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[HOWTO] Set/reset password of a VM by having cloud-init installed

Applies to:
  • VHI
  • VM
  • cloud-init

Symptoms:

By having a VM that has cloud-init installed within it, it is possible to automate the set/reset process by using Openstack

 

Resolution:

Procedure:

 1) Create or modify a "cloud-init.cfg" file to be used in desired VMs with the following content (in this example to change the password):

#cloud-config 
chpasswd: 
  list: | 
    root:<NEW_PASSWORD> 
  expire: False

 
2) Encoding it by using base64:

# base64 cloud-init.cfg

 
3) Once you have the base64-encoded string, you should use it as per the following Openstack command to apply it (could be using string or file path):
 
To create a new VM with a certain password:

# openstack --insecure server create --image <IMAGE_ID> --flavor <FLAVOR_ID> --user-data '<BASE64_ENCODED_STRING>' <INSTANCE_NAME>

or

# openstack --insecure server create --image <IMAGE_ID> --flavor <FLAVOR_ID> --user-data <USER_DATA_FILE> <INSTANCE_NAME>

 
For an existing VM:

# openstack --insecure server set --config-drive true --user-data '<BASE64_ENCODED_STRING>' <INSTANCE_NAME_OR_ID>

or

# openstack --insecure server set --config-drive true --user-data <USER_DATA_FILE> <INSTANCE_NAME_OR_ID>

 
* Remember that you could review all the complete options directly on the cloudinit page:
 
https://cloudinit.readthedocs.io/en/latest/tutorial/qemu.html#what-is-user-data
https://cloudinit.readthedocs.io/en/latest/tutorial/qemu.html#define-our-user-data
 

Optionally, If you have chosen to boot from a template or volume, which has cloud-init and OpenSSH installed:

Step 7 at: https://docs.virtuozzo.com/virtuozzo_hybrid_infrastructure_5_3_admins_guide/index.html#creating-virtual-machines.html

 

Related Ticket(s):

#406253

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