doc/manuals/chapters/troubleshooting.adoc

== Troubleshooting

=== Format: YAML, and its Drawbacks

The general configuration format used is YAML. The stock python YAML parser
does have several drawbacks: too many complex possibilities and alternative
ways of formatting a configuration, but at the time of writing seems to be the
only widely used configuration format that offers a simple and human readable
formatting as well as nested structuring. It is recommended to use only the
exact YAML subset seen in this manual in case the osmo-gsm-tester should move
to a less bloated parser in the future.

Careful: if a configuration item consists of digits and starts with a zero, you
need to quote it, or it may be interpreted as an octal notation integer! Please
avoid using the octal notation on purpose, it is not provided intentionally.

=== {app-name} not running but resources still allocated

The <<state_dir,reserved_resources.state>> is used to keep shared state of the
the resources allocated by any {app-name} instance. Each {app-name} instance
being run is responsible to de-allocate the used resources before exiting. In
general, upon receiving a shutdown action (ie. 'CTRL+C', 'SIGINT', python
exception, etc.), {app-name} is able to handle properly the situation and
de-allocate the resources before the process exits. Similarly, {app-name} also
takes care of terminating all its children processes being managed before
exiting itself.

However, under some circumstances, {app-name} will be unable to de-allocate the
resources and they will remain allocated for subsequent {app-name} instances
which try to use them. That situation is usually reached when someone terminates
{app-name} in a hard way. Main reasons are {app-name} process receiving a
'SIGKILL' signal ('kill -9 $pid') which cannot be caught, or due to the entire
host being shut down in a non proper way.

As a noticeable example, SIGKILL is known to be sent to {app-name} when it runs
under a jenkins shell script and any of the two following things happen:

- User presses the red cross icon in the Jenkins UI to terminate the running
  job.
- Connection between Jenkins master (UI) and Jenkins slave running the job is
  lost.

Once this situation is reached, one needs to follow 2 steps:

- Gain console access to the <<install_main_unit,Main Unit>> and manually clean
  or completely remove the 'reserved_resources.state' in the
  <<state_dir,state_dir>>. In general it's a good idea to make sure no
  {app-name} instance is running at all and then remove completely all files in
  <<state_dir,state_dir>>, since {app-name} could theoretically have been killed
  while writing some file and it may have ended up with corrupt content.
- Gain console access to the <<install_main_unit,Main Unit>> and each of the
  <<install_slave_unit,Slave Units>> and kill any hanging long-termed processes
  in there which may have been started by {app-name}. Some popular processes in
  this list include 'tcpdump', 'osmo-\*', 'srs*', etc.