One of the most anticipated announcements in the Docker space when it comes to building images is Multi-Stage builds because of the huge benefits it gives to CI/CD pipelines in DevOps. Before this announcement, building software in a container usually involved creating a container with all the SDK’s and compilers in the container, uploading code into the container, compiling it, creating a drop, then building another container with just the runtime that sucks in the compiled code to run. This pattern required an external tool and storage to build the container image so it was more burdensome.
Multi-Stage builds on Docker though provide a mechanism for moving the output of a build from a builder container into another container that can be used for running. Consider the following the example. This Dockerfile builds a .NET core app in one container then packages it in another.
#Builder FROM microsoft/dotnet:1.1.2-sdk-jessie COPY /myapp /myapp RUN dotnet restore ./myapp && \ dotnet build -c release ./myapp && \ dotnet publish -c release -o pubdir ./myapp #Final Build FROM microsoft/dotnet:1.1.2-runtime COPY --from=0 /myapp/pubdir /myapp ENV ASPNETCORE_URLS http://+:80 ENTRYPOINT ["dotnet", "/myapp/myapp.dll"] EXPOSE 80
This file has two FROM instructions, which in a traditional Dockerfile only one is a allowed.… Read more
Many organizations, not wanting to rewrite applications, are figuring out how to take apps and containerize them for the cloud. Older operating systems are either end-of-life or approaching the end-of-life. Likewise, applications are increasingly being migrated to cloud hosts. The need to do this is as pressing as ever and containers offer a simple, viable solution to make this happen. Windows Containers on Docker bring to bear is the ability to “modernize” legacy .NET apps.
Containers by design improves application density on a given hardware by eliminating the need for redundant operating system installs. Unlike virtual machines that provide hardware abstraction on which a guest OS and apps are installed, containers provide operating system level abstraction, and apps run on top of that. This in effects removes all the CPU and memory requirements needed to run individual OS’s for apps and consolidates this into a single operating system (or multiple if running on a cluster). In the end, the savings are realized in terms of disk space, CPU, and memory consumption.
Microsoft like many other organizations have embraced containers, and have formed a deep partnership with Docker to provide Windows containers. Moving legacy apps to containers is nuanced, and there is no one-size-fits-all approach, but this guide is intended to provide a high-level approach to getting your legacy ASP.NET apps into Windows containers.… Read more
One of the most anticipated features of Windows Server 2016 is container services. Microsoft has worked closely with Docker to create this exciting new feature for on-premise CaaS. Wintellect senior consultant Blaize Stewart has created a webinar in which you can learn all about the new technology, the types of containers you can deploy on Windows Server 2016, and the Docker tools available to run and manage them.
Click on the video above to view, and share your feedback in the comments.… Read more
Azure Container Services is one of the hottest implementations of Containers-as-a-Service for many reasons. Unlike many other CaaS implentations, ACS is pure Docker, yet it is fully backed and supported by many popular tools for Azure administration. When deployed, it is production ready, secure, and easily scaled.
This one-hour webinar will demonstrate the power and efficiency of ACS and how you can use it for your applications. Click on the video above to view, and give us your feedback in the comments.… Read more
Want to learn more about how containerization helps to enable advanced DevOps solutions using Docker? Blaize Stewart just completed a new Webinar called An Introduction to Docker that shows how to utilize the Docker Hub to find pre-built images that can be used as is or as a basis for your own images. He then shows how to build and deploy your own images for use in a Docker container.
He also shows how the Docker ecosystem can be used to build a scalable deployment model for your DevOps solutions. For more information, watch the complete video or check out our 2-day live virtual course “Docker Head to Toe“.… Read more