Boot a virtual machine with Huge Pages¶

This section explains how to boot a VM with Huge Pages.

To boot a virtual machine with Huge Pages:

1. Create a new flavor or use an existing one to use with Huge Pages. To create a new image flavor:

   . openrc admin admin
   nova flavor-create huge 999 1024 4 1
   

2. Add the size of huge pages to the image flavor:

   nova flavor-key huge set hw:mem_page_size=2048
   

3. Verify the image flavor exists:

   nova flavor-show huge
   

   Example of system response

   +----------------------------+------------------------------+
   | Property                   | Value                        |
   +----------------------------+------------------------------+
   | OS-FLV-DISABLED:disabled   | False                        |
   | OS-FLV-EXT-DATA:ephemeral  | 0                            |
   | disk                       | 4                            |
   | extra_specs                | {"hw:mem_page_size": "2048"} |
   | id                         | 7                            |
   | name                       | huge                         |
   | os-flavor-access:is_public | True                         |
   | ram                        | 1024                         |
   | rxtx_factor                | 1.0                          |
   | swap                       |                              |
   | vcpus                      | 1                            |
   +----------------------------+------------------------------+
   

4. Create a new image or use an existing image. You need an Ubuntu image and the default Cirros image.

   To create a new Ubuntu image:

   glance --os-image-api-version 1 image-create --name ubuntu \
      --location https://cloud-images.ubuntu.com/trusty/current/trusty-server-cloudimg-amd64-disk1.img \
      --disk-format qcow2 --container-format bare
   

5. Boot a new instance using the created flavor:

   nova boot --flavor huge --image ubuntu inst1
   

6. Verify that the new VM uses 512 huge pages:

   grep Huge /proc/meminfo
   

   Example of system response

   AnonHugePages:   1138688 kB
   HugePages_Total:    1024
   HugePages_Free:      512
   HugePages_Rsvd:        0
   HugePages_Surp:        0
   Hugepagesize:       2048 kB