Ok, thanks. And one more: is it true that if I lost front-end host along with some hypervisor hosts died VMs don't restart on alive hosts?
On Thu, Sep 5, 2013 at 1:34 PM, Carlos Martín Sánchez < cmar...@opennebula.org> wrote: > Hi, > > On Wed, Sep 4, 2013 at 12:03 PM, Igor Laskovy <igor.lask...@gmail.com> > wrote: > >> One further question - how Fault Tolerance mechanism (via HOST_HOOK) deal >> with this reservations? Does it reserved some "slots" for VMs recovery? >> > > OpenNebula does not have any kind of reservation scheduling. > > >> If not and if I at every turn manually don't control available resources >> on hosts those may cause to situation when my automatically recreated VMs >> will stuck in placement state. >> > > Yes, that may happen. But you still can implement a reservation mechanism. > I'm sure there are better alternatives, but this is a quick idea: > > - Disable half of your hosts. > - For each enabled host, define a failover_host = <id> attribute in its > template, pointing to one of the disabled hosts > - Modify the fault tolerance hook to make it enable the defined failover > host. > > Another quick hack is to create a dummy VM for each VM that you need to > guarantee that reserved slot, using the requirements and current_vms > features to deploy it in a host different from the original VM. Then delete > that VM when the hook recreates the original VM... > > > Regards. > > -- > Join us at OpenNebulaConf2013 <http://opennebulaconf.com> in Berlin, > 24-26 September, 2013 > -- > Carlos Martín, MSc > Project Engineer > OpenNebula - The Open-source Solution for Data Center Virtualization > www.OpenNebula.org | cmar...@opennebula.org | > @OpenNebula<http://twitter.com/opennebula><cmar...@opennebula.org> > > > On Wed, Sep 4, 2013 at 12:03 PM, Igor Laskovy <igor.lask...@gmail.com>wrote: > >> Thank you for reply! >> >> One further question - how Fault Tolerance mechanism (via HOST_HOOK) deal >> with this reservations? Does it reserved some "slots" for VMs recovery? If >> not and if I at every turn manually don't control available resources on >> hosts those may cause to situation when my automatically recreated VMs will >> stuck in placement state. >> >> >> On Wed, Sep 4, 2013 at 12:23 PM, Carlos Martín Sánchez < >> cmar...@opennebula.org> wrote: >> >>> Hi, >>> >>> On Tue, Sep 3, 2013 at 1:32 PM, Igor Laskovy <igor.lask...@gmail.com>wrote: >>> >>>> Hello all! >>>> >>>> I found that this already have discussed not so far from now - >>>> http://comments.gmane.org/gmane.comp.distributed.opennebula.user/10568 >>>> >>>> As understand for now about Memory over-commitment for production I can >>>> forget ;) >>>> >>>> For CPU over-commitment I can only use CPU & VCPU attributes, right? >>>> >>> >>> That's right >>> >>> >>>> If I will, for example, set CPU to 0.2, than host will do only >>>> reservation of processor time for that VM OR do limit ether, so this VM >>>> will limited of 1/5 of one physical/logical hardware core? >>>> >>> >>> We enforce the CPU reserved at hypervisor level with cgroups for kvm, >>> credit scheduler for xen, and the esx cpu scheduler for vmware >>> >>> Regards >>> >>> -- >>> Join us at OpenNebulaConf2013 <http://opennebulaconf.com/> in Berlin, >>> 24-26 September, 2013 >>> -- >>> Carlos Martín, MSc >>> Project Engineer >>> OpenNebula - The Open-source Solution for Data Center Virtualization >>> www.OpenNebula.org <http://www.opennebula.org/> | cmar...@opennebula.org >>> | @OpenNebula <http://twitter.com/opennebula> >>> >> >> >> >> -- >> Igor Laskovy >> facebook.com/igor.laskovy >> studiogrizzly.com >> > > -- Igor Laskovy facebook.com/igor.laskovy studiogrizzly.com
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