Setup and trace a cluster using LTTng

• Start and stop tracing in parallel (DONE)
• Execute a command remotely under tracing (DONE)
• Collect traces either live after tracing (DONE)
• Install LTTng (stable, devel, addons, etc.) (see scripts)
• Check if tracer is available (TODO)
• Start/stop/restart lttng-sessiond (TODO)

Requirements:

• fabric
• python-yaml

Install requirements for Ubuntu 14.04: sudo apt-get install fabric python-yaml

Install command: sudo python setup.py install

Or run it from the repo by sourcing env.sh.

You need a recipe file to set variables of the experiment and define commands to executes under tracing. The recipe is a YAML file. Common settings can be imported. If a setting is redefined in a file, it overrides the imported setting.

The following settings are available:

• username: SSH user to connect to the remote hosts. Public key must be configured for password less connexion. (string)
• events: (only kernel events are supported for now) ** kernel: list of kernel events to enable (list)
• import: yaml file to import (without .yaml, must be in the same directory) (string)
• roledefs: named group of machines. (dict)
• execute: commands to executes under tracing (list of dict) ** command: shell command, where %(key)s are substituted at runtime with the powerset of parameters (see parameters below) ** roles: groups to run the command on (list) ** method: either background (non-blocking) or foreground (blocking), default foreground. If a command is spawned in the background, make sure to include a command to terminate the task at the end, because they are not terminated automatically.
• parameters: define parameter values to be used in commands. One trace will be generated for each combinations of parameters. The trace directory includes parameters values. (dict)

See files recipe/base.yaml and recipe/sleep.yaml for examples.

The following command runs the experiment:

lttng-cluster recipe trace recipe/sleep.yaml

And produces the following traces under ~/lttng-traces/ of the machine where the command is launched: sleep-20141130-184830-delay=1 sleep-20141130-184830-delay=2 sleep-20141130-184830-delay=3

Happy hacking!