Check dependencies early and explicitely

[ycongal-smile]

The playbooks have recursively some dependencies. It would be better to check is they are satisfied early in playbooks deployment, ideally with an explicit error message.

For example, here the missing dependencies I have run into:

• localhost needs matplotlib
• subscriber need rsync, psmisc, tshark

[ycongal-smile]

Another element that could be checked:

• sudo must be configured on the subscriber
• User root is most likely the best bet seeing what the script does on each target (dump interfaces, install bpf programs, RT priority, ...)

[ycongal-smile]

Another thing to check : A sv_timestamp_logger container must not exist before running the tool:

fatal: [10.0.0.2]: FAILED! => 
{
  "changed": true,
  "cmd": [ "docker", "run", "--privileged", "-d", "-v", "/tmp:/tmp", "--cpuset-cpus=1", "--name", "sv_timestamp_logger", "--network=host", "sv_timestamp_logger", "-d", "enp24s0", "-f", "/tmp/ts_sv_10.0.0.2", "-s", "4001", "--first_SV_cnt", "280", "-t", "--max_SV_cnt", "4000" ],
  "delta": "0:00:00.019005",
  "end": "2024-10-28 10:39:31.748123",
  "msg": "non-zero return code",
  "rc": 125,
  "start": "2024-10-28 10:39:31.729118",
  "stderr": "docker: Error response from daemon: Conflict. The container name \"/sv_timestamp_logger\" is already in use by container \"eadeb3effe78c8fbcc53d5b06cbb74f48f5a495ac0bdfe0456abe4b66e42aa45\". You have to remove (or rename) that container to be able to reuse that name.\nSee 'docker run --help'.",
  "stderr_lines": [
    "docker: Error response from daemon: Conflict. The container name \"/sv_timestamp_logger\" is already in use by container \"eadeb3effe78c8fbcc53d5b06cbb74f48f5a495ac0bdfe0456abe4b66e42aa45\". You have to remove (or rename) that container to be able to reuse that name.",
    "See 'docker run --help'."
  ],
  "stdout": "",
  "stdout_lines": []
}

[Paullgk]

Hello Yoann,

• We are planning to improve the README to provide a clearer description of the dependencies required to run svtrace. This update should be available soon. Additionally, target package dependencies could be verified through assertions in a test playbook.

• Regarding the Sudo check, we assume that the user executing the Ansible playbook has sufficient privileges to run commands on the target, using become: true. The privileges escalation is already done by Ansible.

[ycongal-smile]

Hello Yoann,

• We are planning to improve the README to provide a clearer description of the dependencies required to run svtrace. This update should be available soon. Additionally, target package dependencies could be verified through assertions in a test playbook.

Awesome!

• Regarding the Sudo check, we assume that the user executing the Ansible playbook has sufficient privileges to run commands on the target, using become: true. The privileges escalation is already done by Ansible.

Please check this assumption. Or have a clear documentation for the user variable.