Open Stack

On Thu, 2021-12-02 at 08:58 +0530, open infra wrote:
> Hi,
> 
> I have created a flavor with following properties and created an instance.
> Instance failed with the error "No valid host was found. There are not
> enough hosts available."
> When I set the cpu policy as 'shared' I can create the instance.  The host
> machine has two numa nodes and a total of 128 vcpu.
> I can not figure out what's missing here.
i suspect the issue is not with the flavor but with yoru host configurtion.

you likely need to defience cpu_dedicated_set and cpu_shared_set in the nova.conf

we do not support mixing pinned and floating cpus on the same host unless you partion the cpu pool
using cpu_dedicated_set and cpu_shared_set.

as of train cpu_dedicated_set replaced vcpu_pin_set as the supported way to report the pool of cpus to be
used for pinned vms to placment.

if you do "openstack resource provider inventory show <compute node uuid>" it should detail the avaiabel pcpu and vcpu inventories.
when you use  hw:cpu_policy='dedicated' it will claim PCPUs not VCPUs in placment.
That is likely the issue you are encountering.

by default we have a fallback query to make this work while you are upgrading

https://docs.openstack.org/nova/latest/configuration/config.html#workarounds.disable_fallback_pcpu_query

which we should be disabling by default soon.

but i suspect that is likely why you are getting the no valid host.

to debug this properly you should enable debug logging on the nova schduler and then confirm if you got
host back form placment and then if the numa toplogy filter is rejectign the host or not.

without the schduler debug logs for the instance creation we cannt really help more then this since we do not have the info required.
> 
> controller-1:~$ openstack flavor show dn.large -c properties
> 
> +------------+--------------------------------------------------------------------------------------------------------+
> 
> > Field      | Value
>                                           |
> 
> +------------+--------------------------------------------------------------------------------------------------------+
> 
> > properties | hw:cpu_cores='2', hw:cpu_policy='dedicated',
> hw:cpu_sockets='1', hw:cpu_threads='2', hw:numa_nodes='1' |
> 
> +------------+--------------------------------------------------------------------------------------------------------+
> 
> controller-1:~$ openstack hypervisor stats show
> 
> +----------------------+--------+
> 
> > Field                | Value  |
> 
> +----------------------+--------+
> 
> > count                | 1      |
> 
> > current_workload     | 0      |
> 
> > disk_available_least | 187    |
> 
> > free_disk_gb         | 199    |
> 
> > free_ram_mb          | 308787 |
> 
> > local_gb             | 219    |
> 
> > local_gb_used        | 20     |
> 
> > memory_mb            | 515443 |
> 
> > memory_mb_used       | 206656 |
> 
> > running_vms          | 7      |
> 
> > vcpus                | 126    |
> 
> > vcpus_used           | 49     |
> 
> +----------------------+--------+
> 
> 
> 
> Regards,
> 
> Danishka