Working with Containers
nerdctl is a Docker-compatible CLI for containerd. The primary goal of nerdctl is to facilitate experimenting with cutting-edge features of containerd that are not present in Docker.
Moby is an open-source project that was created by Docker to enable and accelerate software containerization. Components include container build tools, a container registry, orchestration tools, and a runtime, and more. The Docker CLI uses the Moby runtime.
Running Containers​
To run a container with the default bridge CNI network (10.4.0.0/24):
- nerdctl
- docker
nerdctl run -it --rm alpine
docker run -it --rm alpine
To build an image using BuildKit:
- nerdctl
- docker
nerdctl build -t foo /some-dockerfile-directory
nerdctl run -it --rm foo
docker build -t foo /some-dockerfile-directory
docker run -it --rm foo
To build and send output to a local directory using BuiltKit:
- nerdctl
- docker
nerdctl build -o type=local,dest=. /some-dockerfile-directory
docker build -o type=local,dest=. /some-dockerfile-directory
Docker Compose​
Docker Compose is a tool for defining and running multi-container Docker applications.
- nerdctl
- docker
The nerdctl-compose CLI is designed to be compatible with docker-compose:
nerdctl compose up -d
nerdctl compose down
The compose command in the Docker CLI supports most of the docker-compose commands and flags. It is expected to be a drop-in replacement for docker-compose.
docker compose up -d
docker compose down
Exposing a Port​
To expose port 8000 for a container:
- nerdctl
- docker
nerdctl run -d -p 8000:80 nginx
docker run -d -p 8000:80 nginx
You can then access the container via the browser here: http://localhost:8000/.
Note: By default the exposed ports are accessible on all network interfaces on macOS and Linux. However, on Windows, the exposed ports are currently only accessible through the localhost network interface (see issue #1180). As a workaround, you can configure a portproxy on the windows host to expose the port to additional network interfaces.
netsh interface portproxy add v4tov4 listenport=8080 listenaddress=0.0.0.0 connectport=8080 connectaddress=localhost
Targeting a Kubernetes Namespace​
You may also target a Kubernetes namespace with the --namespace parameter with containerd. Please note that docker doesn't use namespaces.
- nerdctl
nerdctl --namespace k8s.io build -t demo:latest /code/demos/rd/anvil-app
nerdctl --namespace k8s.io ps