Chapter 21. Configuring time synchronization by using the timesync RHEL System Role With the timesync RHEL System Role, you can manage time synchronization on multiple target machines on RHEL using Red Hat Ansible Automation Platform. 21.1. The timesync RHEL System Role You can manage time synchronization on multiple target machines using the timesync RHEL System Role. The timesync role installs and configures an NTP or PTP implementation to operate as an NTP client or PTP replica in order to synchronize the system clock with NTP servers or grandmasters in PTP domains. Note that using the timesync role also facilitates the migration to chrony , because you can use the same playbook on all versions of Red Hat Enterprise Linux starting with RHEL 6 regardless of whether the system uses ntp or chrony to implement the NTP protocol. 21.2. Applying the timesync System Role for a single pool of servers The following example shows how to apply the timesync role in a situation with just one pool of servers. Warning The timesync role replaces the configuration of the given or detected provider service on the managed host. settings are lost, even if they are not specified in the role variables. The only preserved setting is the choice of provider if the timesync_ntp_provider variable is not defined. Prerequisites The Ansible Core package is installed on the control machine. You have the rhel-system-roles package installed on the system from which you want to run the playbook. You have an inventory file which lists the systems on which you want to deploy timesync System Role. Procedure Create a new playbook.yml file with the following content: --- - hosts: timesync-test vars: timesync_ntp_servers: - hostname: 2.rhel.pool.ntp.org pool: yes iburst: yes roles: - rhel-system-roles.timesync Optional: Verify playbook syntax. Run the playbook on your inventory file: 21.3. Applying the timesync System Role on client servers You can use the timesync role to enable Network Time Security (NTS) on NTP clients. Network Time Security (NTS) is an authentication mechanism specified for Network Time Protocol (NTP). It verifies that NTP packets exchanged between the server and client are not altered. Warning The timesync role replaces the configuration of the given or detected provider service on the managed host. settings are lost even if they are not specified in the role variables. The only preserved setting is the choice of provider if the timesync_ntp_provider variable is not defined. Prerequisites You do not have to have Red Hat Ansible Automation Platform installed on the systems on which you want to deploy the timesync solution. You have the rhel-system-roles package installed on the system from which you want to run the playbook. You have an inventory file which lists the systems on which you want to deploy the timesync System Role. The chrony NTP provider version is 4.0 or later. Procedure Create a playbook.yml file with the following content: --- - hosts: timesync-test vars: timesync_ntp_servers: - hostname: ptbtime1.ptb.de iburst: yes nts: yes roles: - rhel-system-roles.timesync ptbtime1.ptb.de is an example of public server. You may want to use a different public server or your own server. Optional: Verify playbook syntax. Run the playbook on your inventory file: Verification Perform a test on the client machine: Check that the number of reported cookies is larger than zero. Additional resources chrony.conf(5) man page 21.4. timesync System Roles variables You can pass the following variable to the timesync role: timesync_ntp_servers : Role variable settings Description hostname: host.example.com Hostname or address of the server minpoll: number Minimum polling interval. Default: 6 maxpoll: number Maximum polling interval. Default: 10 iburst: yes Flag enabling fast initial synchronization. Default: no pool: yes Flag indicating that each resolved address of the hostname is a separate NTP server. Default: no nts: yes Flag to enable Network Time Security (NTS). Default: no. Supported only with chrony >= 4.0. Additional resources For a detailed reference on timesync role variables, install the rhel-system-roles package, and see the README.md or README.html files in the /usr/share/doc/rhel-system-roles/timesync directory.

Commands:
--- - hosts: timesync-test vars: timesync_ntp_servers: - hostname: 2.rhel.pool.ntp.org pool: yes iburst: yes roles: - rhel-system-roles.timesync
ansible-playbook --syntax-check playbook.yml
ansible-playbook -i inventory_file /path/to/file/playbook.yml
--- - hosts: timesync-test vars: timesync_ntp_servers: - hostname: ptbtime1.ptb.de iburst: yes nts: yes roles: - rhel-system-roles.timesync
ansible-playbook --syntax-check playbook.yml
ansible-playbook -i inventory_file /path/to/file/playbook.yml
chronyc -N authdata Name/IP address Mode KeyID Type KLen Last Atmp NAK Cook CLen ===================================================================== ptbtime1.ptb.de NTS 1 15 256 157 0 0 8 100