Tag: Containers

Getting started with Windows Containers: In Practice

In previous blog post, we discussed what are windows containers, how they are different from Hyper-V containers and how they are beneficial to developers and sysadmins. We also discussed how Docker as a company has played an important part in the story. In this blog post, we will get quickly get started with installing windows containers and run our first container image by pulling it from docker registry.

Environment Pre-Requisites

  1. You must have a machine with Windows Server 2016 or Windows 10 installed on it. It may be a physical machine or the virtual machine. On the Sku side, you can have either DataCenter version or Standard version as well. Or you may also use Windows Server Core version.
  2. If its a virtual machine, make sure it has nested virtualization enabled.
  3. All windows updates should be installed on the machine.
  4. Administrative access to the machine.

Continue reading “Getting started with Windows Containers: In Practice” →

Getting started with windows Containers : Covering Basics

Windows Server 2016 introduced a new feature called Containers. By installing this feature, you can run windows containers on your server. However, these are not Linux-based and they are not related to docker (as in docker software) as well. These containers run on Windows and run Windows on the inside. Also, These conform to the Open Container Initiative (OCI). They allow you to run applications insulated from the rest of the system, within portable containers that include everything an application needs to be fully functional.

The windows containers technology from Microsoft shares many similarities with its Linux counterpart. Both provide an isolated environment for running applications without affecting the rest of the system and without being affected by that system.
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Configure CI/CD for dockerized apps using VSTS and deploy to ACS

n this blog post, we’ll discuss how to configure CI/CD for dockerized apps using Visual Studio Team Services (VSTS) and deploy to a Linux based kubernetes cluster in Azure Container Services (ACS). For building dockerized app, we’ll use .NET core and build a linux based docker image. Also we’ll be using Azure Container Services to deploy Linux based Kubernetes cluster and Azure Container Registry for providing docker registry.

Deploy Kubernetes cluster on ACS

For this, please refer to this blog post here.

Deploy Azure Container Registry

Continue reading “Configure CI/CD for dockerized apps using VSTS and deploy to ACS” →

Docker Cheat Sheet

I have spent some time to gather list of most used docker commands and below is a summary for same. These are not full blown commands, just to get you started and then you can use inbuilt command help.

Lifecycle

  • docker create Creates a container
  • docker rename Renames a container
  • docker run Creates and runs a container
  • docker rm Removes a container
  • docker update Updates a container resource limits

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Running PowerShell Core in a docker container

PowerShell core is the edition of PowerShell built on top of .NET Core. It is sometimes simplified to “CoreCLR”, though it technically includes CoreFX as well.

PowerShell Core is cross-platform, available on Windows, macOS, and Linux, thanks to the cross-platform nature of .NET Core. On PowerShell Core, $PSVersionTable.PSEdition is set to Core.

Do note that  while PowerShell Core 6.0 is cross-platform, there is also a PowerShell Core 5.0/5.1 released exclusively as part of Nano Server. In this blog post, we’ll learn how to run PowerShell core in a docker container. Continue reading “Running PowerShell Core in a docker container” →

Remove images from Docker Images

You can remove an image using its short or long ID, its tag, or its digest in the Docker. For this we have to use the command:

docker rmi [OPTIONS] IMAGE [IMAGE...]

Where Options are:
-f, –force Force removal of the image
–help Print usage
–no-prune Do not delete untagged parents

Let’s see how this works. You cannot delete an image if it has been used to spawn containers or child images based on it. You would likely see an error message which resembles following:

Error response from daemon: conflict: unable to remove repository reference “mogo/ubuntu:telnet” (must force) – container 4888c45aa31c is using its referenced image a955c52ec9ec

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Change directory to store containers and images in Docker

As discussed in one of the previous posts, docker is more focused on ease of use and not so much on the disk space efficiency out of the box. However, it is our responsibility to maintain adequate free space on hard disk and also do some kind of standardization. DevOps is not only about automation but it is also about standardization of process thereby removing any gotchas or discrepancy in the configuration. For example, we may like to store docker images in a separate directory that may be located on a mounted device storage or some other easy to navigate configuration.

By default, docker store containers and images in /var/lib/docker by default:

Default directory for containers and images in Docker
Default directory for containers and images in Docker

Continue reading “Change directory to store containers and images in Docker” →