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Cloud - VM Parameters

In this article you will learn:

Preparing the VM for parameter changes

Make changes to the virtual machine parameters in the OpenNebula Sunstone interface. First, select the virtual machine using these steps:

  1. Log in to the ON Sunstone ⧉ interface.
  2. In the left menu, select Instances VMs.
  3. Select the virtual machine whose parameters you want to change.
Selecting a virtual machine in ON Sunstone
Selecting a virtual machine in ON Sunstone

Before changing parameters, make sure the machine is powered off:

  1. Click the power off button and select Power Off hard.
  2. Verify that the machine is in the POWEROFF state.
ON Sunstone - powering off a virtual machine
ON Sunstone – powering off a virtual machine

Changing CPU and RAM

You can increase or decrease both CPU and RAM for a VM. Perform the settings using these steps:

  1. In the VM controls, select the Capacity tab.
  2. Click the Resize button.
  3. In the window, set the required values.
  4. Confirm the settings with the Resize button in the window.
ON Sunstone - opening the CPU and RAM change window
ON Sunstone – opening the CPU and RAM change window

The interface allows you to allocate physical and virtual CPU:

  • Physical CPU corresponds to the actual number of hardware cores available to the VM. It also allows allocating fractions of cores (0.5).
  • Virtual CPU is the number of cores the VM uses.

By using different configurations of physical and virtual CPU, you can affect both the performance and the overall operation of the virtual machine.

Changing disk space

You can only increase disk space; decreasing it is not possible. If you need to reduce the virtual machine disk size, create a new VM and transfer the data to it. We do not perform migrations on our side.

Increase the disk space using these steps:

  1. In the VM controls, select the Storage tab.
  2. For the disk you want to increase, click the Resize icon.
  3. In the window, set the required value.
  4. Confirm the settings with the Resize button in the window.
ON Sunstone - opening the disk size change window
ON Sunstone – opening the disk size change window

If the increase is successful, you will see the new value in the Size column for the corresponding Image. This change should persist from the DISK_RESIZE state until POWEROFF. If the size returns to the original value, contact support via the form ⧉. Include the Cloud name and the specific VM.

After increasing the disk and powering on the VM, check that the change was applied correctly. In Linux, use the df -h command for this. If the change did not take effect in the system, power off the VM using Power Off (hard) and then power it on again. A restart is not enough.

Common issues

Common problems with changing cloud VM parameters include:

Inactive Resize button

Problem: The Resize button for changing CPU/RAM is not active.

Cause: The virtual machine is probably not powered off.

Solution: Power off the virtual machine and make sure it is in the POWEROFF state.

Disk shrink error

Problem: The following error appears: [one.vm.diskresize] New disk size has to be greater than current one.

Cause: You can only increase the disk size, not decrease it.

Solution: Create a new virtual machine with the required parameters.

CPU/RAM quota error

Problem: The following error appears: [one.vm.resize] User [****] : group [****] limit of X reached for MEMORY/CPU quota in VM.

Solution: Obtain more memory or CPU by limiting/canceling other VMs, or by increasing the total service capacity.

Parameter increase did not complete

Problem: The following error appears: Parameter increase did not complete.

Solution: Perform Undeploy (hard), then Deploy, and try increasing the parameters again.

Frequently asked questions

Can I change parameters this way also for the VPS ON service?

No, for the VPS ON service, follow this guide.

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