Does Ansible delegate_to work with handlers? - ansible

Question

I wrote a playbook to modify the IP address of several remote systems. I wrote the playbook to change only a few systems at a time, so I wanted to use delegate_to to change the DNS record on the nameservers as each system was modified, instead of adding a separate play targeted at the nameservers that would change all the host IPs at once.
However, it seems the handler is being run on the primary playbook target, not my delegate_to target. Does anyone have recommendations for working around this?
Here's my playbook:
---
host: hosts-to-modify
serial: 1
tasks:
- Modify IP for host-to-modify
//snip//
- name: Modify DNS entry
delegate_to: dns-servers
become: yes
replace:
args:
backup: yes
regexp: '^{{ inventory_hostname }}\s+IN\s+A\s+[\d\.]+$'
replace: "{{ inventory_hostname }} IN A {{ new_ip }}"
dest: /etc/bind/db.my.domain
notify:
- reload dns service
handlers:
- name: reload dns service
become: yes
service:
args:
name: bind9
state: reloaded
With an inventory file like the following:
[dns-servers]
ns01
ns02
[hosts-to-modify]
host1 new_ip=10.1.1.10
host2 new_ip=10.1.1.11
host3 new_ip=10.1.1.12
host4 new_ip=10.1.1.13
Output snippet, including error message:
TASK [Modify DNS entry] ********************************************************
Friday 02 September 2016 14:46:09 -0400 (0:00:00.282) 0:00:35.876 ******
changed: [host1 -> ns01]
changed: [host1 -> ns02]
RUNNING HANDLER [reload dns service] *******************************************
Friday 02 September 2016 14:47:00 -0400 (0:00:38.925) 0:01:27.385 ******
fatal: [host1]: FAILED! => {"changed": false, "failed": true, "msg": "no service or tool found for: bind9"}

Answer 1

First of all, you example playbook is invalid in several ways: play syntax is flawed and delegate_to can't be targeted to a group of hosts.
If you want to delegate to multiple servers, you should iterate over them.
And answering your main question: yes, you can use delegate_to with handlers:
handlers:
- name: reload dns service
become: yes
service:
args:
name: bind9
state: reloaded
delegate_to: "{{ item }}"
with_items: "{{ groups['dns-servers'] }}