# overview #

This directory splits up the configuration of chrony into multiple fragments so
that NTP servers can be more easily dynamically configured at an instance's
launch time without losing customizations at a global level.

Files found under the /etc/chrony.d directory with the ".conf" extension are
parsed in the lexicographical order of the file names when chronyd starts up.

Files in this directory or in /run/chrony.d that end with the ".sources"
extension can only contain the "peer", "pool" and "server" directives and must
have all lines terminated by a trailing newline. There is no need to restart
chronyd for these time sources to be usable, running '# chronyc reload sources'
is sufficient.

# configuration #

chrony on Amazon Linux defaults to using Amazon Time Sync time sources via both
link-local and remote endpoints.

There are several mechanisms by which you may override the default configuration
if needed:

1. You can switch to the pool.ntp.org time server pool by setting
   USE_AMAZON_NTP_ENDPOINTS=no in /etc/sysconfig/chrony and invoking the
   chrony-config service (systemctl restart chrony-config.service).

2. You can provide a custom list of time sources via DHCP by creating a new DHCP
   Option Set and associating it with your VPC.  See
   https://docs.aws.amazon.com/vpc/latest/userguide/VPC_DHCP_Options.html for
   details.

3. You can configure cloud-init's NTP module with various chrony configuration
   parameters and sources per
   https://cloudinit.readthedocs.io/en/22.2.2/topics/modules.html#ntp