cannot start elastalert-server - python cannot be run from node

[psenicka1301]

Hello, we have a problem to start elastalert-server, it always finishes with error:

08:01:20.944Z  INFO elastalert-server: ProcessController:  Starting ElastAlert
08:01:20.944Z  INFO elastalert-server: ProcessController:  Creating index
08:01:21.458Z ERROR elastalert-server: ProcessController:  Index create exited with code null
08:01:21.459Z  WARN elastalert-server: ProcessController:  ElastAlert will start but might not be able to save its data!

more logs on createIndex:

08:15:55.916Z  INFO elastalert-server:
    ProcessController:  {
      status: null,
      signal: 'SIGKILL',
      output: [ null, <Buffer >, <Buffer > ],
      pid: 135,
      stdout: <Buffer >,
      stderr: <Buffer >
    }

we have changed the config for our needs, we have volumes for rules and rule-templates mapped, and we have copied one of example rule to rules it seems to be a problem to run python from node, because outside node, we can run elastalert.py, or create_index.py Are we missing something or can you please help us to find where is the problem? Thank you