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resize instance but insufficient vcpu

asked 2020-04-21 22:48:32 -0500

darkglobe gravatar image

updated 2020-04-21 22:49:12 -0500

Hello, I have a VM, running on a compute-1 with 20vCPU - 1 socket CPU.

compute-1 # lscpu | grep NUMA
NUMA node0 CPU(s):     0-19

from controller, I can see only 14vCPU available.

controller-1 # openstack hypervisor show 1 | grep -i "vcpus"
| vcpus                | 14   |
| vcpus_used           | 8  |

recently I have only one VM running in this compute, with flavor 8vCPU, 20GB memory, and 10GB Disk, with flavor properties: hw:cpu_policy='dedicated', hw:mem_page_size='1048576' .

I would like to resize the memory size of this VM, from 20GB to 30GB.

so I create a new flavor with exactly same flavor properties but Memory 30GB. then I shutdown the VM, and perform nova resize.

compute-1 # nova resize VM flavor_30G --poll
Server resizing... 0% complete
Error resizing server
ERROR (ResourceInErrorState):

but it does not works, it says:

“Insufficient compute resources: Requested instance NUMA topology cannot fit the given host NUMA topology”

I would like to know, why it is happening? and how to make this scenario works?

thank you

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1 answer

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answered 2020-04-22 13:12:10 -0500

updated 2020-04-22 13:12:56 -0500

Taken into consideration you have controller privileges to spawn instance,

When you do resize basically it create new Instance before deleting old one.

Resizing will spawn new instance with new flavour in different host. You need to have enough resources excluding old instance.

WA: if you resources available on same host where same instance sits Enable allow resizing on same host in nova.conf allow_resize_to_same_host = True

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Hi Piyushsrivastava, thx for the answr. mine is "allow_resize_to_same_host = True". So, the resize activity will only success if old+new resources instance <= total resources. am I correct here? what if my scenario VM-8vcpu-20gbRAM resize to VM-2vcpu-20gbRAM then to VM-8vcpu-30gb, will it works?

darkglobe gravatar imagedarkglobe ( 2020-04-22 13:55:58 -0500 )edit

yes if condition's satisfy old+new resources instance <= total resources yes

piyushsrivastava gravatar imagepiyushsrivastava ( 2020-04-24 02:21:43 -0500 )edit

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Asked: 2020-04-21 22:48:32 -0500

Seen: 222 times

Last updated: Apr 22 '20