NERDCTL AND CONTAINERD ON SLACKWARE-CURRENT
============================================

1. Overview  
-----------

This document provides a step-by-step guide for running containers on Slackware using containerd and nerdctl.  
Containerd is a high-level container runtime that uses runc for low-level execution.  
Nerdctl is a Docker-compatible CLI for containerd.  

This setup avoids Docker’s heavier dependencies and does not require systemd.  

To begin, install the following packages via SlackBuilds:  

- go-md2man
- runc  
- cni-plugins  
- containerd  
- nerdctl  

Modified SlackBuilds used in this guide are available at:  

    https://git.sr.ht/~r1w1s1/slackbuilds/tree/main/item/modified  

2. Starting containerd  
----------------------

The SlackBuild for containerd installs an init script at /etc/rc.d/rc.containerd.new.  

Enable and start containerd manually:  

    chmod +x /etc/rc.d/rc.containerd  
    /etc/rc.d/rc.containerd start  

To run containerd at boot, add the following lines to /etc/rc.d/rc.local:  

    if [ -x /etc/rc.d/rc.containerd ]; then  
      /etc/rc.d/rc.containerd start  
    fi  

3. Running nerdctl as root  
--------------------------

Since there is no systemd on Slackware, nerdctl is typically run as root via sudo.  
If you do not have sudo configured, see:  

    https://git.sr.ht/~r1w1s1/code-notes/blob/main/notes/Enable_Sudo_on_Slackware.txt  

Example:  

    sudo nerdctl run hello-world  

Expected output confirms that the runtime and networking are working.  

4. Networking with CNI plugins  
-------------------------------

The cni-plugins package installs networking helpers under /usr/libexec/cni.  
On first use, nerdctl creates /etc/cni/net.d/nerdctl-bridge.conflist and a bridge interface nerdctl0.  

Verify networking inside a busybox container:  

    sudo nerdctl run --rm -it busybox sh  
    / # ping -c2 8.8.8.8  

You should see successful pings.  

5. Exposing services  
--------------------

Run a container with ports mapped to the host:  

    sudo nerdctl run -d -p 8080:80 nginx:alpine  

Verify with curl:  

    curl http://127.0.0.1:8080/  

To stop and remove the container:  

    sudo nerdctl ps  
    sudo nerdctl rm -f <container-id>  

6. Bash completion  
------------------

This SlackBuild installs a completion script at /usr/share/bash-completion/completions/nerdctl.  

To use it, ensure the bash-completion package from Slackware extra is installed and sourced via /etc/profile.d/bash_completion.sh.  

Note:  
- Completions work with sudo nerdctl because completion happens before sudo executes.  
- If you log in as root directly (sudo -i or su -), you must enable bash-completion in /root/.bashrc.  

7. Conclusion  
-------------

With containerd and nerdctl, Slackware users can run containers without Docker or systemd.  
The rc.containerd script integrates with Slackware’s init system, and nerdctl provides a familiar Docker-like CLI.  
This setup is lightweight, simple, and compatible with Kubernetes tools for development and testing.  

Last Modified: 2025-08-27