If you're a Windows shop and you're interested in containers, the good news is that container support is built into Windows Server 2016, and it's also available as an add-on for Windows 10 (Professional or Enterprise editions only).
But here's the bad news: there's no container support in Windows Server 2012, and many, many companies have yet to migrate from it to Server 2016. In fact, Server 2012's market share is likely to continue growing until 2020, even though Windows Server 2016 is slowly becoming more mainstream.
Here's another problem: Windows Server 2016 only offers limited support for SQL Server images (such as SQL Server 2016 Express), and it lacks support for Windows Authentication.
To address this problem, a small team of Microsoft veterans founded Windocks, a company that ships an independent port of Docker source that runs on Windows Server 2012, 2012 R2 and 2016, as well as Windows 8 and Windows 10. This team includes Ramesh Parameswaran, who led Microsoft teams and efforts for cross-platform and Internet technologies such as Unix shell on Windows, POSIX, and UNIX Internet Explorer, and Rama Srinivasan, who was a key member of the original development teams for Windows, Internet Information Server, and SQL Server.
A third member is Paul Stanton, who led strategies to bring Internet technologies and standards to Windows. He says Windocks is more than just containers on older versions of Windows Server. "We have also focused on SQL Server support, and support all versions from SQL Server 2008 onwards," Stanton told Virtually Speaking.
Windocks is a SAN-friendly design, he said, and supports automated delivery of SAN-based snapshots or clones from Pure Storage, NetApp, EqualLogic, and others. Customers without access to a SAN can build snapshots with the Windows file system, he added. So SQL containers can be backed up just like any other SQL Server intendances — something Microsoft's version of Docker can't easily do.
"We can drop Windocks onto any server, and integrate storage on the network and deliver data to any SQL environment," he said.
How Windocks' Containers Compare to Microsoft's Containers
The key difference between Windocks' containers and Microsoft's containers is that Windocks ones are "app-level containers," Stanton explained. "Microsoft containers include bits of the Windows OS itself, and that breaks compatibility with Active Directory, and in fact it breaks many things. Our containers maintain the break between the app and the operating system."
A disadvantage of Windocks is that it can only run Windows applications — it can't run Linux containers on Windows.
Windocks is now relatively mature, having been first released two years ago. And it has over 100 paying customers, including familiar names such as Worldpay and John Hancock, as well as smaller businesses.
The company offers a free Windocks Community Edition, which supports a maximum of two containers simultaneously. This means users can create two SQL Server (or .Net) environments on a machine, using standard Docker commands or the web application. Any Docker client from Docker Inc. will work with Windows Server, or the docker.exe file from Windocks can be used. (The Windocks web application UI, which is automatically installed, can also be used.)
Alternatively, Windocks is available using a pay-as-you-go subscription model, priced at $169 per month for up to 10 simultaneous containers, $399 per month for up to 25 simultaneous containers, or $799 for up to 50 simultaneous containers — all with database cloning and email support thrown in as well.
About half of the current Windocks instances are running in the public cloud, Stanton said — on AWS or Azure.
Now obviously if you have completed a move to Windows Server 2016, Windocks will have less appeal than if you haven't. But it's certainly a solution worth investigating if you need to work with different versions of SQL Server in containers, and you don't fancy waiting around for Microsoft to join the party more fully.
Paul Rubens is a technology journalist and contributor to ServerWatch, EnterpriseNetworkingPlanet and EnterpriseMobileToday. He has also covered technology for international newspapers and magazines including The Economist and The Financial Times since 1991.