[yang-models] device_metadata validation issue

[ganglyu]

Description

'DEVICE_METADATA': {'localhost': {'bgp_asn': '65100',
'cloudtype': None,
'cluster': 'AAA00PrdStr00',
'deployment_id': '1',
'docker_routing_config_mode': 'separated',
'hostname': 'switch-t0',
'hwsku': 'Force10-S6000',
'peer_switch': 'switch2-t0',
'region': None,
'resource_type': 'Storage',
'storage_device': 'true',
'subtype': 'DualToR',
'synchronous_mode': 'enable',
'type': 'ToRRouter'}},

https://github.com/Azure/sonic-buildimage/blob/master/src/sonic-config-engine/minigraph.py#L247-L248
Config db schema generated by minigraph can’t pass yang validation:
there's no 'cluster' in yang model.
It seems that we need to update yang model or sonic-config-engine.

Steps to reproduce the issue:

1. Run command 'sonic-cfggen -m tests/simple-sample-graph-case.xml -p t0-sample-port-config.ini --print-data'.
2. Use sonic_yang to validate config db schema.

Describe the results you received:

Yang validation failed.

Describe the results you expected:

Yang validation should pass.

Output of show version:

(paste your output here)

Output of show techsupport:

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Additional information you deem important (e.g. issue happens only occasionally):

[renukamanavalan]

@praveen-li , can you please look into this issue ?

[praveen-li]

@ganglyu Kindly follow this PR #6464.
This way you can add 'cluster' field by yourself and also can add tests.
Kindly let me know if any issues in understanding this, we can have a quick call b/w 5-6 PM PST anyday.