Add some CRI-agnostic image build documentation

docs/README.md

@@ -26,6 +26,8 @@
 
 * **Reusing the Docker Daemon** ([reusing_the_docker_daemon.md](reusing_the_docker_daemon.md)): How to point your docker CLI to the docker daemon running inside minikube
 
+* **Building images within the VM** ([building_images_within_the_vm.md](building_images_within_the_vm.md)): How to build a container image within the minikube VM
+
 #### Storage
 
 * **Persistent Volumes** ([persistent_volumes.md](persistent_volumes.md)): Persistent Volumes in Minikube and persisted locations in the VM

docs/building_images_within_the_vm.md

@@ -0,0 +1,31 @@
+# Building images within the VM
+
+When using a single VM of Kubernetes it's really handy to build inside the VM; as this means you don't have to build on your host machine and push the image into a docker registry - you can just build inside the same machine as minikube which speeds up local experiments.
+
+## Docker (containerd)
+
+For Docker, you can either set up your host docker client to communicate by [reusing the docker daemon](reusing_the_docker_daemon.md).
+
+Or you can use `minikube ssh` to connect to the virtual machine, and run the `docker build` there:
+
+```shell
+docker build
+```
+
+For more information on the `docker build` command, read the [Docker documentation](https://docs.docker.com/engine/reference/commandline/build/) (docker.com).
+
+## Podman (cri-o)
+
+For Podman, there is no daemon running. The processes are started by the user, monitored by `conmon`.
+
+So you need to use `minikube ssh`, and you will also make sure to run the command as the root user:
+
+```shell
+sudo -E podman build
+```
+
+For more information on the `podman build` command, read the [Podman documentation](https://github.com/containers/libpod/blob/master/docs/podman-build.1.md) (podman.io).
+
+## Build context
+
+For the build context you can use any directory on the virtual machine, or any address on the network.