Fix a corrupted RSA key on an Amazon

  1. The machine must be EBS based.
  2. Create a new t1.micro instance in the same availability zone as the affected machine with a new Tag name but pointing to same key pair as the affected machine is pointed to.
  3. Stop the affected machine (do not terminate) – this is only possible with EBS machines)
  4. Detach the EBS volume from the affected machine (by default attached as /dev/sda1)
  5. Attach the detached EBS device to the new machine at location (e.g. /dev/sda2)
  6. SSH into the new machine using putty and mount the affected machine’s root filesystem (/dev/sda2) to somewhere (e.g. in /mnt/fs) and edit the authorized_keys file at location /mnt/fs/sda2/root/.ssh/authorized_keys  for root or /home/user/.ssh/authorized_keys for user  and add your existing key-pair public key to it.

Command to mount affected machine’s root file system to new machine’s /mnt directory:

mount /dev/sda2 /mnt/fs

cd /mnt/fs/root/.ssh

vi authorized_keys

  1. Once changes are done, unmount the affected volume. Stop the new machine, detach the volume from it and terminate the new machine.

Command to unmount:

umount /mnt/fs

  1. Re-attach the affected device to the affected machine (which is already stopped) – ensure to attach it as the same device it was before (e.g. /dev/sda1)
  2. Re-start your old machine. ssh to the machine and you should be able to use your old machine.

You can also view other big data tutorials here.

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About Sharmistha Chakraborty

Sharmistha is currently working as a Big Data Architect with Accenture concentrating on distributed computing areas with focus on Hadoop and its eco system and NOSQL data store. Her job includes understanding business needs, performing complex analysis on huge volume of unstructured, structured and poly structured data, exploring the pattern of data and deriving intelligence out of data to accelerate the pace of innovation. She is also involved in defining and designing execution architecture, build big data solution platform for different industry aligned clients.
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