Distributed Host Setup

This guide will demonstrate configuring a distributed runtime with multiple hosts on a single subnet.

For each host in a distributed runtime:

  • Designate an Ethernet interface and IP subnet for Core nodes to use
  • Determine and set a unique IP address within the defined subnet
  • Set up the Core SDF
  • Optionally configure the PTP master clock for host synchronization
    • PTP runs in hybrid mode with the default configuration

1. PolySync Core bus Ethernet interface

Each host must designate one Ethernet interface for the PolySync Core bus . On Linux systems the tool ifconfig is used to list all useable interfaces detected by the kernel.

$ ifconfig

Select an interface, and connect an Ethernet cable between the local host and the network of distributed hosts.

1.1 Linux IP address

Select an IP subnet range that all distribtued hosts will share an IP address on, for example 192.168.200.XXX.

Select a unique static IP address within the subnet range for each distributed host. Configure the Ethernet interface to use a static IP address.

1.2. Core IP address

Use the Core Manager to update the Core configuration to use the static IP address.

$ polysync-core-manager -s 192.168.200.100

The IP address must exist on the host (shown through the ifconfig command) before Core nodes can start.

The DDS Discovery feature searches for other hosts within the IP subnet through the associated Ethernet interface. If other Core hosts exist on the network developers will be sharing the PolySync Core bus , meaning they see the other host’s data, and vice versa.

2. Update the SDF

Create or update the system SDF to represent the physical runtime, containing all hosts, their IP addresses, and the nodes connected to each host.

  • Add a host for each physical host ECU in the distributed runtime
    • Be sure to set the IP address to the static IP address from above
  • For each host, add a sensor node to the SDF for each sensor that’s physically connected to the host
  • Synchronize the SDF to all hosts in the distributed system
    • The psync.sdf file must be copied to the system SDF location in $PSYNC_USER_HOME/config/ on each host

2.1 Modifying a Tier 2 system SDF

To update Tier 2 host SDFs─for example to set a license file path or modify an existing node─use the SDF Configurator on a Tier 1 host and synchronize the new SDF with the distributed Tier 2 hosts.

3. PTP

The last requirement is to run Precision Time Protocol (PTP). Without the PTP service, hosts defined in the Core runtime will have differing system times and Core data will not be aligned or replayable.