My previous post was about doing continuous deployment of Kubernetes application using Skaffold to a Minikube cluster. In the recent version of Docker for Desktop (Mac & Windows), there is built in support for Kubernetes. We can decide to deploy multi container applications to a single node local cluster and choose the type of Orchestrator. Currently Docker for Mac supports Docker Swarm and Kubernetes. In this post, I will demonstrate how we can use Skaffold to deploy to a Kubernetes cluster instead of Minikube. We will perform following steps during the course of this post
- Enable Kubernetes support for Docker for Mac
- Set context to work with Docker for Mac
- Use Skaffold with Docker for Mac
Enable Kubernetes support for Docker for Mac
Lets first enable the support for Kubernetes orchestrator for our installation of Docker for Mac. Navigate to the preferences section of Docker. Select the Kubernetes pane, enable Kubernetes support, select default Orchestrator ad Kubernetes. Finally apply the setting as shown with steps 1 to 4 below. In my case I had these settings already enabled. If you are enabling the settings for the first time it can take a while for the Kubernetes to start the single node cluster.
Once everything is setup we should get the Docker is running and Kubernetes is running in green status.
Set context to work with Docker for Mac
We will be using the kubectl command line tool to deploy the artifacts to Kubernetes cluster. kubectl can work with multiple clusters at the same time. We need to ensure that the right context is set for the kubectl. Lets first get the list of all the clusters we have at our disposal. This is done by executing the command
kubectl config get-contexts
We can see two clusters are currently configured. The minikube cluster is the current context as shown by the * sign in front of the cluster name. We need the context to be set to the docker-for-mac context. This can be done by executing the command
kubectl config use-context docker-for-desktop
We are now ready to deploy the application to this cluster.
Use Skaffold with Docker for Mac
Once the right context is set, there is no change to be done on the skaffold side. We execute the same command skaffold dev which we did during the earlier post. Skaffold does its magic
The proper context has been selected by skaffold.
The build speed is just over 1 second to build the required Docker images. Same way the deploy is done in less than 2 seconds. I have not seen these kind of speeds while using docker compose in the past. With this, now skaffold is continuously monitoring for changes to the source code. Let test it by making some changes in the code.
As you can see from the above screen capture, the updates are really fast. It doesn’t even take 1 second to update the deployment. I commented and uncommented the same set of lines that we had used during the previous post.
As can be seen from this demo, we can seamlessly move from minikube cluster to the docker for mac cluster while working with skaffold. It does not require any configuration change to the skaffold.yaml file or to the Kubernetes manifest files. Just by setting the proper context for kubectl we can have the same productivity gains that we saw during the last post. I hope that developers working with Docker and Kubernetes find this tool useful.
Until next time, Code with Passion and Strive for Excellence.
BackgroundIn the earlier series of posts on continuous deployment of multi-container apps, I had used two containers for ASP.Net Core MVC web site and ASP.Net Core Web API. This post is a sort of continuation. In the earlier version we were using in memory database to store the data. This approach is useful in a proof of concept or a quick demo application. In an enterprise scenario we would use some sort of persistent data store to store the data. It is very easy to containerize the stateless services and web front ends. When we move towards stateful processing, things start to get interesting.Containers by their very nature are supposed to be ephemeral. This means that containers can be stopped and destroyed and a new one built and put in place with minimum setup and configuration. If we destroy the container and replace it with a new one what happens to the data stored inside the container? Can we use containers to run database related processes? How can the stateless containers c…
Problem starting SQL 2017 containerWhile working on recent blog post on Integrating SQL Server 2017 Linux with ASP.Net Core using Docker I cam across a strange behavior. I was able to run SQL Server 2017 Linux container image successfully as demonstrated here. I was able to initialize the database using the command docker run -it -p 1433:1433 \ — name sql2017 \ nileshgule/sqldbThis command runs the custom image in interactive mode based on the –i flag. We also pass the t flag to create a psudo tty terminal. The next step for me was to try the integration with Dotnet Core project. I started with updating the docker-compose file and other changes explained in the post on integration.Before I added the sql2017 as the service inside docker-compose file, I ran the SQL Server 2017 container individually using the above command & verified that the Core MVC and Core Web API we able to communicate to the database inside container.This seemed pretty easy at first. All I had to do was update…
In the previous post, we saw how to initialize a SQL Server 2017 on Linux database running inside Docker container. This post is continuation of my exploration about Docker containers for stateful applications. In this post we will explore how to integrate the SQ Server 2017 on Linux container with ASP.Net Core Web API also running inside a Docker container. We will perform following activitiesUpdate Docker compose file to build the SQL server imageUpdate Web API project to use SQL Server Database instead of In memory databaseBuild and run the application containers using Docker compose commandsQuery Data from SQL container using the MVC web front endUpdate Docker compose file to build the SQL server imageDocker provides Docker Compose as a tool for defining and running multi-container Docker applications. I already have an existing docker compose file which I have been using for my series of post on implementing continuous deployment of multi container apps. In a compose file we defi…
Originally published at www.handsonarchitect.com.