How to use pre-created ssh key for overcloud or replace a security key in OpenStack Platform?

Issue

• I would like to use pre-created ssh key to overcloud.
• Can not ssh to overcloud nodes
• overcloud ssh
• ssh overcloud fails
  If the stack user ssh pub key does not match the default key imported in nova, ssh auth will fail. In that case ssh heat-admin@overcloud_node_ip will ask for a password (since there is no valid ssh key configured).

In order to check, please execute either openstack keypair show default --public-key or nova keypair-show default and compare the key with the stack user public key (cat /home/stack/.ssh/id_rsa.pub). If they mismatch, the nova key in the undercloud should be replaced with the stack user's id_rsa.pub.

In the following output all keys match, i.e. are configured correctly:

[stack@undercloud ~]$ openstack keypair show default --public-key
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCeWqcePhDoTOjin/gzUqhQYM+xwROF8qsyTiIzF9egw3A+W6+7dwr2L2Ob89jA3v+KU2vaAkdzMxNw8E/Ra7AJWCEWG0eYqZdP34EOn7aMtG+I7ZV7cG2uC4u+z7c+jNS7idUZ3PRMRE/dVAEShxJTnLUOvVSq0SqYQZAgo7BK3LH/A81Vcxbjm8OTbdBMRqqnrdzmGppcowosE6DnwDqzCTk0y+Bf4rZ3P0JHT1lK+jZcVbQq9A12oxSwlUolXsjQUWfpBCITakuGPCli6yx/gqBRd/kk3TZrZGSHTrD5VmXhBhSl2Exu0fhrmSsz8G8Y6TYJst+syjLty9qJ0zuj stack@undercloud.default.redhat.local

[stack@undercloud ~]$ nova keypair-show default
+-------------+-------------------------------------------------+
| Property    | Value                                           |
+-------------+-------------------------------------------------+
| created_at  | 2016-10-10T07:51:01.000000                      |
| deleted     | False                                           |
| deleted_at  | -                                               |
| fingerprint | d9:d8:31:1a:e8:85:43:a7:bd:f2:c1:69:51:4d:ad:a9 |
| id          | 3                                               |
| name        | default                                         |
| updated_at  | -                                               |
| user_id     | 88951ae9bafe4aedbe248fd623caae8c                |
+-------------+-------------------------------------------------+
Public key: ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCeWqcePhDoTOjin/gzUqhQYM+xwROF8qsyTiIzF9egw3A+W6+7dwr2L2Ob89jA3v+KU2vaAkdzMxNw8E/Ra7AJWCEWG0eYqZdP34EOn7aMtG+I7ZV7cG2uC4u+z7c+jNS7idUZ3PRMRE/dVAEShxJTnLUOvVSq0SqYQZAgo7BK3LH/A81Vcxbjm8OTbdBMRqqnrdzmGppcowosE6DnwDqzCTk0y+Bf4rZ3P0JHT1lK+jZcVbQq9A12oxSwlUolXsjQUWfpBCITakuGPCli6yx/gqBRd/kk3TZrZGSHTrD5VmXhBhSl2Exu0fhrmSsz8G8Y6TYJst+syjLty9qJ0zuj stack@undercloud.default.redhat.local

[stack@undercloud ~]$ cat /home/stack/.ssh/id_rsa.pub 
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCeWqcePhDoTOjin/gzUqhQYM+xwROF8qsyTiIzF9egw3A+W6+7dwr2L2Ob89jA3v+KU2vaAkdzMxNw8E/Ra7AJWCEWG0eYqZdP34EOn7aMtG+I7ZV7cG2uC4u+z7c+jNS7idUZ3PRMRE/dVAEShxJTnLUOvVSq0SqYQZAgo7BK3LH/A81Vcxbjm8OTbdBMRqqnrdzmGppcowosE6DnwDqzCTk0y+Bf4rZ3P0JHT1lK+jZcVbQq9A12oxSwlUolXsjQUWfpBCITakuGPCli6yx/gqBRd/kk3TZrZGSHTrD5VmXhBhSl2Exu0fhrmSsz8G8Y6TYJst+syjLty9qJ0zuj stack@undercloud.default.redhat.local
[stack@undercloud ~]$