yang. The company claims 400,000 downloads, 300 contributors, and over 5,000 published applications from companies like Google, eBay, Yandex, Mailgun, CloudFlare and Baidu, [Source: Docker]