Re: [Users] RFE: A manual way of saying that only hostA in a DC shall be used as proxy for power commands

30 jul 2012 kl. 12.26 skrev Itamar Heim: > On 07/30/2012 12:03 PM, Karli Sjöberg wrote: >> >> 30 jul 2012 kl. 11.01 skrev Itamar Heim: >> >>> On 07/30/2012 08:56 AM, Karli Sjöberg wrote: >>>> >>>> 28 jul 2012 kl. 14.11 skrev Moti Asayag: >>>> >>>>> On 07/26/2012 02:53 PM, Karli Sjöberg wrote: >>>>>> Hi, >>>>>> >>>>>> In my DC, I have three hosts added: >>>>>> >>>>>> hostA >>>>>> hostB >>>>>> hostC >>>>>> >>>>>> I want a way to force only to use hostA as a proxy for power >>>>>> commands. >>>>> >>>>> The algorithm of selection a host to act as a proxy for PM commands is >>>>> quite naive: any host from the system with status UP. >>>>> >>>>> You can see how it is being selected in >>>>> FencingExecutor.FindVdsToFence() >>>>> from >>>>> ovirt-engine/backend/manager/modules/bll/src/main/java/org/ovirt/engine/core/bll/FencingExecutor.java >>>>> >>>>> There is no other algorithm for the selection at the moment. >>>>> >>>>> How would you handle a case in which hostA isn't responsive ? Wouldn't >>>>> you prefer trying to perform the fencing using other available host ? >>>> >>>> >>>> Let me explain a little to make you better understand my reasoning >>>> behind this configuration. >>>> >>>> We work with segmented, separated networks. One network for public >>>> access, one for storage traffic, one for management and so on. That >>>> means that if the nodes themselves have to do their own >>>> power-management, the nodes would require three interfaces each, >>>> and the >>>> metal we are using for hosts just don´t have that. But if we can >>>> use the >>>> engine to do that, the hosts would only require two interfaces, which >>>> most 1U servers are equipped with as standard (plus one >>>> iLO/IPMI/whatev), so we can use them as hosts without issue. Then the >>>> backend has one extra interface that it can use to communicate over the >>>> power management network to the respective service processor with. >>>> >>>> Is there a "better" way to achieve what we are aiming for? Ideally, I >>>> would like to set up the two NICs in a bond and create VLAN-interfaces >>>> on top of that bond. That way, I can have as many virtual interfaces as >>>> I want without having more than two physical NICs, but I haven´t been >>>> able to find a good HOWTO explaining the process. >>>> >>> >>> I think there is a difference between: >>> 1. allowing engine to fence >>> 2. allowing to choose fencing host per cluster (or per host) >>> >>> it sounds like you actually want #1, but can live with #2, by installing >>> the engine as a host as well. >> >> Exactly, I can live with #2, as I have the engine added as hostA in my DC > > well, the question is if choosing another host to use for fencing > would/should be limited to hosts from same DC, then engine can only be > used to fence one DC. I´m quoting you here: "1. power management is DC wide, not cluster." So this wouldn´t be any different from it´s current state.

> also, for any host other than engine, question is what to do if it is > down... Med Vänliga Hälsningar ------------------------------------------------------------------------------- Karli Sjöberg Swedish University of Agricultural Sciences Box 7079 (Visiting Address Kronåsvägen 8) S-750 07 Uppsala, Sweden Phone: +46-(0)18-67 15 66 karli.sjoberg(a)slu.se <mailto:karli.sjoberg@adm.slu.se>