Best Practices for Writing Dockerfiles

Over the last few years, adoption of Docker and Kubernetes has grown in leaps and bounds. Vast majority of developers is developing microservices and deploying them into containers. One of the most important aspect that people do not realize is that, the containers needs to be lightweight in nature. Also, while building containers, one needs to account for certain aspects like reducing build time while doing incremental builds, produce images in consistent ways, performing clean builds, maintain them properly, etc. To achieve all this, one needs to follow certain practices while writing Dockerfiles.
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Run Azure DevOps Private Agents in Kubernetes Clusters

Since in last post, we discussed on how to run Azure Pipelines agents as docker containers and configure them accordingly, the next step would be to run them on the Kubernetes platform. This kubernetes cluster can be on-premise and/or cloud and could be self managed or managed by the cloud service provider itself.

One of the reasons you may want to run them on Kubernetes is because you want better utilization of your kubernetes cluster. Another reason might be to leverage your existing knowledge of the kubernetes platform and work on it. Another reason would be to not use Microsoft hosted agents, as by default you would get only 1800 minutes of agent time to utilize, for free accounts.
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Running Azure DevOps private agents as docker containers

To run the build or deployment jobs in Azure DevOps or Azure Pipelines (formerly known as TFS and VSTS respectively), an agent is required. Microsoft provides the different types of the agents and they are hosted and managed by Microsoft only. However, it is advisable to host your own private agent for various reasons other than the cost. Microsoft provides the facility of installing agent on various OS’es like Windows, Linux, Mac OS etc. They have done a good job in terms of documentation, however you still need to perform few steps in order to set it up correctly.
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Configure CI/CD in Azure Pipelines to deploy docker containers as Azure Web App

Few days back, we learned about how to publish Azure Container Instances where-in we can deploy either a container or group of containers and use the same. Azure Web App for Containers allows you to not only run your containers but it also brings forth the PaaS innovations for the Web App. So it brings best of the both worlds together. It also allows you to not worry about the maintaining an container orchestrator mechanism. You can prefer to package their code and dependencies into containers using various CI/CD systems like Jenkins, Maven, Travis CI or VSTS, alongside setting up continuous deployment web hooks with App Service.

In this blog post we’ll learn more about how to deploy .NETCore application packaged as docker container and using CI/CD in Azure Pipelines (Formerly VSTS).Read More »

Configure CI/CD for Azure Container Instances using Azure / Azure DevOps Pipelines

Containers are fast becoming the preferred way to package, deploy, and manage cloud applications. Azure Container Instances offers the fastest and simplest way to run a container in Azure, without having to manage any virtual machines and without having to adopt a higher-level service.

Azure Container Instances is a great solution for any scenario that can operate in isolated containers, including simple applications, task automation, and build jobs. Also, Azure Container Instances supports the deployment of multiple containers onto a single host by using a container group aka pods in terms of Kubernetes. Multi-container container groups or Pods are useful when building an application sidecar for logging, monitoring, or any other configuration where a service needs a second attached process.
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Use SSL Certificates for Dotnet Core Application in Docker Containers

Using SSL to secure incoming and outgoing traffic from your server is always recommended. When you are developing locally or testing on a server, whether it is Windows or Macintosh or some distribution of Linux like CentOS, fedora, Ubuntu etc, its easy to put the certificate in one of the local directories and then ask server to use the same. However this becomes a little bit different if you are using Containers. Since Docker is the most popular container technology, it has become almost synonymous with containers. When using containers, you can many choices:
1) Map a local volume containing certificate files to the container and then refer to it from inside container
2) Copy certificate directly inside Container during image build process and then refer to it Read More »

Remove old docker images from Azure Container Registry

As part of the Continuous Integration process, new builds are generated which contains certain enhancements or modification or bugfixes. For a containerized application deployment, docker images are created as part of builds which then needs to be uploaded to one of the container registries. Over the time, the registry will get filled up. Also as one use more and more space on the container registry, one needs to pay more and more.

There are no inbuilt commands or utilities provided by Docker for this. You have to write complex scripts for doing it. Fortunately, in latest round of the Azure CLI update, Microsoft has added some commands to do this. However, it can be cumbersome to select and remove docker images one at a time. Read More »

Detecting if dotnet core app is running inside docker container

In old days (not so old, albeit like a one or two year(s) ago), we used to insert a docker environment variable like IS_DOCKER_CONTAINER using dockerfile in docker images. This was used to determine if an application is running inside a docker container or not. This helped to set certain attributes of the application like logging level and methods, modify certain environmental settings etc and helped controlling behavior of the application. It can also be useful in other situations like to determine whether you want to run selenium tests or not (as selenium web drivers would not be available inside docker container) to run as part of the integration testing. Read More »