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OpenStack has a useful rebuild function that allows you to rebuild an instance from a fresh image while maintaining the same fixed and floating IP addresses, amongst other metadata.
Web Interface
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1.
In Web Interface
Compute->Instances, select the VM you wish to associate the floating IP
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2.
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Click the drop-down menu on the right-hand side (in
Actionscolumn) and selectREBUILD INSTANCE
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Select the image from the drop-down menu in the pop-up. Click on the
REBUILDbutton.
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4.
The instance will be rebuilt with the new image
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Command-Line
Get the Server ID (Instance) and the Image ID
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