Excellent answer thank you sir. One doubt comes into my mind is for this reservation to work RAM over committing should be disabled? ie ram_allocation_ratio=1 Thanks for your help
On Thu, Nov 27, 2014 at 7:20 PM, Luis Fernandez Alvarez <[email protected]> wrote: > Hi, > > In general, you can see 'reserved_host_memory_mb' as your estimation of how > much memory your hypervisor needs. From the point of view of Nova, your > system is consuming the amount you set in 'reserved_host_memory_mb' [0]. > > Then, the field 'free_ram_mb' (the one that is checked when VMs are being > scheduled) is calculated using the memory consumed by the instances and the > value of reserved memory [1]. > > Said that, the scheduler won't see the real free mem (700Mb in your case), > it will see the calculated value. I would suggest you take a look to the > value of "free_ram_mb" on your hypervisor (the value in the database: like > "nova hypervisor-show", not the one in the compute logs), and then... you > compare. If you're expection 700Mb and you see 900Mb, you should tweak a bit > more your 1024Mb or reserved memory and increase it. > > It's a bit difficult to follow the flow in the code, but these links are > quite useful to understand how it works. > > [0] > https://github.com/openstack/nova/blob/master/nova/compute/resource_tracker.py#L695 > https://github.com/openstack/nova/blob/master/nova/compute/resource_tracker.py#L708 > [1] > https://github.com/openstack/nova/blob/master/nova/compute/resource_tracker.py#L532 > > > > On 11/27/2014 01:55 PM, mad Engineer wrote: >> >> it reports "Free ram (MB): 425" >> but free -m has different result. >> >> Is it working for you.Are you using icehouse >> >> On Thu, Nov 27, 2014 at 6:16 PM, George Mihaiescu <[email protected]> >> wrote: >>> >>> Then I would enable debug and verbose in nova.conf and restart the >>> scheduler >>> service. In this way you should see in the logs the entire scheduler >>> logic >>> and what resources it thinks your host has. >>> >>> On 27 Nov 2014 06:20, "mad Engineer" <[email protected]> wrote: >>>> >>>> George, >>>> overcommit of RAM is 1 and that is working.However >>>> instances are still getting created with available free memory < >>>> reserved_host_memory_mb >>>> >>>> On Thu, Nov 27, 2014 at 4:33 PM, George Mihaiescu <[email protected]> >>>> wrote: >>>>> >>>>> Depending on your overcommit ratio, the scheduler can schedule >>>>> instances >>>>> using more virtual memory than the available physical memory on the >>>>> host, >>>>> 700 MB in your case. >>>>> >>>>> On 27 Nov 2014 05:36, "mad Engineer" <[email protected]> wrote: >>>>>> >>>>>> hi all i have set >>>>>> reserved_host_memory_mb in nova.conf of controller and compute and >>>>>> restarted necessary services. >>>>>> i am expecting scheduler to not pickup host that has less than what is >>>>>> reserved_host_memory_mb >>>>>> in my example i put reserved_host_memory_mb = 1024 >>>>>> and free RAM in compute node is 700 Mb. >>>>>> But still scheduler chooses this host and created a new instance on >>>>>> it.I >>>>>> am expecting scheduler to show "No valid Hosts found" as it has less >>>>>> ram >>>>>> than reserved_host_memory_mb = 1024 >>>>>> >>>>>> Can some one help me understand this value >>>>>> >>>>>> Thanks >>>>>> >>>>>> _______________________________________________ >>>>>> Mailing list: >>>>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack >>>>>> Post to : [email protected] >>>>>> Unsubscribe : >>>>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack >>>>>> >> _______________________________________________ >> Mailing list: >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack >> Post to : [email protected] >> Unsubscribe : >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack > > > > _______________________________________________ > Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack > Post to : [email protected] > Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack _______________________________________________ Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack Post to : [email protected] Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
