Hashicorp Vault Secrets Backend

To enable Hashicorp vault to retrieve Airflow connection/variable, specify VaultBackend as the backend in [secrets] section of airflow.cfg.

Here is a sample configuration:

[secrets]
backend = airflow.providers.hashicorp.secrets.vault.VaultBackend
backend_kwargs = {"connections_path": "connections", "variables_path": "variables", "mount_point": "airflow", "url": "http://127.0.0.1:8200"}

The default KV version engine is 2, pass kv_engine_version: 1 in backend_kwargs if you use KV Secrets Engine Version 1.

You can also set and pass values to Vault client by setting environment variables. All the environment variables listed at https://www.vaultproject.io/docs/commands/#environment-variables are supported.

Hence, if you set VAULT_ADDR environment variable like below, you do not need to pass url key to backend_kwargs:

export VAULT_ADDR="http://127.0.0.1:8200"

Set up a Vault mount point

You can make a mount_point for airflow as follows:

vault secrets enable -path=airflow -version=2 kv

Optional lookup

Optionally connections, variables, or config may be looked up exclusive of each other or in any combination. This will prevent requests being sent to Vault for the excluded type.

If you want to look up some and not others in Vault you may do so by setting the relevant *_path parameter of the ones to be excluded as null.

For example, if you want to set parameter connections_path to "airflow-connections" and not look up variables, your configuration file should look like this:

[secrets]
backend = airflow.providers.hashicorp.secrets.vault.VaultBackend
backend_kwargs = {"connections_path": "airflow-connections", "variables_path": null, "mount_point": "airflow", "url": "http://127.0.0.1:8200"}

Storing and Retrieving Connections using connection URI representation

If you have set connections_path as connections and mount_point as airflow, then for a connection id of smtp_default, you would want to store your secret as:

vault kv put airflow/connections/smtp_default conn_uri=smtps://user:host@relay.example.com:465

Note that the Key is conn_uri, Value is postgresql://airflow:airflow@host:5432/airflow and mount_point is airflow.

Verify that you can get the secret from vault:

❯ vault kv get airflow/connections/smtp_default
====== Metadata ======
Key              Value
---              -----
created_time     2020-03-19T19:17:51.281721Z
deletion_time    n/a
destroyed        false
version          1

====== Data ======
Key         Value
---         -----
conn_uri    smtps://user:host@relay.example.com:465

The value of the Vault key must be the connection URI representation of the connection object to get connection.

Storing and Retrieving Connections using Connection class representation

If you have set connections_path as connections and mount_point as airflow, then for a connection id of smtp_default, you would want to store your secret as:

vault kv put airflow/connections/smtp_default conn_type=smtps login=user password=host host=relay.example.com port=465

Note that the Keys are parameters of the Connection class and the Value their argument.

Verify that you can get the secret from vault:

❯ vault kv get airflow/connections/smtp_default
====== Metadata ======
Key              Value
---              -----
created_time     2020-03-19T19:17:51.281721Z
deletion_time    n/a
destroyed        false
version          1

====== Data ======
Key         Value
---         -----
conn_type   smtps
login       user
password    host
host        relay.example.com
port        465

Storing and Retrieving Variables

If you have set variables_path as variables and mount_point as airflow, then for a variable with hello as key, you would want to store your secret as:

vault kv put airflow/variables/hello value=world

Verify that you can get the secret from vault:

❯ vault kv get airflow/variables/hello
====== Metadata ======
Key              Value
---              -----
created_time     2020-03-28T02:10:54.301784Z
deletion_time    n/a
destroyed        false
version          1

==== Data ====
Key      Value
---      -----
value    world

Note that the secret Key is value, and secret Value is world and mount_point is airflow.

Storing and Retrieving Config

If you have set config_path as config and mount_point as airflow, then for config sql_alchemy_conn_secret with sql_alchemy_conn_value as value, you would want to store your secret as:

vault kv put airflow/config/sql_alchemy_conn_value value=postgres://user:pass@host:5432/db?ssl_mode=disable

Verify that you can get the secret from vault:

❯ vault kv get airflow/config/sql_alchemy_conn_value
====== Metadata ======
Key              Value
---              -----
created_time     2020-03-28T02:10:54.301784Z
deletion_time    n/a
destroyed        false
version          1

==== Data ====
Key      Value
---      -----
value    postgres://user:pass@host:5432/db?ssl_mode=disable

Then you can use above secret for sql_alchemy_conn_secret in your configuration file.

[core]
 sql_alchemy_conn_secret: "sql_alchemy_conn_value"

Note that the secret Key is value, and secret Value is postgres://user:pass@host:5432/db?ssl_mode=disable and mount_point is airflow.

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