identity: derive stable management server id (msid) from FQDN

[poddm]

---

Description

This PR makes the management server node id (msid) stable across restarts by adding an opt-in mode that derives it from the node FQDN instead of the host MAC address.

By default, ManagementServerNode derives the msid from the host hardware MAC address (MacAddress.getMacAddress().toLong()). In environments where the MAC address is not stable across restarts (e.g. certain virtualized/containerized hosts), the msid changes on restart. This orphans the mshost row and breaks any state keyed on the node id — async jobs, HA work (fk_op_ha_work__mgmt_server_id), and router/stats ownership.

This change:

• Adds an opt-in FQDN mode: when the environment variable CLOUDSTACK_MSID_FROM_FQDN=true (or the system property cloudstack.msid.from.fqdn=true) is set, the msid is derived from a SHA-256 hash of the node's canonical FQDN, which stays stable across restarts. Default behavior (MAC-based) is unchanged.
• Fails cleanly: if the FQDN cannot be resolved, ManagementServerNode records the cause and returns an invalid id (0) rather than silently reverting to the unstable MAC-based id. The invalid id makes the system-integrity check() fail startup cleanly instead of raising an ExceptionInInitializerError from static initialization.
• Centralizes node-identity access: all consumers now obtain the id from ManagementServerNode.getManagementServerId() so they agree on the same value — StatsCollector, ManagementServerImpl, NetworkUsageManagerImpl, VirtualNetworkApplianceManagerImpl, and CloudZonesStartupProcessor (previously some called MacAddress.getMacAddress().toLong() directly).
• Logs the resolved id and its source (mac-address / fqdn:<name>) at startup for observability.

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)
• Build/CI
• Test (unit or integration test code)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• Major
• Minor

Bug Severity

• BLOCKER
• Critical
• Major
• Minor
• Trivial

Screenshots (if appropriate):

N/A

How Has This Been Tested?

• Added ManagementServerNodeTest covering both derivation modes (MAC-based default and FQDN-based opt-in), including the failure path that yields an invalid id.
• Verified default (MAC) behavior is unchanged when the env var/system property is unset.
• Verified that with CLOUDSTACK_MSID_FROM_FQDN=true, the derived id is positive, non-zero, and identical across restarts for the same FQDN.
• Verified that all updated consumers resolve the same id via ManagementServerNode.getManagementServerId().

How did you try to break this feature and the system with this change?

• Enabled FQDN mode on a host with an unresolvable/misconfigured hostname to confirm startup fails cleanly (integrity check throws with the recorded cause) rather than reverting to an unstable id or throwing ExceptionInInitializerError.
• Checked truthy parsing variants (true, 1, yes, mixed case, surrounding whitespace) and confirmed unset/false/empty values keep the default MAC-based behavior.
• Confirmed the 48-bit derived id is masked positive and never 0 for a valid FQDN.