Jul 29, 2019 The ssh-keygen command creates a 2048-bit RSA key pair. For extra security, use RSA4096: ssh –keygen –t rsa 4096 If you’ve already generated a key pair, this will prompt to overwrite them, and those old keys will not work anymore. Dec 18, 2019 If there are existing keys, you can either use those and skip the next step or backup up the old keys and generate new ones. Generate a new 4096 bits SSH key pair with your email address as a comment by typing: ssh-keygen -t rsa -b 4096 -C '[email protected]' The output will look something like this.
![Pair Pair](https://programsbuzz.com:443/sites/default/files/styles/large/public/2018-03/sshkey.jpg?itok=pCkwGVuw)
- This module allows one to (re)generate OpenSSH private and public keys. It uses ssh-keygen to generate keys. One can generate
rsa
,dsa
,rsa1
,ed25519
orecdsa
private keys.
The below requirements are needed on the host that executes this module.
- ssh-keygen
Parameter | Choices/Defaults | Comments |
---|---|---|
attributes string | The attributes the resulting file or directory should have. To get supported flags look at the man page for chattr on the target system. This string should contain the attributes in the same order as the one displayed by lsattr. The = operator is assumed as default, otherwise + or - operators need to be included in the string. | |
comment added in 2.9 | Provides a new comment to the public key. When checking if the key is in the correct state this will be ignored. | |
force boolean |
| Should the key be regenerated even if it already exists |
group string | Name of the group that should own the file/directory, as would be fed to chown. | |
mode string | The permissions the resulting file or directory should have. For those used to /usr/bin/chmod remember that modes are actually octal numbers. You must either add a leading zero so that Ansible's YAML parser knows it is an octal number (like 0644 or 01777 ) or quote it (like '644' or '1777' ) so Ansible receives a string and can do its own conversion from string into number.Giving Ansible a number without following one of these rules will end up with a decimal number which will have unexpected results. As of Ansible 1.8, the mode may be specified as a symbolic mode (for example, u+rwx or u=rw,g=r,o=r ).As of Ansible 2.6, the mode may also be the special string preserve .When set to preserve the file will be given the same permissions as the source file. | |
owner string | Name of the user that should own the file/directory, as would be fed to chown. | |
path path / required | Name of the files containing the public and private key. The file containing the public key will have the extension .pub . | |
selevel string | Default: | The level part of the SELinux file context. This is the MLS/MCS attribute, sometimes known as the range .When set to _default , it will use the level portion of the policy if available. |
serole string | When set to _default , it will use the role portion of the policy if available. | |
setype string | When set to _default , it will use the type portion of the policy if available. | |
seuser string | By default it uses the system policy, where applicable.When set to _default , it will use the user portion of the policy if available. | |
size integer | Specifies the number of bits in the private key to create. For RSA keys, the minimum size is 1024 bits and the default is 4096 bits. Generally, 2048 bits is considered sufficient. DSA keys must be exactly 1024 bits as specified by FIPS 186-2. For ECDSA keys, size determines the key length by selecting from one of three elliptic curve sizes: 256, 384 or 521 bits. Attempting to use bit lengths other than these three values for ECDSA keys will cause this module to fail. Ed25519 keys have a fixed length and the size will be ignored. | |
state string |
| Whether the private and public keys should exist or not, taking action if the state is different from what is stated. |
type string |
| The algorithm used to generate the SSH private key. rsa1 is for protocol version 1. rsa1 is deprecated and may not be supported by every version of ssh-keygen. |
unsafe_writes boolean |
| Influence when to use atomic operation to prevent data corruption or inconsistent reads from the target file. By default this module uses atomic operations to prevent data corruption or inconsistent reads from the target files, but sometimes systems are configured or just broken in ways that prevent this. One example is docker mounted files, which cannot be updated atomically from inside the container and can only be written in an unsafe manner. This option allows Ansible to fall back to unsafe methods of updating files when atomic operations fail (however, it doesn't force Ansible to perform unsafe writes). IMPORTANT! Unsafe writes are subject to race conditions and can lead to data corruption. |
Common return values are documented here, the following are the fields unique to this module:
Key | Returned | Description |
---|---|---|
comment string | changed or success | Sample: |
filename | changed or success | Path to the generated SSH private key file /tmp/id_ssh_rsa |
fingerprint string | changed or success | Sample: SHA256:r4YCZxihVjedH2OlfjVGI6Y5xAYtdCwk8VxKyzVyYfM |
public_key string | changed or success | Sample: ssh-rsa AAAAB3Nza(...omitted...)veL4E3Xcw test_key |
size integer | changed or success | Sample: |
type | changed or success | Algorithm used to generate the SSH private key rsa |
![Generate ssh rsa key pair Generate ssh rsa key pair](/uploads/1/2/6/8/126891787/474709635.jpg)
- This module is not guaranteed to have a backwards compatible interface. [preview]
- This module is maintained by the Ansible Community. [community]
Authors¶
- David Kainz (@lolcube)
Hint
If you notice any issues in this documentation, you can edit this document to improve it.
Introduction
SSH (Secure Shell) allows secure remote connections between two systems. With this cryptographic protocol, you can manage machines, copy, or move files on a remote server via encrypted channels.
There are two ways to login onto a remote system over SSH – using password authentication or public key authentication (passwordless SSH login).
In this tutorial, you will find out how to set up and enable passwordless SSH login.
- Access to command line/terminal window
- User with sudo or root privileges
- A local server and a remote server
- SSH access to a remote server via command line/terminal window
You may already have an SSH key pair generated on your machine. To see whether you have SSH keys on the system, run the command:
If the output tells you there are no such files, move on to the next step, which shows you how to generate SSH keys.
In case you do have them, you can use the existing keys, back them up and create a new pair or overwrite it.
1. The first thing you need to do is generate an SSH key pair on the machine you are currently working on.
In this example, we generate a 4096-bit key pair. We also add an email address, however this is optional. The command is:
2. Next, type in the location where you want to store the keys or hit Enter to accept the default path.
3. It also asks you to set a passphrase. Although this makes the connection even more secure, it may interrupt when setting up automated processes. Therefore, you can type in a passphrase or just press Enter to skip this step.
4. The output then tells you where it stored the identification and public key and gives you the key fingerprint.
5. Verify you have successfully created the SSH key pair by running the command:
You should see the path of the identification key and the public key, as in the image below:
You can upload the public SSH key to a remote server with the
ssh-copy-id
command or the cat
command. Below you can find both options.Option 1: Upload Public Key Using the ssh-copy-id Command
To enable passwordless access, you need to upload a copy of the public key to the remote server.
1. Connect to the remote server and use the
ssh-copy-id
command:2. The public key is then automatically copied into the .ssh/authorized_keys file.
Another way to copy the public key to the server is by using the
cat
command.1. Start by connecting to the server and creating a .ssh directory on it.
2. Then, type in the password for the remote user.
3. Now you can upload the public key from the local machine to the remote server. The command also specifies that the key will be stored under the name authorized_keys in the newly created .ssh directory:
With the SSH key pair generated and the public key uploaded to the remote server, you should now be able to connect to your dedicated server without providing a password.
Generate Ssh Key Putty
Check whether the setup works by running the command:
The system should directly log you in to the remote server, no password required.
Note: Once you verify that you can SHH into the remote serve without a password, consider disabling SSH password authentication altogether. It will add another layer of security and secure your server from brute-force attacks.
Optional: Troubleshooting Remote Server File Permissions
File permissions on the remote server may cause issues with passwordless SSH login. This is a common issue with older versions of SSH.
If you are still prompted for a password after going through all the steps, start by editing file permissions on the remote server.
- Set permissions 700 for the .ssh directory.
- Set permissions 640 for the .ssh/authorized_keys directory.
Edit file permissions with the following command:
Enter your password when prompted. There will be no output if the action was successful. The issue should be resolved now.
If you want to automate updates and other tasks, or seamlessly SSH into a remote server, you should enable passwordless SSH login.
The instructions outlined in this article should have helped you to do so.
For more SSH commands, check out these 19 common SSH commands in Linux with examples.
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