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Hello World Example

This tutorial will demonstrate how to get started with Rancher Desktop by pushing an app to a local Kubernetes cluster.

Rancher Desktop works with two container engines, containerd and Moby, the open-sourced components of the Docker ecosystem. For nerdctl, use the containerd runtime. For docker, use the dockerd(moby) runtime.

Example#1 - Build Image & Run Container

Create a folder

mkdir ../hello-world
cd ../hello-world

Create a Dockerfile with the command below

FROM alpine  
CMD ["echo", "Hello World!!"]

Build and run the image for verification purposes

nerdctl build --tag helloworld:v1.0 .
nerdctl images | grep helloworld
nerdctl run --rm helloworld:v1.0
# Remove the image
nerdctl rmi helloworld:v1.0

Example#2 - Build Image & Deploy Container to Kubernetes

Make sure that you switch the Container Runtime setting in the Kubernetes Settings panel to either dockerd or containerd as needed.

Create a folder and add a sample index.html file as follows

mkdir ../nginx
cd ../nginx
echo "<h1>Hello World from NGINX!!</h1>" > index.html

Create a Dockerfile with the command below

FROM nginx:alpine
COPY . /usr/share/nginx/html

Build image from code locally

⚠️ Note: Please note that you need to pass the flag --namespace to the nerdctl build command, so that nerdctl builds the image and then makes it available in the namespace.

nerdctl --namespace build --tag nginx-helloworld:latest .
nerdctl --namespace images | grep nginx-helloworld

Deploy to Kubernetes

Run below command to create and run a pod using the image built in the previous step.

⚠️ Note: Please note that you need to pass the flag --image-pull-policy=Never to use a local image with :latest tag, as :latest tag will always try to pull the images from a remote repository.

kubectl run hello-world --image=nginx-helloworld:latest --image-pull-policy=Never --port=80
kubectl port-forward pods/hello-world 8080:80

Point your web browser to localhost:8080, and you will see the message Hello World from NGINX!!. If you prefer to stay on the command line, use curl localhost:8080.

Delete the pod and the image

kubectl delete pod hello-world
# Remove the image
nerdctl --namespace rmi nginx-helloworld:latest