Starting PolySync PTP when the machine boots

The PolySync PTP service is required for both record and replay operations on distributed systems. PTP stands for Precision Time Protocol, and enables multi-host clock synchronization implemented through IEEE-1588.

You can start PolySync PTP when the machine boots where it spawns into a daemon that runs in the background. Once configured, this can be left untouched. The steps to start PTP at boot are documented here.

This article details how to start PolySync PTP service when the machine boots. This can be done using a pre-built script that utilizes the PolySync Manager. Starting PTP services requires sudo access.

Set PolySync Interface Address

Before you can start PTP services you must designate the static IP address that connects this machine to the PolySync Ethernet bus. For distributed systems you will need to pick a subnet for all machines to identify on with a unique IP address. The default subnet is 192.168.200.XXX. The PolySync Manager will need to be run to update the IP address on each of the distributed machines.

$ polysync-manager -s 192.168.200.XXX

Start PTP On Machine Boot

To start this service when the machine boots we will modify the crontab for the sudo user.

$ sudo crontab -e

Next, enter the following line at the bottom of the file:

@reboot /usr/local/polysync/utils/polysync_start_ptp.sh

Once you reboot the machine PTP will be active.

Start PTP Manually

To start PTP manually you can use the pre-built script or start the PTP dameon using the PolySync Manager.

$ sudo -E $PSYNC_HOME/utils/polysync_start_ptp.sh

To start PTP with the Manager pass the '-p' flag.

$ sudo -E $PSYNC_HOME/bin/polysync-manager -p

PTP daemon can be stopped using the '-l' flag.

$ sudo -E $PSYNC_HOME/bin/polysync-manager -l

Note: to retain the environment variables all sudo commands must be called with the '-E' flag.