airflow db init 报错

报错一：

[2022-08-01 11:34:38,224] {manager.py:763} WARNING - No user yet created, use flask fab command to do it.
INFO  [alembic.runtime.migration] Running upgrade a13f7613ad25 -> 97cdd93827b8, Add queued_at column to dagrun table
INFO  [alembic.runtime.migration] Running upgrade 97cdd93827b8 -> 092435bf5d12, Add max_active_runs column to dagmodel table
INFO  [alembic.runtime.migration] Running upgrade 092435bf5d12 -> ccde3e26fe78, Add index on state, dag_id for queued dagrun
INFO  [alembic.runtime.migration] Running upgrade ccde3e26fe78 -> 83f031fd9f1c, improve mssql compatibility
INFO  [alembic.runtime.migration] Running upgrade 83f031fd9f1c -> e9304a3141f0, make xcom pkey columns non-nullable
INFO  [alembic.runtime.migration] Running upgrade e9304a3141f0 -> 30867afad44a, Rename concurrency column in dag table to max_active_tasks
INFO  [alembic.runtime.migration] Running upgrade 30867afad44a -> 54bebd308c5f, Add trigger table and task info
INFO  [alembic.runtime.migration] Running upgrade 54bebd308c5f -> 142555e44c17, Add data_interval_[start|end] to DagModel and DagRun.
INFO  [alembic.runtime.migration] Running upgrade 142555e44c17 -> 7b2661a43ba3, TaskInstance keyed to DagRun
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/airflow/models/crypto.py", line 86, in get_fernet
    [Fernet(fernet_part.encode('utf-8')) for fernet_part in fernet_key.split(',')]
  File "/usr/local/lib/python3.6/site-packages/airflow/models/crypto.py", line 86, in <listcomp>
    [Fernet(fernet_part.encode('utf-8')) for fernet_part in fernet_key.split(',')]
  File "/usr/local/lib64/python3.6/site-packages/cryptography/fernet.py", line 35, in __init__
    "Fernet key must be 32 url-safe base64-encoded bytes."
ValueError: Fernet key must be 32 url-safe base64-encoded bytes.

报错二：

File "/usr/local/lib/python3.6/site-packages/airflow/utils/db.py", line 112, in create_default_connections
  extra='''{"account_url": "<ACCOUNT_URL>"}''',
File "<string>", line 4, in __init__
File "/usr/local/lib64/python3.6/site-packages/sqlalchemy/orm/state.py", line 433, in _initialize_instance
  manager.dispatch.init_failure(self, args, kwargs)
File "/usr/local/lib64/python3.6/site-packages/sqlalchemy/util/langhelpers.py", line 70, in __exit__
  with_traceback=exc_tb,
File "/usr/local/lib64/python3.6/site-packages/sqlalchemy/util/compat.py", line 182, in raise_
  raise exception
File "/usr/local/lib64/python3.6/site-packages/sqlalchemy/orm/state.py", line 430, in _initialize_instance
  return manager.original_init(*mixed[1:], **kwargs)
File "/usr/local/lib/python3.6/site-packages/airflow/models/connection.py", line 146, in __init__
  self.extra = extra
File "<string>", line 1, in __set__
File "/usr/local/lib/python3.6/site-packages/airflow/models/connection.py", line 272, in set_extra
  fernet = get_fernet()
File "/usr/local/lib/python3.6/site-packages/airflow/models/crypto.py", line 90, in get_fernet
  raise AirflowException(f"Could not create Fernet object: {value_error}")
airflow.exceptions.AirflowException: Could not create Fernet object: Incorrect padding

原因是airflow.cfg缺少了fernet_key没填写导致
# Secret key to save connection passwords in the db
fernet_key = 

具体操作如下：
1 把airflow的数据库表清空

2 生成一个fernet_key，用于airflow db init阶段使用（确保有cryptography的包）
python3 -c "from cryptography.fernet import Fernet; print(Fernet.generate_key().decode())"

3 填入上面生成的key，保存
fernet_key = xxxxx

4 重新运行airflow db init,报错解决