Error: pidfile (celerybeat.pid) already exists when celery starts beat

Preface

start-up celery beat There is an error Pidfile (celerybeat.pid) already exists.
Look at this error report and say yes Pidfile file ‘celerybeat.pid’ There is already

terms of settlement

Execute startup beat The service

>celery -A  Project name  beat -l info

A file will be automatically created under the root directory of the project
pidfile： The default is celerybeat.pid, Save in the project root directory .

An error is reported that it already exists , Then delete it

When the service is stopped , This file will be deleted automatically , Next time you start the service, create a new celerybeat.pid

The reason for this problem ： Maybe it's time to start the service , The service is not shut down normally , Turn it off directly , When the service is stopped , The file was not deleted