Understanding SQL Server Containers

This blog takes a fresh look at the role containers can play for SQL Server, and compares Microsoft and WinDocks support for SQL Server containers.

Eighteen months ago, Microsoft announced plans to add Docker container support to Windows Server 2016. The announcement added emphasis to Microsoft’s growing focus on Linux and open source tooling. In the months that followed, .NET core was open sourced, Microsoft and Red Hat formed an alliance, and plans to port SQL Server to Linux were announced. Containers are just around the corner for the Windows community, so let’s take a closer look at the use of SQL Server containers and how the WinDocks and Microsoft containers compare.

Relational DB Containers Are Popular for Dev and Test on Linux

We begin by looking at the use of MySQL on Linux Docker containers. MySQL and Postgres are among the most popular container images on the Docker Hub (https://hub.docker.com ). DB containers are used to deliver identical, isolated, sandboxed environments for development and test. Data is included in the container or can be mounted. Containers are instantiated in seconds, with a team supported on a shared VM. Adoption of Docker is accelerating, and a RightScale survey shows Docker will soon be the leading toolchain for DevOps, surpassing Chef and Puppet (RightScale’s State of Cloud 2016 Report).

Containers, Images, Repos, and Automation

Containers involve several elements. Containers provide process and user isolation for applications and are built with DockerFiles which specify the code, configuration, and data to be used. Once built, containers can be saved as Images, which are used to support teams with identical instances, and are listed in a public of private repository or Repo. Containers are designed for automation, which explains why Microsoft emphasizes use of PowerShell for container operations.

Containers are fast, and lightweight. A SQL Server container can be created in seconds, as it doesn’t require an OS to boot as with a VM. Sharing a common operating system, container hosts will commonly service 3-5x more workload when compared to VMs!

The Importance of the Docker API

Just as the Win32 API dominated the landscape for desktop applications, Docker is rapidly becoming the industry standard API for container management. Microsoft is implementing the API for Windows and is involved in the formal standardization through the Open Container Initiative (http://www.linuxfoundation.org ). Docker-based systems will benefit from industry-wide support with hosted services on AWS, Azure, and other clouds, and third-party tools built to facilitate Docker containers with Monitoring, Logging, Cluster orchestration, and other services.

Microsoft and WinDocks Containers Compared

Microsoft is poised to fulfill Docker support with Windows Server 2016 later this summer. Microsoft’s design features an option to support containers on either the Windows Server 2016 "core" or a headless server called Nano. As of the date of this article, Microsoft has been relatively quiet on plans for SQL Server image support, although there is a SQL Server 2014 Express image available on Dockerhub. How users are expected to add and attach databases to the SQL Server container, other than using manual GUI based tools, is unclear.

Editor's note, post DockerCon. Microsoft chose to promote their first SQL Server image at DockerCon, which is based on a yet-to-be-released SQL Server port to Linux. This suggests that Microsoft's SQL Server group has decided to focus on Linux for future SQL Server container support (and only for SQL Server 2016).

WinDocks is comprised of former Microsoft engineers who have ported the Docker engine to Windows, using an open source container design from Uhuru software. WinDocks was released earlier this year, and supports Windows 8, Windows 10, as well as Windows Server 2012 and Windows Server 2016. WinDocks also supports SQL Server 2008 (and r2), 2012, and 2014, and SQL Server 2016, all editions. WinDocks has focused on SQL Server container support and includes DockerFile commands for Adding and Mounting databases, and support of storage systems. WinDocks also offers a free Community Edition available for download.

To access Microsoft and WinDocks downloads visit:

https://www.microsoft.com/en-us/evalcenter/evaluate-windows-server-technical-preview

http://www.windocks.com/lps/communityedition

Conclusions

The growth in use of containers with MySQL and Docker for agile and DevOps processes, and Microsoft’s support, argues that SQL Server containers will rapidly become mainstream. If you’re ready to start there are options available, whether you use Windows 8 or Windows 10!