Cloud-Init 0.7.9 or later

Add the following key-value pair with an empty line above and below it:
```
no_ssh_fingerprints: true
```
Set ssh_pwauth to false or 0, indicating that password login in SSH mode is disabled.
```
ssh_pwauth: false
```
Set disable_root to false. This parameter specifies whether to allow SSH login of user root.
```
disable_root: true
```
Add preserve_hostname: false.
```
preserve_hostname: false
```
(Optional) Use the number sign (#) to comment out the following statements (skip this step if the statements do not exist):
```
mount_default_fields: [~, ~, 'auto', 'defaults,nofail', '0', '2']
resize_rootfs_tmp: /dev
ssh_deletekeys:   0
```
Modify ssh_genkeytypes as follows (add it if it does not exist):
```
ssh_genkeytypes: ['rsa', 'dsa']
```
Modify syslog_fix_perms as follows (add it if it does not exist):
```
syslog_fix_perms: root:root
```

Add the following statements:

network:
   config: disabled
datasource_list: [ OpenStack ]
datasource:
  OpenStack:
    metadata_urls: ['http://169.254.169.254']
    max_wait: 120
    timeout: 10
    retries: 5

(Optional) In /etc/cloud/cloud.cfg, set apply_network_config to False.
This step is only for Cloud-Init 18.3 or later.
Add the following content after - final-message in cloud_final_modules:
```
- power-state-change
```

Modify system_info as follows:

system_info:
   distro: rhel
   default_user:
      name: linux  //Username for OS login
      lock_passwd: True   //True indicates that login using a password is disabled. Note that some OSs use value 1 to disable the password login.

In the preceding command, change the value of distro based on the OS, such as distro: sles, distro: rhel, distro: ubuntu, distro: debian, and dustro: fedora.

(Optional) For SUSE 12 SP1 and SUSE 12 SP2, modify [Unit] in the /usr/lib/systemd/system/cloud-init-local.service file.

vi /usr/lib/systemd/system/cloud-init-local.service

Ensure that [Unit] is configured as follows:

[Unit]
Description=Initial cloud-init job (pre-networking)
DefaultDependencies=no
Wants=network-pre.target
Wants=local-fs.target
After=local-fs.target
Before=network-pre.target
Before=shutdown.target
Before=basic.target
Conflicts=shutdown.target
# Other distros use Before=sysinit.target. There is not a clearly identified
# reason for usage of basic.target instead.

(Optional) For Ubuntu 16.04, run the following command to configure the OpenStack source:
dpkg-reconfigure cloud-init

Run the vim /etc/cloud/cloud.cfg.d/90_dpkg.cfg command to open the configuration file and check whether the items are correctly configured in the file.
```
# to update this file, run dpkg-reconfigure cloud-init
datasource_list: [ OpenStack ]
~
~
~
```
If the configuration file content is consistent with the preceding command output, the configuration is successful.