codewithmukesh
what and why? 🤔
DOCKER
FOR .NET DEVELOPERS
what is docker?
why do you need it?
& some basic docker commands
mukesh murugan
@iammukeshm
codewithmukesh
Imagine..
Imagine that you are all set with your new .NET
Application and ready to deploy it to higher
environments!
Everything is working as
expected on my
development machine!
Let’s deploy this thing!
mukesh murugan
@iammukeshm
codewithmukesh
But then you realize that
there are several issues
when deployed to other
environments, or worst
case, in production!
We have all faced this at
some point, right?
mukesh murugan
@iammukeshm
codewithmukesh
Then happens the famous..
" But it works on my machine!"
mukesh murugan
@iammukeshm
codewithmukesh
What could be the potential
reasons?
Packages Dependencies
Framework Issues
Misconfigured Environment Variables
OS Level Mismatches
Inconsistent System Configurations
Service Interactions
You might have forgotten to set a feature flag!
And many other things that you never expected!
mukesh murugan
@iammukeshm
codewithmukesh
The Solution?
We need a standardized way to package our .NET
application along with everything it needs to function,
in any environment.
Docker is a tool that allows you to build, test and
deploy applications quickly, using containers and
images.
mukesh murugan
@iammukeshm
codewithmukesh
Docker..
Docker essentially can package your application and
all its related dependencies into Docker Images.
These images can be pushed to a central repository,
for example, Docker Hub or Amazon Elastic
Container Registry, and can be run or any server!
mukesh murugan
@iammukeshm
codewithmukesh
Each image represents a blueprint for an
application. These Images can be downloaded to
any location and you can have them run as
containers, which are isolated processes running on
your machine.
Here is how a bunch of microservices run on
Docker!
mukesh murugan
@iammukeshm
codewithmukesh
Dockerfile
Here is a sample Dockerfile, which acts as instructions for Docker to build an
image from a .NET application.
It downloads the required .NET SDK (for build), copies all the project content
to a working directory, and publishes the required DLLs in Release mode. You
can also set the Environment variables for your application here.
You would have to have docker-desktop running on your machine, and this
dockerfile would sit right beside your .csproj file.
mukesh murugan
@iammukeshm
codewithmukesh
Basic Commands
To get started, ensure that you have docker-desktop downloaded and
running on your machine. Here are some important docker cli commands
that you must know.
docker version : gets the current version of the docker instance.
docker ps : lists all the running containers.
docker images : lists all available images locally on your machine.
docker run <image:tag> : spins up a new container using an image. For
example, 'docker run redis:latest'
docker pull <image:tag> : pulls an image with a specific tag onto your
local machine. For example, 'docker pull redis:latest'
docker stop <container name / id> : stops a particular container.
docker rm <container name / id> : removed the container from your
instance.
docker rmi <image> : can remove the copy of the image from your local.
docker exec <container name> : helps you run a command inside your
container. I use 'docker exec -it redis bash' a lot.
docker build -t <image_name> <dockerfile_path> : using the
instructions from the dockerfile, build a new image with a custom name
and tag. Remember the dockerfile we created earlier? You can build an
image with it --> 'docker build -t HelloWorld:1.0 .' The dot (.) at the end is
pretty important, since it specifies the location of your dockerfile. In my
case, I was running the command from the directory where the dockerfile
exists.
mukesh murugan
@iammukeshm
codewithmukesh
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mukesh murugan
@iammukeshm
codewithmukesh
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