# Trigger one of a set of handlers

**URL:** <https://forum.ansible.com/t/trigger-one-of-a-set-of-handlers/4177>\
**Category:** Get Help\
**Created:** [March 1, 2024, 7:34pm UTC](https://forum.ansible.com/t/trigger-one-of-a-set-of-handlers/4177 "2024-03-01T19:34:07Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![jms1](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/jms1/32/2255_2.png) [@jms1](https://forum.ansible.com/u/jms1)\
**Post date:** [March 1, 2024, 7:34pm UTC](https://forum.ansible.com/t/trigger-one-of-a-set-of-handlers/4177/1 "2024-03-01T19:34:07Z")

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I’m writing a fairly typical role to install and configure Apache.

- If the primary `httpd.conf` file is changed, I need to “restart” Apache. This ends up running the usual `service httpd restart` or `systemctl restart httpd` command.

- If an SSL key/cert file is updated, I need to “reload” Apache. This involves running `service httpd reload` or `systemctl reload httpd`, which tells the running Apache process to re-read those files from disk and start using them, without breaking any existing connections (the app involved uses websockets, which means long-lived connections, and restarting Apache causes dozens to thousands of clients to try and re-connect all at once, not happy fun times.)

Is there a way to ensure that, if both types of files are updated, ONLY the restart happens? Doing a reload immediately after starting or restarting Apache just wastes time and CPU cycles, because it will already have the “new” key/cert files in memory.

Also, is there a way to control the _sequence_ in which the handlers are executed? Is it based on the order they appear in the `handlers/main.yml` file? The order of the tasks which “trigger” each handler? Alphabetical order based on the handler’s name? Phase of the moon?

I’m thinking if I can do something like `register : apache_restarted` on the “restart” handler, I can add `when : not apache_restarted` (not sure about the syntax, but the idea should be obvious) to the “reload” handler, so that if “restart” happened, “reload” would not. (Or can you even _have_ a `when:` clause on a task which is called as a handler?)

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**Author:** ![mkrizek](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/mkrizek/32/2055_2.png) [@mkrizek](https://forum.ansible.com/u/mkrizek)\
**Post date:** [March 4, 2024, 8:02am UTC](https://forum.ansible.com/t/trigger-one-of-a-set-of-handlers/4177/2 "2024-03-04T08:02:13Z")

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> Also, is there a way to control the _sequence_ in which the handlers are executed? Is it based on the order they appear in the `handlers/main.yml` file? The order of the tasks which “trigger” each handler? Alphabetical order based on the handler’s name? Phase of the moon?

From [Handlers: running operations on change — Ansible Documentation](https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_handlers.html#notifying-handlers:)

> Handlers are executed in the order they are defined in the `handlers` section, not in the order listed in the `notify` statement.

So all handlers (including the ones from roles) are inserted into the play’s global namespace and when notified the order of execution is the order they are added into the play. See the documentation linked above for additional information.