Manage Virtual Server Administrative Options

Virtual Server administrative options include the list of actions that you can run as a VS administrator. 

To manage a virtual server administrative options:

  1. Go to your Control Panel > Cloud > Virtual Servers menu. 
  2. Click the label of the required virtual server.
  3. Click the Actions button on the VS's screen and then point to Administration to perform the following administrative actions on VSs:

Reset Root Password 

To reset a virtual server root password: 

  1. Click the Reset Root Password button.
  2. Turn the Set password switcher to the right and type your new password twice into the corresponding boxes.

      3. To enable the password encryption, turn the Encrypt password switcher to the right and type an encryption passphrase twice into the corresponding boxes.
      4. Click the Set Password button to save your new password. 

  • The virtual server will be rebooted after resetting the password.
  • Particular characters are not allowed for Windows-based virtual servers:
    • percent sign [%]
    • double quotation marks [“]
    • brackets [<,>]
    • vertical bar [|]
    • caret [^]
    • ampersand [&]
    • parentheses [(,)]

If you cannot reset the administrator password for a Windows-based virtual server via the UI:

  1. Connect to Control Panel via SSH:

    ssh root@CP_IP_ADDRESS
    su onapp

    Please note that port 22 should be open to proceed with the following steps.

  2. Connect to the Windows-based virtual server:

    • For 4.x templates:

    ssh -o StrictHostKeyChecking=no Administrator@VM_IP_ADDRESS

    Make sure that in Administrator is a capital letter.

    If a virtual server has a private IP address, make sure that CP has access to the virtual server network.

  3. At the command prompt, run:

  4. Change the administrator password (recommended to set the password in the UI):

    net user administrator newpassword

    In case this is a Windows-based virtual server with ADDS (Active Directory Domain Services) installed, run:

    net user administrator newpassword /domain
  5. Close the SSH connection.

Reboot is not required. Now you can log in normally with the password from the UI.

OnApp Cloud supports active directory domain controllers. The only limitation is that from the UI. OnApp cannot change or reset the password if the Windows virtual server is used as a domain controller.

Set Max Memory 

You can set a limit on RAM that can be allocated to virtual servers built on KVM compute resources. Setting the custom max memory limit is available for:

  • Virtual servers from KVM compute zones with the Ballooning release resource type and the Set max memory option enabled
  • Virtual servers that are built on templates that support Hot Resize
  • Users who have the Set Max Memory permission enabled in the Virtual Servers permissions set

To set a max memory limit for a virtual server: 

  1. Click the Set Max Memory button. 
  2. Move the Max Memory override slider to the right. 
  3. Enter the Max Memory limit in MB. 
  4. Click the Save button. 

After you save a max memory limit, reboot a virtual server to apply changes.

If you do not set the max memory limit for a virtual server but enable the Ballooning release resource type and the Set max memory option for a compute zone, the limit for VSs is calculated as follows: 

Max Memory Limit = Memory × Compute Resource Max Memory Rate 


  • Memory - the amount of RAM currently allocated to a virtual server
  • Compute Resource Max Memory Rate - the default max memory rate is eight (8)

    You can modify the default max memory rate (8) that is used to calculate a max memory limit. Change a value of the kvm_max_memory_rate parameter in the on_app.yml file.

The max memory limit for a virtual server is handled as follows: 

  • If the calculated max memory limit is more than 90% of free RAM available on a compute resource, then the limit is equal to 90% of free RAM available on the compute resource. 
  • If the calculated max memory limit is less than 90% of free RAM available on a compute resource, then the limit is equal to the calculated value.

    You can modify the default percentage (90%) that is used to calculate a max memory limit. Change a value of the kvm_available_free_memory_percentage parameter in the on_app.yml file.

Set Custom CPU Quota

  • To edit CPU Quota for a virtual server, you need to enable the default value for the compute resource first.
  • This feature is available only for KVM compute resources.

The default value of CPU quota can be customized according to your needs. You can overwrite the default value set for the compute resource for any particular virtual server you need. For example, if the default CPU quota for the compute resource is set to 50%, you can increase it to 90% depending on the priority of your virtual server.

To set custom value for the particular virtual server:

  1. Click the Set custom CPU Quota button.
  2. Move the CPU Quota enabled slider to the right to enable CPU quota to override the default value.
  3. Set CPU quota. The maximum value is 99%. Also, you can select the  checkbox to set an unlimited amount of CPU quota.  
  4. Click the Save button.

Custom CPU quota change can be done live without virtual server restart.

CPU Quota value can be changed automatically during migrating virtual server to another compute resource.

  • If migrating to the compute resource that does not have CPU Quota enabled, then CPU Quota value will be set to unlimited.
  • If migrating to the compute resource that has CPU Quota enabled, check the custom value for virtual server. Custom CPU quota will remain unchanged after the migration, while unspecified custom value will change into the default value. 

Change Owner 

To change an owner of a virtual server:

  1. Click the Change Owner button.
  2. In the dialog box, select a target user from the drop-down list that shows all users in the system.

  3. If you have any recipes or backups for this VS, you need to confirm if the recipe or the backup should be moved to another user. Select Yes if you want to make the recipes or backups of the virtual server available to the new owner. Otherwise, select No.

    If you select No, all the backups for this virtual server are deleted.

  4. Click the Change Owner button to grant ownership to the selected user. 
  • If you want to change an owner of the VS, which was built using an instance package, ensure that the new owner has permission to create VS using instance package and appropriate instance package in the bucket. Otherwise, you will not be able to change the ownership of this VS.
  • Note that you cannot change the ownership of a recipe which you do not own, even if it is assigned to your virtual server.

Set SSH Keys

  • This functionality is appicable to Linux-based VSs only.
  • The virtual server will be rebooted after setting SSH keys.
  • If a VS owner does not have any SSH keys, the system will only assign admin keys.
  • Note that if you have some customly added keys, they will be lost after setting SSH keys.

To set SSH keys for a virtual server: 

  1. Click the Set SSH keys button to assign SSH keys of the admin and a VS owner to the VS. 

  2. In the pop-up dialog box, click the Set SSH keys button to confirm the action. 


To edit FQDN (fully qualified domain name):

  1. Click the Edit FQDN button.
  2. In the pop-up dialog box, edit the hostname and the domain name. 
  3. Move the Force reboot slider to the right to enable FQDN update in case the transaction fails with a running virtual server.

    • If the Force reboot is disabled, the FQDN will be changed on the fly if possible. If it is not possible, the transaction will fail and the FQDN won't be changed.
    • If the Force option is enabled, you will see two more options, Shutdown type and Required startup.
  4. Select the shutdown type from the dropdown list (Gracefully shutdown or power off).

    • Gracefully shutdown - to run a graceful shutdown of VSs
    • Power Off - to run a forceful shutdown of VSs
  5. Tick the Required startup checkbox to start up the virtual server automatically after the FQDN is updated.  
  6. Click the Submit button.

If your OnApp version is older than 5.9, the hostname of a VS cannot be changed via the UI. You can change it by updating the hostname directly within the virtual_machines table of the OnApp database and manually within the VM itself.

mysql> update virtual_machines set hostname="<new_hostname>" where identifier="<vm_identifier>";

We suggest taking a dump of the OnApp database prior to making any manual changes as a precaution.