In this article you will learn:
- How to prepare a virtual machine for changing parameters
- How to change CPU and RAM
- How to change disk space
- Common problems
- Frequently Asked Questions
Preparing the VM for changing parameters
Change the virtual machine parameters in the OpenNebula Sunstone interface. First, select the virtual machine using these steps:
- Log in to the interface ON Sunstone ⧉.
- In the left menu, select Instances VMs.
- Select the virtual machine whose parameters you want to change.
Before changing the parameters, make sure the machine is powered off:
- Click the power off button and select Power Off hard.
- Verify that the machine is in the state POWEROFF.
Changing CPU and RAM
You can both increase and decrease the CPU and RAM of a VM. Follow these steps:
- In the VM controls, select the tab Capacity.
- Click the button Resize.
- In the window, set the required values.
- Confirm the settings with the button Resize in the window.
The interface lets you assign both physical and virtual CPUs:
- Physical CPU corresponds to the actual number of hardware cores available to the VM. It also lets you assign fractions of cores (0.5).
- Virtual CPU is the number of cores the VM counts on.
Different configurations of physical and virtual CPUs can affect the performance and 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 disk size of a virtual machine, 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:
- In the VM controls, select the tab Storage.
- For the disk you want to increase, click the icon Resize.
- In the window, set the required value.
- Confirm the settings with the button Resize in the window.
If the increase is successful, you will see the new value in the column Size for the corresponding Image. This change should persist from the state DISK_RESIZE until the state POWEROFF. If the size returns to the original value, contact Support via the form ⧉. Specify the name of the Cloud and the particular VM.
After increasing the disk, check once the VM is powered on that the change was applied correctly. On Linux, use the command df -h. If the change has not taken effect in the system, power off the VM via Power Off (hard) and power it on again. A restart is not enough.
Common problems
Common problems with changing the parameters of a cloud VM 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 state POWEROFF.
Disk shrinking error
Problem: An error is displayed: [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: An error is displayed: [one.vm.resize] User [****] : group [****] limit of X reached for MEMORY/CPU quota in VM.
Solution: Free up more memory or CPU, either by limiting/removing other VMs or by increasing the overall performance of the service.
Parameter increase failed
Problem: An error is displayed: The parameter increase failed.
Solution: Perform Undeploy (hard), then Deploy, and try to increase the parameters again.
Frequently Asked Questions
Can I change parameters this way for the VPS ON service too?