OPC-UA-Adapter

Connecting OPC-UA services with the Messaging System. This component subscribes to topics from the Industrie 4.0 defacto standard protocol OPC-UA and forwards them to the messaging system which is based on Apache Kafka. Therefore both services must be running:

• one or multiple OPC-UA-server
• messaging-system

The OPC-UA Adapter is based on the components:

• Free-OPC-UA Client, python-opcua version 0.98.7
• Kafka Client librdkafka version 0.11.1
• Python Kafka module confluent-kafka-python version 0.9.1.2

Contents

1. Requirements
2. Deployment
3. Configuration
4. Trouble-Shooting

Requirements

1. Install Docker version 1.10.0+

2. Install Docker Compose version 1.6.0+

3. Clone this repository

   git clone https://github.com/iot-salzburg/dtz_opcua_adapter
   cd dtz_opcua_adapter
   git clone https://github.com/iot-salzburg/panta_rhei opcua_adapter/panta_rhei > /dev/null 2>&1 || echo "Repo already exists"
   git -C opcua_adapter/panta_rhei/ checkout client_1v0
   git -C opcua_adapter/panta_rhei/ pull

Basic Configuration

Now, the client can be imported and used in opcua-adapter/opcua-adapter.py with:

```python
import os, sys
from panta_rhei.client.digital_twin_client import DigitalTwinClient

# Set the configs, create a new Digital Twin Instance and register file structure
config = {"client_name": "opcua-adapter",
          "system": "at.srfg.iot.dtz",
          "gost_servers": "192.168.48.71:8082",
          "kafka_bootstrap_servers": "192.168.48.71:9092,192.168.48.72:9092,192.168.48.73:9092,192.168.48.74:9092,192.168.48.75:9092"}
client = DigitalTwinClient(**config)
client.register_new(instance_file=INSTANCES)
 ```

Note that the paths might be undetermined when executed locally, however using the dockerfile.yml it will work.

Quickstart

The OPC-UA-Adapter uses SensorThings to semantically augment the forwarded data. Data that is later on consumed by the suggested DB-Adapter decodes the generic data format using the same SensorThings server.

Creating the Kafka Topics

only if not already done

If zookeeper is specified by :2181, the local zookeeper service will be used. It may take some seconds until the new topics are distributed on each zookeeper instance in a cluster setup.

/kafka/bin/kafka-topics.sh --zookeeper :2181 --list
/kafka/bin/kafka-topics.sh --zookeeper :2181 --create --partitions 3 --replication-factor 3 --config min.insync.replicas=2 --config cleanup.policy=compact --config retention.ms=241920000 --topic eu.srfg.iot.dtz.data
/kafka/bin/kafka-topics.sh --zookeeper :2181 --create --partitions 3 --replication-factor 3 --config min.insync.replicas=2 --config cleanup.policy=compact --config retention.ms=241920000 --topic eu.srfg.iot.dtz.external
/kafka/bin/kafka-topics.sh --zookeeper :2181 --create --partitions 3 --replication-factor 1 --config min.insync.replicas=1 --config cleanup.policy=compact --config retention.ms=241920000 --topic eu.srfg.iot.dtz.logging
/kafka/bin/kafka-topics.sh --zookeeper :2181 --list

Testing

Configure the connection in the docker-compose.yml

services:
  adapter:
    ...
    environment:
      # Panta Rhei configuration
      CLIENT_NAME: "opcua-adapter"
      SYSTEM_NAME: "at.srfg.iot.dtz"
      SENSORTHINGS_HOST: "192.168.48.71:8082"
      BOOTSTRAP_SERVERS: "192.168.48.71:9092,192.168.48.72:9092,192.168.48.73:9092,192.168.48.74:9092,192.168.48.75:9092"

Using docker-compose: This depends on the Panta Rhei Stack and configured instance_file. Other settings are configured in the source code of opcua-adapter/opcua-adapter.py.

cd dtz_opcua-adapter
sudo docker-compose up --build -d

The flag -d stands for running it in background (detached mode):

Watch the logs with:

sudo docker-compose logs -f

Deployment in the docker swarm

Using docker stack:

If not already done, add a registry instance to register the image

sudo docker service create --name registry --publish published=5001,target=5000 registry:2
curl 127.0.0.1:5001/v2/

This should output {}:

If running with docker-compose works, the stack will start by running:

sh start-opcua-adapter.sh

Watch if everything worked fine with:

./show-adapter.sh
docker service logs -f add-opcua

Configuration

The asset structure is configured in the instance.json file to augment the incoming OPC-UA messages with metadata stored on the sensorthings server. If the structure is changed the opcua-adapter has to be restarted in order to update the structure in the SensorThings server.

Trouble-shooting

Can't apt-get update in Dockerfile:

Restart the service

sudo service docker restart

or add the file /etc/docker/daemon.json with the content:

{
    "dns": [your_dns, "8.8.8.8", "8.8.8.4"]
}

where your_dns can be found with the command:

nmcli device show [interfacename] | grep IP4.DNS

Traceback of non zero code 4 or 128:

Restart service with sudo service docker restart

or add your dns address as described above