With a secure shell (SSH) key pair, you can create virtual machines (VMs) in Azure that use SSH keys for authentication, eliminating the need for passwords to sign in. This article shows you how to quickly generate and use an SSH public-private key file pair for Linux VMs. You can complete these steps with the Azure Cloud Shell, a macOS or Linux host, the Windows Subsystem for Linux, and other tools that support OpenSSH.
Note
VMs created using SSH keys are by default configured with passwords disabled, which greatly increases the difficulty of brute-force guessing attacks.
Aug 22, 2017 $ openssl rsa -passin pass:x -in server.pass.key -out server.key # We no longer need the 'server.pass.key' $ rm server.pass.key $ server.key is a PEM RSA private key. To know more about what is a PEM file and it’s significance, read What is a Pem file and how does it differ from other OpenSSL Generated Key File Formats? At serverfault.com.
For more background and examples, see Detailed steps to create SSH key pairs.
For additional ways to generate and use SSH keys on a Windows computer, see How to use SSH keys with Windows on Azure.
Azure currently supports SSH protocol 2 (SSH-2) RSA public-private key pairs with a minimum length of 2048 bits. Other key formats such as ED25519 and ECDSA are not supported.
Use the ssh-keygen command to generate SSH public and private key files. By default, these files are created in the ~/.ssh directory. You can specify a different location, and an optional password (passphrase) to access the private key file. If an SSH key pair with the same name exists in the given location, those files are overwritten.
The following command creates an SSH key pair using RSA encryption and a bit length of 4096:
If you use the Azure CLI to create your VM with the az vm create command, you can optionally generate SSH public and private key files using the --generate-ssh-keys option. The key files are stored in the ~/.ssh directory unless specified otherwise with the --ssh-dest-key-path option. The --generate-ssh-keys option will not overwrite existing key files, instead returning an error. In the following command, replace VMname and RGname with your own values:
To create a Linux VM that uses SSH keys for authentication, specify your SSH public key when creating the VM using the Azure portal, Azure CLI, Azure Resource Manager templates, or other methods:
If you're not familiar with the format of an SSH public key, you can display your public key with the following cat command, replacing ~/.ssh/id_rsa.pub with the path and filename of your own public key file if needed:
A typical public key value looks like this example:
If you copy and paste the contents of the public key file to use in the Azure portal or a Resource Manager template, make sure you don't copy any trailing whitespace. To copy a public key in macOS, you can pipe the public key file to pbcopy. Similarly in Linux, you can pipe the public key file to programs such as xclip.
The public key that you place on your Linux VM in Azure is by default stored in ~/.ssh/id_rsa.pub, unless you specified a different location when you created the key pair. To use the Azure CLI 2.0 to create your VM with an existing public key, specify the value and optionally the location of this public key using the az vm create command with the --ssh-key-values option. In the following command, replace VMname, RGname, and keyFile with your own values:
If you want to use multiple SSH keys with your VM, you can enter them in a space-separated list, like this --ssh-key-values sshkey-desktop.pub sshkey-laptop.pub.
With the public key deployed on your Azure VM, and the private key on your local system, SSH into your VM using the IP address or DNS name of your VM. In the following command, replace azureuser and myvm.westus.cloudapp.azure.com with the administrator user name and the fully qualified domain name (or IP address):
If you specified a passphrase when you created your key pair, enter that passphrase when prompted during the login process. The VM is added to your ~/.ssh/known_hosts file, and you won't be asked to connect again until either the public key on your Azure VM changes or the server name is removed from ~/.ssh/known_hosts.
If the VM is using the just-in-time access policy, you need to request access before you can connect to the VM. For more information about the just-in-time policy, see Manage virtual machine access using the just in time policy.
For more information on working with SSH key pairs, see Detailed steps to create and manage SSH key pairs.
If you have difficulties with SSH connections to Azure VMs, see Troubleshoot SSH connections to an Azure Linux VM.
Last updated 29 February 2012.
This will step you through the process of generating a SSH keypair on Mac OS X. Begin by opening your Terminal, generally found in the 'Utilities' subdirectory of your 'Applications' directory.
Before you generate your keypair, come up with a passphrase. The rules for good passwords also apply here: mix of upper and lower case, numbers, spaces and punctuation. Limit it to less than 31 characters.
Now, generate your keypair! Enter the following: /dishonored-2-serial-key-generator.html.
Ssh generate public key from private linux. $ ssh-keygen -t rsa -C 'yourname@yourdomain.ext'
Note: Do not type the dollar sign above; it is an example of the default command prompt shown by Mac OS X. Your actual prompt may be different. In the example above and below, the actual part you should type is the part that follows the dollar sign.
Your terminal should respond:
Press Return to accept the default value. Your terminal should respond:
Enter passphrase (empty for no passphrase):
Enter the passphrase you decided on above. The response will be:
Enter same passphrase again:
Enter the passphrase again and press Return. The program will think a bit, and respond with something like this. Note that many of the details in the example below are just for example purposes; much of the actual output you see will differ from the below.
You can use the pbcopy utility to easily insert your public key (or other text files) into your Mac's clipboard so that you can add it to your Drupal.org profile, GitHub, or other places. The filename should be yourfilename.pub - with yourfilename being the filename you entered when you first created this file. If you just hit enter, the default is id_rsa.pub.
$ pbcopy < ~/.ssh/id_rsa.pub
You won't see any output in the terminal, but the contents of your public key will now be in your clipboard and can be easily pasted anywhere where you can normally paste text.
In case you're curious, the pbpaste utility works the other way, allowing you to easily grab the contents of the clipboard for use in the terminal. For example, the following command will write the contents of the clipboard to a file:
$ pbpaste > ~/clipboard.text
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