Wrong service name used for chrony when restarting service

Bug Description

service is called chronyd and not chrony in CentOS/RH. Have been tested with lated CentOS cloud image + all latest updates (with epel enabled).

[root@myhostname ~]# uname -a
Linux myhostname 3.10.0-1127.13.1.el7.x86_64 #1 SMP Tue Jun 23 15:46:38 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
[root@myhostname ~]# cat /etc/centos-release
CentOS Linux release 7.8.2003 (Core)

[root@myhostname ~]# cloud-init single --name cc_ntp
Cloud-init v. 18.5 running 'single' at 2020年7月01日 19:16:33 +0000. Up 54.51 seconds.
2020年07月01日 19:16:34,023 - cc_ntp.py[ERROR]: Failed to reload/start ntp service: Unexpected error while running command.
Command: ['systemctl', 'reload-or-restart', 'chrony']
Exit code: 5
Reason: -
Stdout:
Stderr: Failed to reload-or-restart chrony.service: Unit not found.
Traceback (most recent call last):
File "/usr/lib/python2.7/site-packages/cloudinit/config/cc_ntp.py", line 547, in handle
systemd=cloud.distro.uses_systemd())
File "/usr/lib/python2.7/site-packages/cloudinit/config/cc_ntp.py", line 436, in reload_ntp
util.subp(cmd, capture=True)
File "/usr/lib/python2.7/site-packages/cloudinit/util.py", line 2084, in subp
cmd=args)
ProcessExecutionError: Unexpected error while running command.
Command: ['systemctl', 'reload-or-restart', 'chrony']
Exit code: 5
Reason: -
Stdout:
Stderr: Failed to reload-or-restart chrony.service: Unit not found.
2020年07月01日 19:16:34,025 - util.py[WARNING]: Running module cc_ntp (<module 'cloudinit.config.cc_ntp' from '/usr/lib/python2.7/site-packages/cloudinit/config/cc_ntp.pyc'>) failed
2020年07月01日 19:16:34,040 - main.py[WARNING]: Ran cc_ntp but it failed!

Centos/Rhel/Fedora/SuSE all use chronyd.service.

It also turns out there's no templates/chrony.conf.centos.tmpl (or ntp); we can reuse the rhel one though.

This bug is believed to be fixed in cloud-init in version 22.3. If this is still a problem for you, please make a comment and set the state back to New

Thank you.

Tracked in Github Issues as https://github.com/canonical/cloud-init/issues/3756

Also affects Rocky Linux