Docker has grown wildly in the last few years. It’s gone from a fledgling startup to a billion-dollar company, and now it’s got the attention of the enterprise. A number of changes have happened at Docker too – there’s been a leadership transition as well as Docker giving many of its core components over to the open source community to be managed there. All this change has set the stage for the next chapter in Docker history. Docker at DockerCon 2017 announced a new initiative that is aimed to take containers to the next frontier through the Moby Project.
The Moby Project has bold ambitions. It seeks to expand containers to include not only applications, but also core system components as well on an operating system. Docker says, “Moby is a framework to assemble specialized container systems. It has a library of containerized components and a framework for assembling these components into a standalone container platform.” Traditionally, containers were subsequent to an operating system – it would boot, load the container engine, then load containers that hosted applications like databases, message queues, and web servers. Moby intends to containerize things like DHCP servers, DNS servers, and so on such that they too can be pulled and plugged in much the same way of traditional containers to build custom operating systems.… Read more
Containers are cool – and everyone and their mother is trying to get on board with them. While many applications are natural fit for containers in many cases, it feels like some applications are forced into containers so vendors can say, “Hey look at me! I do containers too!” This is particularly true of database vendors who are using container hype to sell their software. Imagine for a moment this not so unrealistic anecdote: your CEO just got back from a conference and heard all the really cool things that you can do with containers. He or she gives the edict to IT to containerize everything because he or she heard the sales pitch: “Containers can unify DevOps pipelines for databases, apps, and resources in IT. Containers are easier and faster to setup and install compared to virtual machines. Containers lower management needs and hardware requirements relative to VM’s by reducing infrastructure. All of this means huge costs saving. Wow! Aren’t containers great!?” So now, you’re faced with this edict and you have to figure out how to take a massive MS-SQL cluster, and containerize it… or do you?
Perhaps not on this scale, but this scenario is one that enterprises are facing every day.… Read more
ASP.NET Core offers the exciting ability to develop, test, and deploy on different platforms. In this 1-hour webinar with Jason Bell, you will learn how to use Docker to create a consistent testing and deployment target for ASP.NET Core applications. You will also examine a real-world case study application that uses Amazon’s EC2 Container Service.
In this webinar, you’ll learn:
Did you like this webinar? Check out our ASP.NET Core with Docker live, 2-day virtual course.
To perform the demonstrations as shown during the webinar, you must have the Docker tools installed for your platform (the Community Edition is fine). You can find a download for each supported platform here: https://www.docker.com/get-docker.
The GitHub repo used in this article can be found here.
One of the lesser known features of Docker is its ability to do cloud builds based on WebHooks from GitHub and Bitbucket. Bitbucket and GitHub integration works in Docker natively so that when code is pushed to a repository, Docker will download and deploy the code and build the image on Docker hub automatically with Docker Automated Builds.
Setting it up is easy. Logon to Docker Hub, and you can select from the Create menu, select Create Automated Build.
This will take you to a page with two big buttons – one for Github and one for Bitbucket. Both work the same way – You first link your Github account with the Docker Hub account. This process is pretty straight forward. Once you link the accounts, you can now select the GitHub or Bitbucket repository you want to use. Once you select the repository, you can now create the build integration. Name the Docker Hub repository whatever you want then click Create.
Now, you can git push your app to GitHub or Bitbucket with git, and it will then trigger a build on Docker Hub. The push will need to include a Dockerfile in the root of the git repo.… Read more
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
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
Azure Container Service is out of preview and ready for prime time, Microsoft announced Tuesday. The service gives businesses a simple way to run their containerized applications in the cloud; it’s been available in preview since the end of last year.
Microsoft is offering Azure Container Service with a choice of two orchestration systems: Docker Swarm and Mesosphere’s Data Center Operating System, or DC/OS.
Microsoft also announced it is collaborating with Mesosphere and a number of other technology companies on an open-source version of DC/OS. DC/OS is powered by Apache Mesos technology, which major players like Twitter and Yelp already use to build and run distributed systems and applications. It can be operated from the web or command line, and includes an “app-store-like” environment for selecting and adding new components, according to a Microsoft blog post announcing the project.
Enterprises have moved quickly to adopt containers over the past couple of years, with Docker the leading vehicle for managing them. Containers allow for running multiple local development environments from the same host across different software and operating systems. Developers can more easily test and deploy projects uniformly, without using space-guzzling virtual machines.
Docker is an application virtualization service based on features of the Linux operating system. It provides a way to share a host OS, and using a virtualized filesystem, install and run Linux based apps in an isolated environment called a container. The following diagram shows how Docker is different from Virtual Machines.
Docker is driven by a daemon running on the Host OS. A client (either command line or UI using an open source tool like Kitematic) issues commands to the daemon to build, install, or execute an application image in a container.
As shown in the diagram above, the Docker daemon runs on a host machine. The user does not directly interact with the daemon, but instead through the Docker client.
The Docker client, in the form of the docker binary, is the primary user interface to Docker. It accepts commands from the user and communicates back and forth with a Docker daemon.
To understand Docker’s internals, you need to know about three components:
A Docker image is a read-only template. For example, an image could contain an Ubuntu operating system with Apache and your web application installed.… Read more