debug.md

Debug Guide

General Guidelines

• Always make sure the ENV variables are set
• Start the processes in this order - Kafka -> Eventsim -> Spark Streaming -> Airflow
• Monitor the CPU utilization for your VMs to see if something's wrong

Kafka

• Sometimes the broker & schema-registry containers die during startup, so the control center might not be available over 9021. You should just stop all the containers with docker-compose down or ctrl+C and then rerun docker-compose up.
• Did not set the KAFKA_ADDRESS env var. Kafka will then write to localhost, which will not allow Spark to read messages.

Eventsim

• If you start with a high number of users - 2-3 Million+, then eventsim sometimes might not startup and get stuck at generating events. Lower the number of users. Start two parallel processes with users divided.

Spark

• Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available.

  Make sure that the KAFKA_ADDRESS env variable is set with the external IP Address of the Kafka VM. If it's set and things still don't seem to work, restart the cluster :/.

Airflow

• Permission denied to dbt for writing logs
  • The airflow_startup.sh handles changing permission for the dbt folder, so you should be good. In case you happen to delete and recreate the folder, or not run the airflow_startup.sh script in the first place, then change the dbt folder permissions manually -

    sudo chmod -R 777 dbt/