Exit device-module-test early if we detect other running netlab instances

[snuffy22]

This provides a early escape when trying to run tests and you have another 'default' netlab lab already running.

Mentioned in #3604

Conditional that it only cares if user is trying to run the up case where it would clash with an existing lab.

(py3-snuff) netlab@netlab:~/snuffy-netlab/tests/integration$ ./device-module-test -p clab -d frr  --steps create bgp
Pre-test cleanup:
17:09:48 bgp/01-ebgp-session.yml: create(ok) up(skip) config(skip) validate(skip) cleanup(ok)
17:09:49 bgp/02-ibgp-ebgp-session.yml: create(ok) up(skip) config(skip) validate(skip) cleanup(ok)

(py3-snuff) netlab@netlab:~/snuffy-netlab/tests/integration$ ./device-module-test -p clab -d frr  bgp
Running netlab lab 'default' instance detected:
Active lab instance(s)

id           directory                                    status     providers
------------ -------------------------------------------- ---------- --------------------
default      ...me/netlab/snuffy-netlab/tests/integration started    clab

[FATAL]   Refusing to launch integration test while another 'default' netlab lab is running

[snuffy22]

@ipspace maybe i'm solving this in the wrong place..
I think fixing in the netlab up cli is probably better.. thoughts?

[snuffy22]

mm netlab up seems to have that protection.. I should have tested before I spoke

But one thing I did notice, the running of pre-test cleanup breaks the output of the currently running lab that is still up.

This is without my patch..

My running default lab, before trying device-module-test

(py3-snuff) netlab@netlab:~/snuffy-netlab/tests/integration$ netlab status --all --format json
Active lab instance(s)

┏━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━━━┓
┃ id      ┃ directory                                                ┃ status  ┃ providers ┃
┡━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━━━┩
│ default │ /home/netlab/snuffy-netlab/tests/integration/ospf/ospfv2 │ started │ clab      │
└─────────┴──────────────────────────────────────────────────────────┴─────────┴───────────┘

After doing device-module-test in normal netlab status --all

py3-snuff) netlab@netlab:~/snuffy-netlab/tests/integration$ ./device-module-test -p clab -d frr bgp
[sudo] password for netlab:
Pre-test cleanup:
19:53:33 bgp/01-ebgp-session.yml: create(ok) up(FAIL) cleanup(ok)
19:53:34 bgp/02-ibgp-ebgp-session.yml: create(ok) up(FAIL) cleanup(ok)
19:53:36 bgp/03-ibgp-rr.yml: create(ok) up(FAIL) cleanup(ok)
19:53:37 bgp/04-originate.yml: ^C

[FATAL]   netlab down --cleanup failed, check the log files in /tmp/netlab_log

(py3-snuff) netlab@netlab:~/snuffy-netlab/tests/integration$ netlab status --all 
Active lab instance(s)

┏━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━┓
┃ id      ┃ directory                                                ┃ status                 ┃ providers ┃
┡━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━┩
│ default │ /home/netlab/snuffy-netlab/tests/integration/ospf/ospfv2 │ stopping clab provider │ clab      │
└─────────┴──────────────────────────────────────────────────────────┴────────────────────────┴───────────┘

After with json output

(py3-snuff) netlab@netlab:~/snuffy-netlab/tests/integration$ netlab status --all --format json
{
  "default": {
    "dir": "/home/netlab/snuffy-netlab/tests/integration/ospf/ospfv2",
    "providers": [
      "clab"
    ],
    "log_line": "OK: sudo -E containerlab destroy --cleanup -t clab.yml",
    "log": [
      "2026-07-10T18:09:46.788605-04:00: OK: containerlab version",
      "2026-07-10T18:09:46.803499-04:00: OK: bash -c [[ `containerlab version|awk '/version/ {print $2}'` > '0.74.99' ]] && echo OK",
      "2026-07-10T18:09:46.842268-04:00: OK: docker image ls --format json quay.io/frrouting/frr:10.6.1",
      "2026-07-10T18:09:46.843868-04:00: restarting lab",
      "2026-07-10T18:09:46.846365-04:00: starting provider clab",
      "2026-07-10T18:09:48.707586-04:00: OK: sudo -E containerlab deploy --reconfigure -t clab.yml",
      "2026-07-10T18:09:48.709698-04:00: clab workload started",
      "2026-07-10T18:09:48.711610-04:00: deploying initial configuration",
      "2026-07-10T18:09:48.847956-04:00: deploying configuration: complete configuration",
      "2026-07-10T18:09:52.800956-04:00: configuration deployment complete",
      "2026-07-10T18:09:52.832012-04:00: OK: netlab initial --no-message --deploy",
      "2026-07-10T18:09:52.834547-04:00: initial configuration complete",
      "2026-07-10T18:09:52.836745-04:00: started",
      "2026-07-10T19:53:34.798429-04:00: lab shutdown requested in conflicting directory",
      "2026-07-10T19:53:34.813251-04:00: OK: containerlab version",
      "2026-07-10T19:53:34.830172-04:00: OK: bash -c [[ `containerlab version|awk '/version/ {print $2}'` > '0.74.99' ]] && echo OK",
      "2026-07-10T19:53:34.833622-04:00: stopping clab provider",
      "2026-07-10T19:53:34.880416-04:00: OK: sudo -E containerlab destroy --cleanup -t clab.yml",
      "2026-07-10T19:53:36.020868-04:00: lab shutdown requested in conflicting directory",
      "2026-07-10T19:53:36.035809-04:00: OK: containerlab version",
      "2026-07-10T19:53:36.052394-04:00: OK: bash -c [[ `containerlab version|awk '/version/ {print $2}'` > '0.74.99' ]] && echo OK",
      "2026-07-10T19:53:36.056043-04:00: stopping clab provider",
      "2026-07-10T19:53:36.104211-04:00: OK: sudo -E containerlab destroy --cleanup -t clab.yml",
      "2026-07-10T19:53:37.294479-04:00: lab shutdown requested in conflicting directory",
      "2026-07-10T19:53:37.310224-04:00: OK: containerlab version",
      "2026-07-10T19:53:37.328416-04:00: OK: bash -c [[ `containerlab version|awk '/version/ {print $2}'` > '0.74.99' ]] && echo OK",
      "2026-07-10T19:53:37.333138-04:00: stopping clab provider",
      "2026-07-10T19:53:37.382554-04:00: OK: sudo -E containerlab destroy --cleanup -t clab.yml"
    ],
    "timestamp": "2026-07-10 23:53:37.382554+00:00",
    "status": "stopping clab provider",
    "name": "ospfv2"
  }
}

[ipspace]

Two major changes:

• Don't run a subprocess. Use the utils.status.read_status function
• Don't assume you have to check the default instance. I'm using the multilab plugin, so the integration tests don't interfere with other stuff I'm doing. That instance needs to be checked.