# PLCnext Technology compatible container runtimes - Docker, Moby, balenaEngine

Project details

This project and the App are discontinued!!

PLCnext Technology has a preinstalled podman and podman-compose, available as root, for testing purpose only. For productive use, podman and podman-compose will be available rootless for the admin user and for PLCnext Technology app developer starting with firmware 2025.0.

Description	Value
Created	18.02.2020
Last modified	23.10.2024
Controller	AXC F 1152; AXC F 2152; AXC F 3152
Firmware	2021.0 LTS

Changes for PLCnext firmware 2021.0 LTS

• iptables-nft is now part of the FW image
• Publish as APP in PLCnext Store
• Added docker as installation option
• Removed the version selection (only the default versions of balena and docker are stable)
• Fixed docker-dompose
• Fixed issue with the PLCnext firewall and WBM

For the difference between Docker and balenaEngine, see https://www.balena.io/engine/

Known issues:

• Factory reset does not remove application images and cache.
• server certificate verification failed due to an incorrect system time

Read the Workarounds chapter for fixes.

Introduction

The following chapters provides an introduction and first steps with Balena-Engine an IoT focused Docker like container technology on a PLCnext control.

For more Information about Balena-Engine visit the website and the GitHub project.

Install on Target

For installation you need to be root user:

To change to root:

su

To set the password from root

sudo passwd root

For installation:

# Download the Project
git clone https://github.com/PLCnext/Docker_GettingStarted.git

# Execute Setup.sh in archive
cd Docker_GettingStarted
chmod +x setup.sh
./setup.sh

Workarounds

Fully remove images and cache before/after firmware reset

Login to the terminal, change to root and remove the folder manually

rm -rf /media/rfs/rw/var/lib/balena

Set the system time

Login to the terminal and set the system clock to the correct time.

sudo date -s "YYYY-MM-DD hh:mm:ss"

More information on the topic system time can be found here in the PLCnext Info Center.

How to get support or provide suggestion and ideas

You can get support or provide suggestion and ideas in the forum of the PLCnext Community.

Work with containers

All OCI compatible images can be used in combination with balena, especially docker images.
For images see: https://hub.docker.com/

Internet connection is required!

Download an image to the controller

Pull loads an image from a repository and stores it locally. if no complete domain is given, the images on https://hub.docker.com/ are searched automatically.

root@axcf2152:~# balena-engine pull armhf/debian

Start an image on the controller

Start creates a container from an image available on the local computer

root@axcf2152:~# balena-engine start armhf/debian

Run an image

The run command combines pull and start

root@axcf2152:~# balena-engine run armhf/debian

Start an image and get access into the container

The command -it (interactive with tty) creates a new process in a container. The entry point must also be specified. In the example /bin/bash

root@axcf2152:~# balena-engine run -it debian /bin/bash
# Result: If a container is successfully started
root@9bc6dd4527e0:/#

Test the internet access inside docker container

root@9bc6dd4527e0:/# ping 8.8.8.8
# Result:
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=55 time=14.6 ms

Exit the running container

When closing and restarting containers the runtime data (data that is not part of the image) is lost. If this data is to be retained, it must be stored persistently. See volumes.

root@9bc6dd4527e0:/# exit
# Result:
root@axcf2152:~#

Working with Volumes

Mounting host volumes into the container and test it. A host volume is one way to persist data from a container.

# Create a project folder on the host e.g. /opt/plcnext/test and mount it in the container as /home/test/
root@axcf2152:~# mkdir /opt/plcnext/test
root@axcf2152:~# balena-engine run -it -v /opt/plcnext/test:/home/test/ debian bash

Alternative to host volumes, you can use container volumes on your host. There are also other methods to persistently store data from containers, for which various drivers are provided. Besides volumes and folders, central network storage, such as NFS, is often used.

# For use a container volume you need a name instead of directory. Example:
balena-engine run -it -v test:/home/test/ debian bash
# will be create a volume.

# The volumes can be viewed by:
root@axcf2152:~# balena-engine volume ls

# The content of the volume can be inspected via ls on the host system
root@axcf2152:~# ls /media/rfs/rw/var/lib/balena/volumes/test/_data

Show all OCI container

You can see an example output on the console.

root@axcf2152:~# balena-engine ps -a
Result:
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS                       PORTS                                            NAMES
4401cdaf0fee        armhf/debian          "bash"                   7 minutes ago       Exited (130) 8 seconds ago                                                    cranky_mayer
df194ad3f89d        debian                "bash"                   22 minutes ago      Exited (0) 21 minutes ago                                                     agitated_austin
092fe03508aa        nginx                 "nginx -g 'daemon of…"   33 minutes ago      Exited (0) 31 minutes ago                                                     magical_antonelli
0dd0b4d84759        registry:2            "/entrypoint.sh /etc…"   About an hour ago   Up About an hour             5000/tcp, 0.0.0.0:5000->5000/tcp                 registry_name
2c71de9f0555        portainer/portainer   "/portainer"             About an hour ago   Up About an hour             0.0.0.0:18000->8000/tcp, 0.0.0.0:19000->9000/tcp frosty_mclean

Remove container

You can see an example output on the console.

root@axcf2152:~# balena-engine rm 44 (a part of ID-Number: 4401cdaf0fee)
root@axcf2152:~# balena-engine ps -a
Result:
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS                       PORTS                                            NAMES
df194ad3f89d        debian                "bash"                   22 minutes ago      Exited (0) 21 minutes ago                                                     agitated_austin
092fe03508aa        nginx                 "nginx -g 'daemon of…"   33 minutes ago      Exited (0) 31 minutes ago                                                     magical_antonelli
0dd0b4d84759        registry:2            "/entrypoint.sh /etc…"   About an hour ago   Up About an hour             5000/tcp, 0.0.0.0:5000->5000/tcp                 registry_name
2c71de9f0555        portainer/portainer   "/portainer"             About an hour ago   Up About an hour             0.0.0.0:18000->8000/tcp, 0.0.0.0:19000->9000/tcp frosty_mclean

Examples

Examples of interesting projects.

Run a local registry

See following Usecase: https://docs.docker.com/registry/deploying/

root@axcf2152:~# balena-engine run -d -p 5000:5000 --name registry_name registry:2

Run a local webserver nginx

Find more information under: https://hub.docker.com/_/nginx

root@axcf2152:~# balena-engine run -d nginx

Deploy and start Portainer (user interface for container runtimes)

See Portainer Quick-Start: https://portainer.readthedocs.io/en/stable/deployment.html#quick-start
Result: Open Webbrowser and login into Portainer Docker-Management-Tool (http://192.168.1.10:9000/#/home)

balena-engine run -d -p 8000:8000 -p 9000:9000 -v /var/run/balena-engine.sock:/var/run/balena-engine.sock -v portainer_data_name:/data portainer/portainer

License

balenaEngine, Moby and Docker are licensed under the Apache License, Version 2.0.

Copyright (c) Phoenix Contact Gmbh & Co KG. All rights reserved.

Licensed under the MIT License.