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Can we add/replace new keypair in a running VM?

asked 2018-02-27 01:39:37 -0500

udayutkarsh gravatar image
 I have a running VM with keypair injected at the time of creation. But I cannot find the ssh-key.pem file that was generated then. I do not have user/pass to log in. We used to log in only using .pem file. Is there any way to recover the .pem file or create new one and inject into vm?
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answered 2018-02-27 04:10:54 -0500

The term "injecting" is misleading. What actually happens: Nova provides the keypair in the metadata server or config drive, and the instance retrieves it from there when it boots up.

There is no command or API to add a keypair to a running instance. You could add a metadata item that contains the public key to a running instance, but this is pointless if the instance doesn't regularly check available metadata. The usual cloud images don't do that; you would have to create your own image. Which doesn't solve your acute problem.

Assuming your instance is implemented with libvirt rather than Hyper-V, VMware or another hypervisor, you could access its filesystem with a tool like guestmount or guestfish and set a root password or add a key. Where that filesystem is located depends on how you started the instance - ephemeral storage with a qcow2 file for backup, ephemeral storage with a raw file for backup, volume as root disk etc. Before you modify the filesystem, be sure to freeze the instance or shut it down.

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answered 2018-02-27 03:29:40 -0500

Deepa gravatar image

There are so many links you could refer here ..Few are below

If nothing works What you could do is take a snapshot, boot a new instance from that snapshot, and specify a key to get injected.

Best of luck !

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Asked: 2018-02-27 01:39:37 -0500

Seen: 935 times

Last updated: Feb 27 '18