IoT For SAP CDK Solution

This solution was written by Kenny Rajan, Patrick Leung, Scott Francis, Will Charlton & Ganesh Suryanarayan for the Predictive Maintenance using SAP and AWS IoT to reduce operational cost blog post.

The purpose of this project is to deploy AWS cdk stacks that provide an end-to-end solution for creating SAP ticket alerts by monitoring device telemetry.

AWS Resources created in this project include:


IoT Thing	IoT Events	IAM Policies	IoT Rules
IoT Analytics	IAM Roles	IoT Policy	IoT Certificate
DynamoDB Tables	Lambdas	SNS	Secrets Manager

Other items include:


X509 Private Key	X509 Certificate Signing Request (CSR)

NOTE:

If you are using a device or other simulator with its own private key, place the CSR in the certs/ directory with:
- The filename <thing_name>.csr.pem
- The X509 Certificate Subject's CommonName is the <thing_name>
- e.g. certs/my_device_1.csr.pem == /CN=my_device_1
If you do not have a private key and CSR you want to use, they will be created for you on when the stack is deployed.

Once the iot stack is deployed the device X509 Certificate will be located in certs/<thing_name>.cert.pem.

Prerequisites

Tool	Link
AWS CDK v2	https://docs.aws.amazon.com/cdk/latest/guide/getting_started.html
`python3`	https://www.python.org/downloads/

Set Up Local Environment

git clone https://github.com/aws-samples/aws-iot-sap-condition-monitoring-demo.git
cd aws-iot-sap-condition-monitoring-demo
cd cdk-iot-analytics
python3 -m venv .venv
source .venv/bin/activate
mkdir certs
pip install -r requirements.txt

Define Variables

Configure stack variables in cdk.json:

Variable	Description
`thing_name`	The AWS IoT Thing name
`Type`	A setting specific to the SAP customer
`Equipment`	A setting specific to the SAP customer
`FunctLoc`	A setting specific to the SAP customer
`temperature_min`	Value used for determining Alarm condition
`temperature_max`	Value used for determining Alarm condition
`sns_alert_email_topic`	The SNS topic name used for sending alarm emails
`alarm_emails`	A list of email addresses to send alarm emails
`odpEntitySetName`	An Open Data Protocol setting
`odpServiceName`	An Open Data Protocol setting
`sapHostName`	The hostname or IP of the SAP server
`sapPort`	The port or IP of the SAP server
`sapUsername`	The SAP server username
`sapPassword`	The SAP server password
`urlPrefix`	Either http:// or https://

Deploy the IoT Stack

NOTE: You might need to update your CDK before deployment:

npm install -g aws-cdk@latest --force

NOTE: Bootstrapping CDK to the target account/region may be necessary:

cdk bootstrap aws://<account>/<region>

Deploy initial stack

cdk deploy iot -O=iot-outputs.json

IMPORTANT: The CloudFormation outputs must be saved to iot-outputs.json in order for the device simulator to work (see below).

Deploy the SAP Stack

For technical and legal reasons, we do not package some dependencies in this repository, so they must be packaged before deploying the SAP stack. Do this with the command, below:

pip install \
    requests \
    xmltodict \
    -t ./cdk_sap_blog/sap/lambda_assets/layer/python/

Once requests and xmltodict are packaged for the lambda layer, the stack can be deployed with the command, below:

cdk deploy sap

IMPORTANT: You should recieve a subscription notification to the emails in cdk.json/alarm_emails). Make sure you Confirm the subscription.

Deploy the Analytics Stack

cdk deploy analytics -O=analytics-outputs.json

Update Detector Model to latest version

AWSACCOUNTID=$(aws sts get-caller-identity --query Account --output text)
sed -i 's/AWSACCOUNTID/'$AWSACCOUNTID'/g' cdk_sap_blog/analytics/detector_model.json
aws iotevents update-detector-model --cli-input-json file://cdk_sap_blog/analytics/detector_model.json

Test Alarm

Test Configuration Variables

The simulator uses the temperature_min/temperature_max variables you defined in cdk.json to report temperatures uniformly to be a few degrees hotter than the maximum (see simulator.py:L50).

An alarm should be triggered shortly after starting the simulator.

Runing The Simulator

The AWS_REGION is needs to be set to the same AWS Region used to bootstrap CDK (above).

python simulator.py --region=<AWS_REGION>
python simulator.py --region=<AWS_REGION> --overtemp
python simulator.py --region=<AWS_REGION> --undertemp

Once the Alarm is triggered, the end-to-end solution has completed.

NOTE: See python simulator.py --help for more options.

Cleanup

The destroy operation (below) will fail unless we first remove (or save somewhere else) the objects in the S3 bucket we used to store the IoT Analytics data. Get the name of the bucket from the analytics-outputs.json file we created in the deploy operation.

aws s3 rm <analytics.AnalyticsBucketURI> --recursive

Then feel free to take down the 3 stacks.

cdk destroy --all

NOTE 1: Sometimes the destroy command (above) needs to be run twice. NOTE 2: Once everything is destroyed, make sure to delete the keys and certs in the certs/ directory before re-deploying.

APPENDIX

Diagram

Architecture diagram was designed with PlantUML and AWS Icons for PlantUML. Once your system is configured, run the following command to generate the diagram:

java -jar plantuml.jar iot-for-sap-architecture.puml

NOTE: If you don't know the path to your plantuml.jar file, find it with find / -name plantuml.jar 2>/dev/null.

The diagram will be saved as iot-for-sap-architecture.png.