riaps-timesync

Time synchronization service, instrumentation and tests for the RIAPS platform.

Time synchronization configuration tool: timesyncctl

The release (.deb) packages contain a configuration tool, called timesyncctl for an easy, semi-automated way for configuring a node for distributed time synchronization. The tool configures and checks the status of the ChronoCape board (if needed) in the device tree and controls all services (GPSd, chrony, phc2sys, ptp4l, etc) needed in a specific role.

Notes:

• The tool is installed under /usr/local/bin (starting in v1.1.17, previous version were in /opt/riaps/*<arch>*/bin, where *<arch>* is either armhf or amd64).

• Some operations (config and restart) needs root privileges, thus you need to run the tool as root or with the sudo command

The following time synchronization roles are supported:

• master: the node is synchronized to (1) GPS (using the ChronoCape board) or (2) NTP (well-known internet server) or (3) NTP (the control/VM host) in this order. Selecting the best reference clock is automatic. It also acts as a PTP master on the local network.

• standalone: same as master, but PTP master role is disabled.

• slave: the node is forced to use PTP in slave mode. Needs a PTP master on the local network.

Running timesyncctl:

• timesyncctl config: will list the available roles.
• timesyncctl config <role>: will change the node's configuration for the given role and will restart the services. Needs root privileges.
• timesyncctl restart: will restart the services in the current role. Needs root privileges.
• timesyncctl status: check the status of the services and device tree in the current role.

Examples:

To configure the node for a master role:

sudo timesyncctl config master

To check if everything is as expected in the current role:

timesyncctl status

Note: This package is currently optimized for the BBB Remote nodes (which use all available modes). The RIAPS VM (amd64 package) is intended to stay in standalone mode since we are using a virtual machine and hardware timestamping is not available. The Raspberry Pi 3/4 and Jetson Nano do not support hardware timestamping, so only the standalone mode is also used for arm64 packages here.

Check Node Synchronization

An easy way to test that time is synchronized across nodes is to do the following on each node (including the VM):

git clone https://github.com/RIAPS/riaps-timesync.git
cd riaps-timesync/python
python3 test-timesync.py

This will provide time from riaps_timesync (riaps_ts) continuously until you use Ctrl C to stop it. You can see that each of the nodes are sync’ed by comparing the output from this test. Here is an example of the test output:

wake: 1637275707.000529669 secs
wake: 1637275708.000811827 secs
wake: 1637275709.000351160 secs

To do these commands using riaps_fab, use the following putting in the above command:

riaps_fab sys.run:’”<command>”’

Note: to stop the program you need to do Ctrl C on the node or use riaps_fab sys.sudo:’”pkill -f test_timesync.py”’