To access your Compute instances using SSH, generate an SSH key pair, associate the public key with your instances, and use the private key to log in to the instances using SSH.
- Nov 30, 2018 Sample set up for our RHEL 8 server. Where, You generate a key pair on your Linux/Unix/macOS desktop. Place the public key on RHEL 8 server. One can unlock public key using a private key stored on your desktop with the help of ssh command.
- Instead of using Amazon EC2 to create your key pair, you can create an RSA key pair using a third-party tool and then import the public key to Amazon EC2. For example, you can use ssh-keygen (a tool provided with the standard OpenSSH installation) to create a key pair.
Jan 28, 2016 Generating new ssh keys Post by taylorkh » Thu Jan 28, 2016 2:29 pm When I clone an OS image to a new, identical hardware PC I of course need to change the host name in a couple of places on the new machine.
Caution:
Keep your SSH keys secure. Lay down policies to ensure that the keys aren’t lost or compromised when employees leave the organization or move to other departments. If you lose your private key, then you can’t access your instances. For business continuity, ensure that the SSH keys of at least two IT system administrators are added to your instances.
Topics
Generate an SSH Key Pair on UNIX and UNIX-Like Systems
Use the following procedure to generate an SSH key pair on UNIX and UNIX-like systems:
- Run the
ssh-keygen
command.You can use the-t
option to specify the type of key to create.For example, to create an RSA key, run:You can use the-b
option to specify the length (bit size) of the key, as shown in the following example: - The command prompts you to enter the path to the file in which you want to save the key.A default path and file name are suggested in parentheses. For example:
/home/
user_name
/.ssh/id_rsa
. To accept the default path and file name, press Enter. Otherwise, enter the required path and file name, and then press Enter. - The command prompts you to enter a passphrase.The passphrase is not mandatory if you want to log in to an instance created using an Oracle-provided image. However, it is recommended that you specify a passphrase to protect your private key against unauthorized use.Note:With some images provided on Oracle Marketplace, the use of a passphrase might be mandatory.
- When prompted, enter the passphrase again to confirm it.
The command generates an SSH key pair consisting of a public key and a private key, and saves them in the specified path. The file name of the public key is created automatically by appending
.pub
to the name of the private key file. For example, if the file name of the SSH private key is id_rsa
, the file name of the public key would be id_rsa.pub
. Make a note of the path and file names of the private and public keys. When you create an instance, you must specify the SSH public key value. When you log in to an instance, you must provide the path to the corresponding SSH private key and you must enter the passphrase when prompted.
Generate an SSH Key Pair on Windows
You can generate an SSH key pair on a Microsoft Windows machine by using an application such as PuTTY. See the tutorial, Creating SSH Keys for Use with Oracle Cloud Services.
PuTTY is a free and open-source SSH and telnet client. It is primarily developed by Simon Tatham for Microsoft Windows but now it supports a wide variety of other operating systems. Public key authentication is a feature of PuTTY, in which, we can configure SSH Keys to allow password less logins to Linux machines from our PuTTY terminals.
In this article, we are configuring SSH Keys using PuTTYgen and then configure a CentOS 7 machine for password less logins by PuTTY client.
This Article Provides:
Environment Specification:
One Microsoft Windows based client and a CentOS 7 based server.
Generate SSH Keys using PuTTYgen:
PuTTYgen is included with PuTTY SSH client. Both are free and open source and distributed under MIT License. Therefore, it is available for free download at PuTTY official website.
We have already installed PuTTY SSH client on our MS Windows client.
Search and run PuTTYgen application.
Click on Generate button to generate a SSH Public/Private keys pair.
Meanwhile, we are required to scroll mouse in the area under the progress bar for randomization and generation of SSH Keys.
PuTTYgen has generated a SSH Public/Private keys pair.
Click on Save private key button to save the SSH Private Key locally.
Since, we are not defining any passphrase, therefore, PuTTYgen is displaying the above warning.
Ignore it and click on Yes.
Centos Generate Ssh Key Pair Authentication
We have saved our SSH Private Key in a local directory. You can also save your SSH Public Key in the same way, if you plan to use this same SSH Keys pair for more than one Linux machines.
Select the generated SSH Public Key and copy it to clipboard.
Configure SSH Keys for Password Less Logins to CentOS 7:
Connect to our CentOS 7 machine using PuTTY and insert SSH Public Key in ~/.ssh/authorized_keys file.
Now, open PuTTY and add a session for that CentOS 7 server.
![Create ssh key pair Create ssh key pair](https://blog.altoros.com/wp-content/uploads/2016/06/choose-the-instance-type.png)
Besides other settings, we are required to include our SSH Private Key as follows:
Save first and then open this session.
Our CentOS 7 server won’t prompt for a password this time.
Centos Create Ssh Key Pair
We have successfully configured SSH Keys using PuTTYgen for password less logins to Linux machines.