ENH: require config mode in order to run the provisioning playbook

[ZLLentz]

Description

This makes the provisioning workflow refuse to proceed if the PLC is not in config mode, for example if it is in run mode or some invalid or error mode.

Motivation and Context

From feedback in the TcBSD internal review: this is a simple way to stop ourselves from changing PLC configurations on active, running PLCs.

How Has This Been Tested?

Interactively on plc-tst-bsd2:

When in run mode:

$ ./scripts/provision_plc.sh plc-tst-bsd2
TcBSD key is registered with ssh agent
BECOME password:

PLAY [plc-tst-bsd2] **************************************************************************************************************************************************************************************************************************************************************************

TASK [Gathering Facts] ***********************************************************************************************************************************************************************************************************************************************************************
ok: [plc-tst-bsd2]

TASK [Verify connectivity with ping] *********************************************************************************************************************************************************************************************************************************************************
ok: [plc-tst-bsd2]

TASK [Run PLC mode command] ******************************************************************************************************************************************************************************************************************************************************************
ok: [plc-tst-bsd2]

TASK [Assert that PLC is in CONFIG mode] *****************************************************************************************************************************************************************************************************************************************************
fatal: [plc-tst-bsd2]: FAILED! => {"assertion": false, "changed": false, "evaluated_to": false, "msg": "PLC is in RUN mode! Abort!"}

PLAY RECAP ***********************************************************************************************************************************************************************************************************************************************************************************
plc-tst-bsd2               : ok=3    changed=0    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0

When in config mode:

$ ./scripts/provision_plc.sh plc-tst-bsd2
TcBSD key is registered with ssh agent
BECOME password:

PLAY [plc-tst-bsd2] ******************************************************************************************************************************************

TASK [Gathering Facts] ***************************************************************************************************************************************
ok: [plc-tst-bsd2]

TASK [Verify connectivity with ping] *************************************************************************************************************************
ok: [plc-tst-bsd2]

TASK [Run PLC mode command] **********************************************************************************************************************************
ok: [plc-tst-bsd2]

TASK [Assert that PLC is in CONFIG mode] *********************************************************************************************************************
ok: [plc-tst-bsd2]

TASK [Enable FreeBSD packages] *******************************************************************************************************************************
skipping: [plc-tst-bsd2]

(continues)

I also verified that this check works from a fresh install.

Where Has This Been Documented?

https://confluence.slac.stanford.edu/display/PCDS/TcBSD+Ansible+Workflows

Pre-merge checklist

• Code works interactively
• Code contains descriptive docstrings, including context and API
• Pre-commit passes on GitHub Actions
• Documentation under https://confluence.slac.stanford.edu/display/PCDS/TcBSD has been updated appropriately

[nrwslac]

Took some time to look through the ansible docs about playbooks, plays, and tasks. This looks correct to me.

[ghalym]

lgtm.