Dynmon service¶
Dynmon is a transparent service that allows the dynamic injection of eBPF code in the linux kernel, enabling the monitoring of the network traffic and the collection and exportation of custom metrics.
This service exploits the capabilities of Polycube to replace the eBPF code running in the dataplane and the use of eBPF maps to share data between the control plane and the data plane.
Features¶
- Transparent service, can be attached to any network interface and Polycube services
- Support for the injection of any eBPF code at runtime
- Support for eBPF maps content exportation through the REST interface as metrics
- Support for two different exportation formats: JSON and OpenMetrics
Limitations¶
- The OpenMetrics format does not support complex data structures, hence the maps are exported only if their value type is a simple type (structs and unions are not supported)
- The OpenMetrics Histogram and Summary metrics are not yet supported
How to use¶
Creating the service¶
#create the dynmon service instance
polycubectl dynmon add monitor
Configuring the data plane¶
In order to configure the dataplane of the service, a configuration JSON object must be sent to the control plane; this action cannot be done through the polycubectl tool as it does not handle complex inputs.
To send the data plane configuration to the control plane it is necessary to exploit the REST interface of the service, applying a PUT
request to the /dataplane
endpoint.
Configuration examples can be found in the examples directory.
Attaching to a interface¶
# Attach the service to a network interface
polycubectl attach monitor eno0
# Attach the service to a cube port
polycubectl attach monitor br1:toveth1
Collecting metrics¶
To collect the metrics of the service, two endpoints have been defined to enable the two possible exportation formats:
JSON format
polycubectl monitor metrics show
OpenMetrics format
polycubectl monitor open-metrics show
Dynmon Injector Tool¶
This tool allows the creation and the manipulation of a dynmon cube without using the standard polycubectl CLI.
Running the tool¶
Usage: `dynmon_injector.py [-h] [-a ADDRESS] [-p PORT] [-v] cube_name peer_interface path_to_dataplane`
positional arguments:
cube_name indicates the name of the cube
peer_interface indicates the network interface to connect the cube to
path_to_dataplane indicates the path to the json file which contains the new dataplane configuration
which contains the new dataplane code and the metadata associated to the exported metrics
optional arguments:
-h, --help show this help message and exit
-a ADDRESS, --address ADDRESS set the polycube daemon ip address (default: localhost)
-p PORT, --port PORT set the polycube daemon port (default: 9000)
-v, --version show program's version number and exit
Usage examples¶
basic usage:
./dynmon_injector.py monitor_0 eno1 ../examples/packet_counter.json
setting custom ip address and port to contact the polycube daemon:
./dynmon_injector.py -a 10.0.0.1 -p 5840 monitor_0 eno1 ../examples/packet_counter.json
This tool creates a new dynmon cube with the given configuration and attaches it to the selected interface.
If the monitor already exists, the tool checks if the attached interface is the same used previously; if not, it detaches the cube from the previous interface and attaches it to the new one; then, the selected dataplane is injected.