nova hypervisor-stats or Horizon hypervisor summary show incorrect ram usage

asked 2017-04-11 08:21:15 -0500

Simone Cesar gravatar image

Hi all,

I've a problem with the resource usage summary, below you can see the output of "nova hypervisor-stats" command:

stack@helion-cp1-c1-m1-mgmt:~$ nova hypervisor-stats
+----------------------+-------+
| Property             | Value |
+----------------------+-------+
| count                | 2     |
| current_workload     | 0     |
| disk_available_least | 404   |
| free_disk_gb         | 440   |
| free_ram_mb          | 41830 |
| local_gb             | 934   |
| local_gb_used        | 494   |
| memory_mb            | 63846 |
| memory_mb_used       | 22016 |
| running_vms          | 16    |
| vcpus                | 16    |
| vcpus_used           | 16    |
+----------------------+-------+

https://drive.google.com/open?id=0BzM62wP8w3kVQk9FY01lNDF2dUk (horizon hypervisor summary)

Below the output of "free -mh", the real RAM usage, launched on the computes node.

compute1:

             total       used       free     shared    buffers     cached
Mem:           31G        21G       9.7G       665M       409M        15G
-/+ buffers/cache:       5.6G        25G
Swap:           0B         0B         0B

compute2:

             total       used       free     shared    buffers     cached
Mem:           31G        19G        11G       665M       397M        14G
-/+ buffers/cache:       4.4G        26G
Swap:           0B         0B         0B

From these outputs you can note that the memory_mb_used value (22GB)(the amount of ram used by all istances) is not equal to the sum of used mem values returned with the free command launched in the both compute nodes (21GB + 19GB = 40.7GB). This causes the failure of creation of an instalce when the used flavor RAM is greater then the free RAM but less then the free_ram_mb returned with the command "nova hypervisor-stats" Why the we've this discrepancy? How can I correct or aling these values?

thanks

Simone

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