This article describes the procedure to automatically start mosquitto’s MQTT Broker when powering on the PLCNEXT AXCF 2152 (Firmware 2023.0).

Let’s Start!

Before Start..

At first I will try to build it according to the official podman documentation…

https://podman.io/blogs/2018/09/13/systemd.html

sudo systemctl enable redis.service
sudo systemctl start redis.service

systemctrlコマンドがないとPLCNEXTに怒られました。

An Error from PLCNEXT that feedback to me for not having the systemctrl command.

root@axcf2152:/opt/plcnext/# systemctl
sh: systemctl: command not found

MR Martrin said systemctrl is not supported by PLCNEXT.

https://www.plcnext-community.net/forum/#/discussion/1184/controlling-the-openvpn-service

Start From Example

But there are still plenty of ways to do it. This time, we will modify the init.d File so that podman can be started automatically.You can download the Example from this link.

https://github.com/plcnextusa/init.d_Example

Be careful!

Operate carefully. If you delete the wrong File or Folder, PLCNEXT will not be able to start.

Clone the Example

Download>Unzip the File from the previous Link and transfer all the File to PLCNEXT via SFTP Software such as WinSCP.

git clone https://github.com/plcnextusa/init.d_Example.git

Installation

The destination is /opt/plcnext/.

Login as Root

Please login as root with SSH Client.

Change the permission

Edit permissions so that all Downloaded Files can be executed.

root@axcf2152:chmod +x install.sh python.sh helloworld.py

Execute the Shell Script

Just run install.sh.

root@axcf2152:./install.sh

Check the Log Files

In the Example, Python Script automatically runs when the CPU is started up and writes text to hello.log once in every 10 seconds.

root@axcf2152:/opt/plcnext/# ls logs/
Output.log default.sqlite plcnextapp.log uatrace.log uatrace_2.log uatrace_4.log watchdogDaemon
Output.log.lock hello.log security.sqlite uatrace_1.log uatrace_3.log uatrace_5.log

Open hello.log to check it out.

root@axcf2152:cat /opt/plcnext/logs/hello.log

root@axcf2152:/opt/plcnext/# cat logs/hello.log
[2023-04-18T21:49:22] INFO [root.<module>:16] Hello from init.d!
[2023-04-18T21:49:32] INFO [root.<module>:16] Hello from init.d!
[2023-04-18T21:49:42] INFO [root.<module>:16] Hello from init.d!
[2023-04-18T21:49:52] INFO [root.<module>:16] Hello from init.d!
[2023-04-18T21:50:02] INFO [root.<module>:16] Hello from init.d!

Auto Start Mqtt Podman

Once the basic operation is confirmed, the next step is to configure the MQTT Broker to start automatically.

Broker images

First, build a Broker Container.

structure

Here is the Folder structure.

├── docker-compose.yml
├── mosquitto
└── config
└── mosquitto.conf

docker-compose.yml

Here is the Context of the Docker File.

version: “3”
services:
mqtt:
image: eclipse-mosquitto
container_name: mqtt
expose:
– 1883
ports:
– 1883:1883
restart: unless-stopped
volumes:
– ./mosquitto/config:/mosquitto/config

mosquitto.conf

This will be the MQTT Broker Configuration File.

set_tcp_nodelay true
listener 1883
allow_anonymous true
max_queued_messages 0

change rights

Edit permissions so that all Files can be executed before Building Container.

chmod +x

build

Build the images.

docker-compose up

startup.sh

The Shell Script contains commands to start the MQTT Container, etc.

#!/bin/sh
echo “Hello start” >> /opt/plcnext/log.txtpodman network create podmanpodman start mqttpodman start mqttpodman start mqttpodman start mynoderedecho “end…” >> /opt/plcnext/log.txt

Update the python.sh

Now we need to edit the python.sh.

Change DAEMON=$DIR/startup.sh and set starup.sh as the file to run.

Change DAEMON_USER=root to set the User to run as root.

#!/bin/sh

### BEGIN INIT INFO
# Provides: myservice
# Required-Start: $remote_fs $syslog
# Required-Stop: $remote_fs $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Put a short description of the service here
# Description: Put a long description of the service here
### END INIT INFO

# Change the next 3 lines to suit where you install your script and what you want to call it
DIR=/opt/plcnext
DAEMON=$DIR/startup.sh
DAEMON_NAME=hello2

# Change the uuser that runs the script if accessing files. Otherwise keep as admin.
DAEMON_USER=root

# The process ID of the script when it runs is stored here:
PIDFILE=/var/run/$DAEMON_NAME.pid

do_start () {
# Starts the daemon (our python script) in the background with the configured DAEMON_USER
start-stop-daemon –start –background –pidfile $PIDFILE –make-pidfile –user $DAEMON_USER –chuid $DAEMON_USER –startas $DAEMON — $DAEMON_OPTS
}
do_stop () {
# Starts the daemon (our python script) based to the process id, after 10 retries it just kills the process
start-stop-daemon –stop –pidfile $PIDFILE –retry 10
}

#keys to call the script, e.g. ./pystart.sh start
case “$1” in

start|stop)
do_${1}
;;

restart|reload|force-reload)
do_stop
do_start
;;

*)
echo “Usage: /etc/init.d/$DAEMON_NAME {start|stop|restart}”
exit 1
;;

esac
exit 0

Updating your init.d service

If you change Scripts, etc. again in the future, and do not want to restart the CPU, you can restart only Services with the following command.

/etc/init.d/python.sh restart

Check MQTT Docker

Done! After restarting, the MQTT Broker started automatically.

root@axcf2152:/opt/plcnext/# podman ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
34fa7e1faf20 docker.io/library/eclipse-mosquitto:latest /usr/sbin/mosquit… 17 hours ago Up 18 minutes ago 0.0.0.0:1883->1883/tcp mqtt

Uninstalling the example

To remove the Example File you have just installed, execute the following command.

update-rc.d –f python.sh remove
rm -r python.sh

Be careful!

Before deleting Services in the init.d of PLCNEXT, be careful to check where you are deleting them. If you delete the wrong services file, PLCNEXT will not be able to start.

What is inide?

Finally, Here is a brief description of the contents of Install.sh.

Install.sh

#!/bin/bash

echo “Starting install process…. Please wait…”

echo “Changing permissions for execution”
chmod +x /opt/plcnext/helloworld.py
chmod +x /opt/plcnext/python.sh

echo “Setting up init.d”
cp –a /opt/plcnext/python.sh /etc/init.d/
cd /etc/init.d/
update-rc.d python.sh defaults
./python.sh start
rm -r /opt/plcnext/python.sh

echo “Removing residual files”
cd /opt/plcnext/
rm -r README.md
rm -r install.sh

echo “Log file for errors is hello.log in the /opt/plcnext/logs folder.”
echo “Install complete!”

“#! /bin/bash” is a special comment written on the first line of a shell script to indicate which program the shell should use to execute the script. In this case, it instructs the shell to use the Bash shell to execute the script.

#!/bin/bash

Modify File’s execute permissions to allow execution.

chmod +x /opt/plcnext/helloworld.py
chmod +x /opt/plcnext/python.sh

Move File to /etc/init.d/ and change the working Directoy to /etc/init.d/.

cp –a /opt/plcnext/python.sh /etc/init.d/
cd /etc/init.d/

update-rc.d” is a management tool for init scripts used in Linux distributions such as Debian and Ubuntu. init scripts are programs that run automatically when the Linux system boots and are used to start or stop specific services running for each runlevel.

In the following Example, System will register the python.sh init script at the run level and create a symbolic link to automatically start python.sh when the system boots.

update-rc.d python.sh defaults
./python.sh start
rm -r /opt/plcnext/python.sh

最後は作業Directoryを/opt/plcnext/に戻り、不要なFileを削除する。

cd /opt/plcnext/
rm -r README.md
rm -r install.sh

python.sh

Here is the python.sh.

#!/bin/sh

### BEGIN INIT INFO
# Provides: myservice
# Required-Start: $remote_fs $syslog
# Required-Stop: $remote_fs $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Put a short description of the service here
# Description: Put a long description of the service here
### END INIT INFO

# Change the next 3 lines to suit where you install your script and what you want to call it
DIR=/opt/plcnext
DAEMON=$DIR/helloworld.py
DAEMON_NAME=hello

# Change the uuser that runs the script if accessing files. Otherwise keep as admin.
DAEMON_USER=admin

# The process ID of the script when it runs is stored here:
PIDFILE=/var/run/$DAEMON_NAME.pid

do_start () {
# Starts the daemon (our python script) in the background with the configured DAEMON_USER
start-stop-daemon –start –background –pidfile $PIDFILE –make-pidfile –user $DAEMON_USER –chuid $DAEMON_USER –startas $DAEMON — $DAEMON_OPTS
}
do_stop () {
# Starts the daemon (our python script) based to the process id, after 10 retries it just kills the process
start-stop-daemon –stop –pidfile $PIDFILE –retry 10
}

#keys to call the script, e.g. ./pystart.sh start
case “$1” in

start|stop)
do_${1}
;;

restart|reload|force-reload)
do_stop
do_start
;;

*)
echo “Usage: /etc/init.d/$DAEMON_NAME {start|stop|restart}”
exit 1
;;

esac
exit 0

Set the User to execute this file.

DAEMON_USER=admin

Configure the PIDFILE.

PIDFILE=/var/run/$DAEMON_NAME.pid

start-stop-daemon” is a tool to start, stop, and restart daemon processes on Unix-based operating systems. Daemon processes are resident processes that run in the background and are responsible for various tasks such as system administration and service provision.

–start: Specifies that the daemon process is to be started.
-b, –background: Specifies that the daemon process should run in the background.
-m, –make-pidfile: Specifies that a process ID file is to be created.
-p, –pidfile PIDFILE: Specifies the location of the process ID file.
-c, –chuid USER:GROUP: Specifies the user and group to run the daemon process.
-d, –chdir DIR: Specifies the directory where the daemon process will run.
-e, –exec EXEC: Specifies an executable file to start the daemon process.
-u, –user USER: Specifies the user to run the daemon process.
-g, –group GROUP: Specifies a group to run the daemon process.
-s, –signal SIGNAL: Specifies a signal to send to the daemon process.
-k, –stop: Specifies that the daemon process should be stopped.
-n, –name NAME: Specifies the name of the daemon process.
-R, –retry RETRY: Specifies the number of retries.
–oknodo: Assume success without doing anything if the process is already running.
–startas STARTAS: Specifies the name of the new process.
–test: Display debugging information without executing commands.
–version: Display version information.

These options can be combined to start, stop, restart, and control the daemon process.

start–stop–daemon —start —background —pidfile $PIDFILE —make–pidfile —user $DAEMON_USER —chuid $DAEMON_USER —startas $DAEMON — $DAEMON_OPTS

startup.sh

Simply describe the command to be executed.

#!/bin/sh
echo “Hello start” >> /opt/plcnext/log.txtpodman network create podmanpodman start mqttpodman start mqttpodman start mqttpodman start mynoderedecho “end…” >> /opt/plcnext/log.txt