This commit addresses multiple bugs in systemd service files reported
in issue #53706:

1. Fix incorrect command in airflow-api.service

   • Changed 'airflow api' to 'airflow api-server' (correct CLI command)

2. Standardize environment configuration approach

   • Changed airflow-api.service and airflow-triggerer.service to use
     EnvironmentFile=/etc/sysconfig/airflow instead of inline Environment
   • This provides consistency with other services and allows admins
     flexibility to manage custom environment variables centrally

3. Fix service dependencies

   • Added proper After= and Wants= clauses for database and message
     queue services (postgresql, mysql, redis, rabbitmq) to
     airflow-api.service and airflow-triggerer.service
   • Services now wait for required dependencies before starting

4. Additional bug fixes discovered during review

   • airflow-flower.service: Removed duplicate ExecStart line
   • airflow-kerberos.service: Fixed command from 'kerberos' to
     'airflow kerberos'

5. Consistency improvements

   • Added Type=simple and RestartSec=5s to airflow-api.service and
     airflow-triggerer.service for consistency with other services

All systemd service files now follow the same configuration pattern,
making them easier to maintain and more reliable during system startup.

Fixes #53706
(cherry picked from commit b370160)

Co-authored-by: Ashir Alam alamashir@gmail.com