Installation and configuration of cloud-init on the Linux server

IBM® Cloud Infrastructure Center uses cloud-init as its activation engine. It works well with cloud-init 18.2 for RHEL7.6 and cloud-init 18.5 for RHEL7.7.

If you are using a different version of cloud-init, you should change your specification of the indicated commands.

During cloud-init installation, some dependency packages might be required. You can use yum to easily resolve these dependencies.

Follow the below steps to install and configure cloud-init service.

Ssh to the Linux® server, issue the following to install cloud-init:
```
yum install cloud-init    
```
IBM Cloud Infrastructure Center uses ConfigDrive as the data source during the installation process. Remember to disable network configuration because network configuration is done by zvmguestconfigure.

You must add the following lines to the default configuration file /etc/cloud/cloud.cfg:
```
datasource_list: [ ConfigDrive, None ]
datasource:
      ConfigDrive:
        dsmode: local
network: {config: disabled}
```
Note: Pay attention to the indentation, otherwise, cloud-init might not work as expected.
Optionally, the default /etc/cloud/cloud.cfg file supports login by ssh key. If you want to log in by user name and password via ssh, configure the /etc/cloud/cloud.cfg file by the command:
```
ssh_pwauth：1
```
Optionally, to enable root login, you can configure the /etc/cloud/cloud.cfg file by the command:
```
disable_root: false
```

Enable and start the cloud-init related services by issuing the following commands:

systemctl enable cloud-init-local.service
systemctl start cloud-init-local.service
systemctl enable cloud-init.service
systemctl start cloud-init.service
systemctl enable cloud-config.service
systemctl start cloud-config.service
systemctl enable cloud-final.service
systemctl start cloud-final.service

If you experience problems the first time you start cloud-config.service and cloud-final.service, try to start them again.

Ensure all cloud-init services are in active status by issuing the following commands:

systemctl status cloud-init-local.service
systemctl status cloud-init.service
systemctl status cloud-config.service
systemctl status cloud-final.service

To verify cloud-init configuration, issue the following command. If no errors occur, cloud-init is installed correctly.
```
cloud-init init --local
```
Remove the /var/lib/cloud directory (if it exists) so that cloud-init does not run after a restart:
```
rm -rf /var/lib/cloud
```