[DOC] Add instruction for ssh key generation

OpenSSH 8.8+ disables the support for RSA/SHA1. For developers in this scenario uses "ssh-keygen -t rsa" command, the ssh key can be generated successfully. But it will come back" Permission Denied (Public Key)" when they try to pull/push code through ssh method. Few solutions in google will tell it could be the OpenSSH reason which may cause some time for trouble shooting. So instruction is added here.

Change-Id: Iaababa9e25e87604b1bc6464f65156ec6e6b2d31
Signed-off-by: qingshuting <qingshuting1@huawei.com>
Issue-ID: DOC-790

1 files changed, 19 insertions, 3 deletions

diff --git a/docs/guides/onap-developer/how-to-use-docs/setting-up-environment.rst b/docs/guides/onap-developer/how-to-use-docs/setting-up-environment.rst
index 6213afc24..e7d0a2f22 100644
--- a/docs/guides/onap-developer/how-to-use-docs/setting-up-environment.rst
+++ b/docs/guides/onap-developer/how-to-use-docs/setting-up-environment.rst
@@ -79,11 +79,27 @@ Setting SSH keys
 
 1. Generate SSH keys.
 
-.. code-block:: bash
+    For OpenSSH 8.7 or older versions:
+
+    .. code-block:: bash
+
+       ssh-keygen -t rsa
+
+    For OpenSSH 8.8 or later versions, either use ed25519 or ECDSA algorithm to generate ssh keys:
+
+    .. code-block:: bash
+
+        ssh-keygen -t ed25519
+
+    or
+
+    .. code-block:: bash
+
+        ssh-keygen -t ECDSA
 
-    ssh-keygen -t rsa
+    .. note:: OpenSSH 8.8+ disables RSA signatures using the SHA-1 hash algorithm by default, which may cause authentication problem when pull/push code. You can either specify the encrypt algorithm or re-enable the RSA/SHA1 in ~/.ssh/config file to solve the issue. For more information, please refer to `OpenSSH Release Notes <https://www.openssh.com/releasenotes.html>`_.
 
-Your public key is now available as .ssh/id_rsa.pub in your home folder.
+    Your public key is now available as .ssh/id_rsa.pub or .ssh/id_ed25519.pub or .ssh/id_ecdsa.pub under .ssh folder.
 
 2. Print the generated key to the terminal and copy it.