Multi-Robot Kubernetes automatic SYSID allocation

[mhl787156]

This PR implements automatic SYSID allocation for multi-robot applications. it is still WIP. It contains the following

• Augmented entrypoint for both starling-sim-base-px4 and starling-sim-px4-sitl to manipulate PX4_INSTANCE
  • Current solution if PX4_INSTANCE is zero, then the last digit of the IP is used, otherwise the value is kept. However this was deemed no suitable by #24 comment
• Similarly for starling-mavros mavros_setup.sh modifies MAVROS_TGT_SYSTEM. If it is zero, first a lookup (to be implemented) to /etc/drone.config will be conducted, if no such file exists, it falls back to setting by ip address.
• In order for gazebo model creation to work, several changes have been made
  • k8.gazebo-iris.amd64.yaml now only deploys the base gzweb (starling-sim-iris) with no models
  • k8.px4-sitl.amd64.yaml now also deploys starling-sim-iris with spawn-only command running. This is also now StatefulSet rather than standard Deployment in order to generate ordinal
  • Unfortunately, the SITL simulation port is hard coded into the xacro model file. So In order for the spawned drone to talk to SITL, the xacro_launch.sh is injected into ros.env.d of the iris Dockerfile. This script generates an sdf model file with the mavlink_tcp_port set to PX4_SITL_PORT which should be 4560 + px4instance. It is saved in /tmp/_.sdf and the iris launch file now spawns this model file.
• From suggestion in #24, instead of SITL setting udp to min(14549, 14540+px4_instance) see PX4 startup script we just fix it to 14540 using sed in sitl.Dockerfile. Then MAVROS_FCU_URL's default deals with the connection.
• A couple of extra kubernetes bash scripts have also been added to /scripts/ for ease of testing

Problems:

• Remembering that PX4_INSTANCE + 1 = MAVROS_TGT_SYSTEM may cause (and has caused) issues in the future, perhaps we can combine these into a TARGET_SYSTEM env variable for which the entrypoints deal with. See #24 comment
• Example controller needs to manually specify vehicle through newly added TARGET_SYSTEM environment variable. Now solved with a launch script which autodetects mavros topics being broadcast and runs an example controller for each instance.

TODO:

• [x] Move from IP address to StatefulSet ordinal.
• [x] Agree on IP Address ranges for SITL and Real Drones, and determine a method for communicating these ranges to starling_mavros

[mhl787156]

StatefulSet generates an ordinal which is exposed through the pod name. The pod name is used as pod hostname. The ordinal itself is not stored so must be parsed from either VEHICLE_NAMESPACE or hostname. hostname was decided in order to reduce differences between px4 and mavros container setup.

Most recent update has two core changes:

• px4 container entrypoint.sh
  • Added a new env variable PX4_SYSID_SITL_BASE to set lowest SYSID allocated to SITL. Currently defaults to 150 in sitl.Dockerfile
  • PX4_INSTANCE is set to PX4_SYSID_SITL_BASE + ORDINAL - 1. The -1 is required in order to align with Mavros target_id
• mavros container mavros_setup.sh
  • Added a new env variable MAVROS_TGT_SYSTEM_BASE set to lowest tgt value. Default is zero set in Mavros Dockerfile. For SITL purposes, this is set identical to PX4_SYSID_SITL_BASE in the k8 config file
  • MAVROS_TGT_SYSTEM is set to PX4_SYSID_SITL_BASE + ORDINAL