assign container rank via registration order

[jreadey]

container restarts can mix up the DN container ordering. This change should address that.

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Important

Assigns container rank by registration order and updates logging in headnode.py, azureBlobClient.py, and fileClient.py.

• Behavior:
  • Assigns container rank based on registration order in register() in headnode.py.
  • Maintains active_sn_ids and active_dn_ids lists to track active nodes.
  • Removes unhealthy nodes from active lists to make room for new registrations.
• Functions:
  • Adds getNodeUrls() in headnode.py to generate node URLs from active node IDs.
  • Modifies isClusterReady() in headnode.py to use active node lists for readiness checks.
• Logging:
  • Changes log level from warn to info for not found messages in get_object() in azureBlobClient.py and fileClient.py.

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[ellipsis-dev]

Avoid reusing the variable node_id inside the loops; it gets overwritten when iterating the active list. Use a distinct name (e.g. existing_node_id) for clarity.

[ellipsis-dev]

Avoid using id which shadows the built-in function. Use a more descriptive name like node_id for clarity.