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Creating keys with OpenSSH

Creating an SSH key pair using OpenSSH is an essential step for establishing a secure connection to your ccloud³ VMs at centron. Here’s how to do it:

Generating an SSH key pair with OpenSSH​

  1. Run SSH-Keygen:

    Open your terminal. Enter the command ssh-keygen to generate a 2048-bit RSA key pair. This is sufficient for most applications.

  2. Select a save location:

    You will be prompted to choose a location for the keys. By default, they are stored in the ~/.ssh directory, where id_rsa is the private key and id_rsa.pub is the public key. Using the default locations allows your SSH client to find your SSH keys automatically. It is recommended that you accept this by pressing ENTER.

    Generating public/private rsa key pair.
    Enter file in which to save the key (/home/username/.ssh/id_rsa):

  3. Take care with existing keys:

    If you have already generated a key pair, you may be prompted with a message stating that /home/username/.ssh/id_rsa already exists. If you choose to overwrite the key on the hard drive, you will no longer be able to use the previous key. Overwriting is an irreversible process.

  4. Enter an optional password:

    You will be prompted to enter an optional password, which will encrypt the private key file on the hard drive. If you enter a password, you will need to enter it every time you use this key. It is recommended that you use a password; however, you can skip this prompt by pressing ENTER.

    Created directory '/home/username/.ssh'.
    Enter passphrase (empty for no passphrase):
    Enter same passphrase again:

  5. Completion of the creation process

    Once the process is complete, you will have a public and a private key pair that you can use for authentication.

    Your identification has been saved in /home/username/.ssh/id_rsa.
    Your public key has been saved in /home/username/.ssh/id_rsa.pub.
    The key fingerprint is:
    a9:49:EX:AM:PL:E3:3e:a9:de:4e:77:11:58:b6:90:26 username@203.0.113.0
    The key's randomart image is:
    +--[ RSA 2048]----+
    |     ..o         |
    |   E o= .        |
    |    o. o         |
    |        ..       |
    |      ..S        |
    |     o o.        |
    |   =o.+.         |
    |. =++..          |
    |o=++.            |
    +-----------------+

Next steps​

Add a public key to your centron account:

Add your public key to your centron account so that it can be embedded in new ccloud³ VMs when they are created.

Adding a public key to existing ccloud³ VMs:

Add your public key to existing ccloud³ VMs to use SSH key authentication for logging in.

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