# Notify after other host after X has happened on Y host.

**URL:** <https://forum.ansible.com/t/notify-after-other-host-after-x-has-happened-on-y-host/15148>\
**Category:** Ansible Project\
**Created:** [May 2, 2014, 7:00pm UTC](https://forum.ansible.com/t/notify-after-other-host-after-x-has-happened-on-y-host/15148 "2014-05-02T19:00:15Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![nZac](https://avatars.discourse-cdn.com/v4/letter/n/c6cbf5/32.png) [@nZac](https://forum.ansible.com/u/nZac)\
**Post date:** [May 2, 2014, 7:00pm UTC](https://forum.ansible.com/t/notify-after-other-host-after-x-has-happened-on-y-host/15148/1 "2014-05-02T19:00:15Z")

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I was reading through this reddit thread: [http://www.reddit.com/r/Python/comments/24a4r0](http://www.reddit.com/r/Python/comments/24a4r0) and found this comment: ‘I found Ansible to be fairly dreadful. It’s difficult to do simple things like “don’t start up the app server until the database schema on another machine has been updated”.’

How would this be done in Ansible? My understanding would be you could:

. Take the application node offline  
. Update the database schema  
. Update the application server  
. Put the application node online

Am I missing something? Is this situation more complex?

Thanks for your thoughts.  
NZ

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**Author:** ![Michael\_DeHaan1](https://avatars.discourse-cdn.com/v4/letter/m/5e9695/32.png) [@Michael\_DeHaan1](https://forum.ansible.com/u/Michael_DeHaan1)\
**Post date:** [May 2, 2014, 7:17pm UTC](https://forum.ansible.com/t/notify-after-other-host-after-x-has-happened-on-y-host/15148/2 "2014-05-02T19:17:31Z")

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Sounds like that person didn’t get into Ansible very far at all.

- hosts: databases  
tasks:

- 
# your update steps here
- hosts: appservers  
tasks:

- 
# all the steps here

Ordering in Ansible is intrinsic to the system and there’s nothing complicated here to do at all.

Playbooks contain an ordered list of plays, so you can just address different groups in any order you like, including revisiting previous groups.

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**Author:** ![Michael\_DeHaan1](https://avatars.discourse-cdn.com/v4/letter/m/5e9695/32.png) [@Michael\_DeHaan1](https://forum.ansible.com/u/Michael_DeHaan1)\
**Post date:** [May 2, 2014, 7:18pm UTC](https://forum.ansible.com/t/notify-after-other-host-after-x-has-happened-on-y-host/15148/3 "2014-05-02T19:18:05Z")

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Nice reply on Reddit "  
Um, that’s as hard as putting the “start app server” command after the “update schema” command.

"

🙂

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**Author:** ![nZac](https://avatars.discourse-cdn.com/v4/letter/n/c6cbf5/32.png) [@nZac](https://forum.ansible.com/u/nZac)\
**Post date:** [May 2, 2014, 7:56pm UTC](https://forum.ansible.com/t/notify-after-other-host-after-x-has-happened-on-y-host/15148/4 "2014-05-02T19:56:39Z")

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I missed the reply on Reddit, but that makes sense to me. Happy to know it is as “radically simple” as I thought it would be.