Getting Started With runC

Runc binary

Install runc: curl -Lo runc https://github.com/lalyos/global-hack-day-3/releases/download/v0.3/runc && chmod +x runc && mv runc /usr/local/bin/

You can check if its available:

runc --help

runC needs 3 thing to start container:

rootfs dir with the whole filesystem
config.json
runtime.json

We will create the rootfs, by exporting a docker container...

Export a container

To be able to export a container, first you have to create one:

docker create --name cont1 alpine sh

Now you are ready to export it into a tar file: alpine.tar

docker export cont1 > alpine.tar

It can take some time, be patient...

You can remove the container: docker rm -f cont1

To create the rootfs dir, just untar alpine.tar into a directory named roots: mkdir rootfs; tar -xf alpine.tar -C rootfs

Create specification files

With the Rootfs ready you need to generate 2 spec files. runC can create a default file based on the rootfs directory using:

runc spec

Start your first runC container

You are ready to start the runC container:

sudo runc start

Because we specified the export container to start sh you should be in a alpine prompt. For example you'll now have access to apk, Alpine's package manager.

apk --version

cd <directory>	Change directory
ls	List directory
echo 'contents' > <file>	Write contents to a file
cat <file>	Output contents of file

i	In Command Mode	Change into Insert Mode, you can now insert and edit text in the file
esc	In Insert Mode	Change into Command Mode, you can now execute commands
:wq	In Command Mode	Save and Exit

Welcome!

Congratulations!

You've completed the scenario!

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