Ansible - Handler not found on first attempt

Command run: sudo ansible-playbook site.yml --connection=local

Distributor ID: Ubuntu
Description: Ubuntu 18.04 LTS
Release: 18.04
Codename: bionic

ansible 2.5.5

I'm encountering this error only on my first run through after I change the following variable in the following file:

./group_vars/all

ntpserver: pool.ntp.org

TASK [common : Configure NTP file]
ERROR! The requested handler 'restart ntp' was not found in either the main handlers list nor in the listening handlers list


On my second run through, I'm having no issues:

TASK [common : Configure NTP file]
ok: [127.0.0.1] => {"changed": false, "checksum": "cc9e1a2d8777588fa4675e52f7ca7e352b23188a", "dest": "/etc/ntp.conf", "gid": 0, "group": "root", "mode": "0644", "owner": "root", "path": "/etc/ntp.conf", "size": 139, "state": "file", "uid": 0}

The folder and file structure I'm using is as follows:

https://github.com/ansible/ansible-examples/tree/master/lamp_simple_rhel7

./roles/common/handlers

• name: Restart NTP

service: name=ntpd state=restarted`

./roles/common/tasks

---

• name: Install NTP

apt: name=ntp state=present
tags: ntp

• name: Configure NTP file

template: src=ntp.conf.j2 dest=/etc/ntp.conf
tags: ntp
notify: restart ntp

• name: Install common packages

apt: name={{ item }} state=present
with_items:
- fail2ban
- ranger

• name: Start the NTP service

service: name=ntp state=started enabled=yes
tags: ntp

• name: Upgrade all packages to the latest version

become: true
apt:
upgrade: yes
update_cache: yes
cache_valid_time: 86400 # one-day

The name of the handler "Restart NTP" does not match the handler notified "restart ntp". This is the reason of the error.

On the second run the configuration file /etc/ntp.conf did not change ("changed": false). Therefor the handler was not notified, was not looked for, and no error was reported.

StackExchange DevOps Q#4365, answer score: 5