Manual Chapter : CPU Core Upgrade for Deployed Guests

Applies To:

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BIG-IP DNS

  • 15.0.1, 15.0.0, 14.1.2, 14.1.0, 14.0.0

BIG-IP ASM

  • 15.0.1, 15.0.0, 14.1.2, 14.1.0, 14.0.0

BIG-IP AAM

  • 14.1.2, 14.1.0, 14.0.0

BIG-IP APM

  • 15.0.1, 15.0.0, 14.1.2, 14.1.0, 14.0.0

BIG-IP LTM

  • 15.0.1, 15.0.0, 14.1.2, 14.1.0, 14.0.0
Manual Chapter

CPU Core Upgrade for Deployed Guests

About increasing CPU cores for a deployed guest

Overview

If you have a guest that's actively processing application traffic but needs additional CPU cores, you can increase the number of cores that are currently allocated to the guest. To do this, you'll need to temporarily disable the guest while you add cores, and then re-deploy the guest.

About CPU core availability

When you increase the Cores per Guest value on a guest, the new value must be within the total number of unused CPU cores on the system; the system never allocates more cores to a guest than the number of cores still available on the system.

For example, suppose you have three guests on a 12-core system, with this core allocation:

Guest Name Current Cores per Guest
Guest A 6
Guest B 2
Guest C 2

With a total allocation of 10 out of 12 cores allocated on the system, this means that only two cores remain unused and available to add to a guest. Therefore, if you try to add four additional cores to Guest C (from 2 to 6), the system displays a message that you are exceeding the number of cores available on the system. In this case, the total number of cores that you can allocate to Guest C is 4.

A potential workaround for this would be to first decrease the number of cores allocated to Guest A, to free up additional cores for Guest C.

You can determine the number of cores still available on the system by logging in to the BIG-IP Configuration utility and displaying the vCMP Guest List screen.

Increasing CPU cores for a deployed guest

Before doing this task, confirm that your BIG-IP user account has an Administrator role assigned to it.

If you have a deployed vCMP guest, and you decide that you need to allocate more CPU cores per slot to the guest than you had originally allocated, you can increase the number of cores per slot for the guest.

To do this, you'll first need to set the guest state from Deployed to Configured. Once you've increased the number of cores per slot for the guest, you can set the guest back to the Deployed state.

Note that when switching between guest states, the process can take several minutes for the guest to shut down cleanly and restart again.

Important: When you set a guest to the Configured state, the guest is removed from service until you set the guest back to the Deployed state.
  1. Log in to the BIG-IP Configuration utility on the vCMP host, using the VIPRION system's primary management IP address.
  2. On the Main tab, click vCMP > Guest List .
  3. View the graphic to determine the number of unused cores available on the slot.
    This tells you how many cores are available to add to the guest.
  4. In the Name column, find the name of the guest that needs additional CPU cores and confirm that the Requested State is Deployed.
  5. To the left of the guest name, select the check box.
  6. Click the Disable button.
    The guest state changes from Deployed to Configured.
    Important: It might take a few minutes for the guest state to change to Configured. Although the Guest List screen does not display a progress indicator during this state change, you can log into the console and view the status of the guest at any time, using the command tmsh show vcmp guest.
  7. Once the screen shows that the guest is now in the Configured state, click the guest name.
    The guest properties screen opens.
  8. From the Cores per Slot list, select a higher number of CPU cores.
    Note: Do not select a value that exceeds the total number of unused cores available for use on the slot.
    For example, if you currently have two cores per slot allocated to the guest and you want to add two cores, then from the Cores per Slot list, select 4.
  9. From the Requested State list, select Deployed.
  10. Click Update.
    The Guest List screen opens again and you will see that the guest state is changing.
    Important: It might take a few minutes for the guest state to change back to the Deployed state. During the state change, the system displays a progress indicator.
After you complete this task, the guest has additional CPU cores per slot and is capable of processing application traffic.