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 blank Dockerfile
On Windows, Create a blank file named Dockerfile
On Linux, You can use below command to create a blank Dockerfile
vi Dockerfile
Populate the Dockerfile with the command below
FROM alpine
CMD ["echo", "Hello World!!"]
Build and run the image for verification purposes
- nerdctl
- docker
nerdctl build --tag helloworld:v1.0 .
nerdctl images | grep helloworld
nerdctl run --rm helloworld:v1.0
# Remove the image
nerdctl rmi helloworld:v1.0
docker build --tag helloworld:v1.0 .
docker images | grep helloworld
docker run --rm helloworld:v1.0
# Remove the image
docker 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 blank Dockerfile
On Windows, Create a blank file named Dockerfile
On Linux, You can use below command to create a blank Dockerfile
vi Dockerfile
Populate the 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 k8s.io to the nerdctl build command, so that nerdctl builds the image and then makes it available in the k8s.io namespace.
- nerdctl
- docker
nerdctl --namespace k8s.io build --tag nginx-helloworld:latest .
nerdctl --namespace k8s.io images | grep nginx-helloworld
docker build --tag nginx-helloworld:latest .
docker 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
- nerdctl
- docker
kubectl delete pod hello-world
# Remove the image
nerdctl --namespace k8s.io rmi nginx-helloworld:latest
kubectl delete pod hello-world
# Remove the image
docker rmi nginx-helloworld:latest