backup: support imdsv2 only instance

[3pointer]

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[lilin90]

/lgtm

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Timeline:

• 2024-09-18 02:55:50.253501844 +0000 UTC m=+1016219.993925782: ☑️ agreed by hfxsd.
• 2024-10-14 03:47:10.019181289 +0000 UTC m=+242827.168091120: ☑️ agreed by lilin90.

[hfxsd]

/approve

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