db-connect.adoc

Database connections

Airflow requires a metadata database for storing e.g. DAG, task and Job data. The actual connection string is provided by the operator so that the user does not need to remember the exact structure. The same database can be accessed using different drivers: this is also handled by the operator, since the context is known (e.g. job metadata vs. queued job metadata) when parsing the resource file.

Typed connections

---
spec:
  clusterConfig:
    metadataDatabase:
      postgresql: # (1)
        host: airflow-postgresql
        databaseName: airflow
        credentialsSecret: postgresql-credentials # (2)

1. A reference to one of the supported database backends (e.g. postgresql).

2. A reference to a secret which must contain the two fields username and password.

The queue/broker metadata and URL is only needed when running the celery executor. The celeryResultBackend definition uses the same structure as metadataDatabase shown above. The celeryBrokerUrl definition is similar but does not require a databaseName.

---
spec:
  celeryExecutors:
    celeryResultBackend:
      postgresql: # (1)
        host: airflow-postgresql
        databaseName: airflow
        credentialsSecret: postgresql-credentials # (2)
    celeryBrokerUrl:
      redis: # (3)
        host: airflow-redis-master
        credentialsSecret: redis-credentials # (2)

1. A reference to one of the supported database backends (e.g. postgresql).

2. A reference to a secret which must contain the two fields username and password.

3. A reference to one of the supported queue brokers (e.g. redis).

Generic connections

Alternatively, these connections can also be defined in full in a referenced secret:

---
spec:
  clusterConfig:
    metadataDatabase:
      generic:
        uriSecret: postgresql-metadata # (1)

---
spec:
  celeryResultBackend:
      generic:
        uriSecret: postgresql-celery # (2)
    celeryBrokerUrl:
      generic:
        uriSecret: redis-celery # (3)

1. A reference to a secret which must contain the single fields uri e.g. uri: postgresql+psycopg2://airflow:airflow@airflow-postgresql/airflow

2. A reference to a secret which must contain the single fields uri e.g. uri: db+postgresql://airflow:airflow@airflow-postgresql/airflow

3. A reference to a secret which must contain the single fields uri e.g. uri: redis://:redis@airflow-redis-master:6379/0