-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Khder,
VCL knows about the specs (RAM, cores, processor speed) of each VM host and the specs of each image. It does not assign a reservation to a VM on a host that would result in the host's RAM being overbooked. The number of cores are not currently checked. So, they could be overbooked. Functionality to limit reservations based on number of cores will be added at a future date. So, yes, it is the responsibility of the hypervisor to assign the required resources, but it should never have to overbook the RAM to bring up a VM for a new reservation. For bare metal reservations, an image is never assigned to a node that doesn't meet the minimum specs of the image. Multiple users can make reservations for the same image. A separate node is deployed for every reservation. There could be a slight impact on deploy time since VCL uses linked clones for the disk files. So, reads for the same image would be hitting the same file. Write would be going to separate files. This is actually somewhat complicated because the base file on which the linked clones is actually only shared with hosts that are using the same datastore. When a node is already loaded with an image someone requests (we call this a hot standby node), the deploy time is obviously much shorter. VCL does not allow nodes to be shared other than the case of a bare metal machine running a hypervisor and hosting VMs (the VMs aren't shared, but the physical machine is). So, only one user would get a given preloaded node. Josh On Thursday, November 06, 2014 2:46:59 AM Khder Omar wrote: > Dear Josh, > > Thanks again for your reply ! I understand the mapping part ! Concerning > the VCL model as you might mentioned the terms could be different comparing > to a typical IaaS. > Most probably I was bit confusing the images provisioning. If I understood > it correctly, once reservation process starts, a new image will be deployed > in the corresponding computer or host [just streaming the disk images files > to build a complete environment within specific resources CPU and RAM] > > Therefore, that will be the Physical/Virtual deployer [Hypervisor] role to > assign those resources ? > > Another interesting point which highlights the point if many users can make > more than one reservation for the same image ? does it affect the image > loading time [queue of requests to access/use shared resource] ? besides, > if the image is already deployed and running in a specific computer [can be > physical/virtual], can many users access the same computer at the same time > ? > > Thanks for your clarification ! > > Best regards, > Phd Team > > 2014-11-05 22:34 GMT+01:00 Josh Thompson <[email protected]>: > > -----BEGIN PGP SIGNED MESSAGE----- > > Hash: SHA1 > > > > Khder, > > > > Mapping is just a way for the scheduler part of the frontend to know what > > computers a given image can be loaded on.This could be because of an > > architectural restriction or it could simply be because a researcher > > bought > > her own hardware and only her images should be run on them. Mapping > > doesn't > > actually have to do with where the image files reside. I don't think the > > backend code ever even looks at the mapping information. > > > > Remember that VCL predates the terms cloud computing, IaaS, PaaS, etc. > > So, > > the terms used for VCL might be somewhat different from more recent > > systems. > > > > In VCL, each "image" or "environment" consists of a set of disk image > > files > > and the associated information about the image that is in the database. > > Initial "base images" must be created somewhat manually. Then, further > > images > > are derived from those base images. I don't know that VCL really has > > flavors > > because each image will have its own CPU and RAM specifications. > > > > Does that answer your questions? > > > > Josh > > > > On Tuesday, November 04, 2014 11:00:01 PM Khder Omar wrote: > > > Dear Josh, > > > > > > I was wondering during the creation of new image, it does not require to > > > > be > > > > > stored in the computer node itself, it can be stored in an image library > > > like a SAN or NAS storage then we mapped a given image to a certain > > > computer or computer group ! the fact to 'map' an image or image group > > > > to a > > > > > computer or computer group, does it mean 'streaming' the image 'locally' > > > > to > > > > > the computer node ? or only during the reservation ? > > > I was bit confused between the terms used in VCL and in a typical IaaS > > > environment: the image is claimed as a template of a virtual machine, in > > > VCL, I have noticed that the image is being created from a base OS and > > > resources information are assigned in the database such as RAM, CPU, > > > > arch, > > > > > id etc... > > > Then I might assume [correct me if I understood it wrong] the Virtual > > > Machine will be initiated [considering an Hypervisor KVM or ESXi ] while > > > processing the reservation. Therefore, we can describe such image in a > > > typical IaaS as a virtual machine flavor ready to be deployed and run on > > > Host or Computer [within an hypervisor supported]. > > > > > > Thanks! > > > > > > PhD team > > > > > > 2014-10-30 20:07 GMT+01:00 Khder Omar <[email protected]>: > > > > Dear Josh, > > > > > > > > That is true ! Thanks again for the clarification ! I will start > > > > doing > > > > > > some experiments and see what it gives from performance perspective ! > > > > In > > > > > > the other hand, I will keep updating for any proposal of ideas can be > > > > generated then we can refine the scheduler code and retest again ! > > > > > > > > Many thanks for sharing such valuable information! > > > > > > > > We will keep updated ! > > > > > > > > Best Regards > > > > PhD Team > > > > > > > > 2014-10-30 19:56 GMT+01:00 Josh Thompson <[email protected]>: > > > >> -----BEGIN PGP SIGNED MESSAGE----- > > > >> Hash: SHA1 > > > >> > > > >> Khder, > > > >> > > > >> The scheduler only allocates a computer randomly if > > > >> SCHEDULER_ALLOCATE_RANDOM_COMPUTER is set to 1 in conf.php, which it > > > > is > > > > > >> not by > > > >> default. > > > >> > > > >> Yes, you could create pools that each have a weight or ranking > > > > assigned. > > > > > >> Each > > > >> computer would be assigned to a pool. Then, when the initial set of > > > >> computers > > > >> is generated, they could be ranked by the pool weight/ranks. It > > > >> would > > > >> then be > > > >> up to an administer or external application to manage the weight/rank > > > > of > > > > > >> each > > > >> pool. > > > >> > > > >> Josh > > > >> > > > >> On Thursday, October 30, 2014 7:48:50 PM Khder Omar wrote: > > > >> > Dear Josh, > > > >> > > > > >> > I would like to thank you for the precious hints concerning the > > > >> > > > >> scheduling > > > >> > > > >> > nature within VCL. I can see that the set of computers is filtered > > > > in > > > > > >> > advance and then the scheduler will pick up RANDOMLY one of them. > > > >> > To > > > >> > > > >> check > > > >> > > > >> > the possibilities to extend the function considering a large scale > > > >> > environment where we can introduce the 'region' or 'pool' term in > > > > the > > > > > >> code. > > > >> > > > >> > With multiple management nodes, do you think that using the > > > >> > 'weight' > > > >> > for > > > >> > the workload per pool and then per computer therefore will rank it > > > > will > > > > > >> be > > > >> > > > >> > more precise on how to balance the load across the hole > > > > infrastructure > > > > > >> > ? > > > >> > > > > >> > Best Regards, > > > >> > PhD team > > > >> > > > > >> > 2014-10-30 19:28 GMT+01:00 Josh Thompson <[email protected]>: > > > >> > > -----BEGIN PGP SIGNED MESSAGE----- > > > >> > > Hash: SHA1 > > > >> > > > > > >> > > Khder, > > > >> > > > > > >> > > Sorry for the late response. > > > >> > > > > > >> > > You can certainly experiment with extending the code to include > > > > more > > > > > >> > > advanced > > > >> > > scheduling functions. The existing ranking of computers is > > > > something > > > > > >> like > > > >> > > > >> > > this: > > > >> > > > > > >> > > 1) generate a set of all computers meeting the minimum > > > > requirements > > > > > >> of the > > > >> > > > >> > > image, that the user has access to, and that the image is mapped > > > > to; > > > > > >> order > > > >> > > > >> > > that list by node specs from low to high > > > >> > > 2) remove from that set any computers that are already assigned > > > >> > > reservations > > > >> > > 3) if the image is virtual, remove any VMs for which the host > > > > doesn't > > > > > >> have > > > >> > > > >> > > enough memory to load the VM (without overbooking) > > > >> > > 4) assign the new reservation the first computer from that set > > > >> > > for > > > >> > > > >> which > > > >> > > > >> > > an > > > >> > > active management node can be found > > > >> > > > > > >> > > There's actually 3 sets of computers being tracked - those > > > >> > > already > > > >> > > > >> loaded > > > >> > > > >> > > with > > > >> > > the image being requested, those set aside for a block allocation > > > > of > > > > > >> which > > > >> > > > >> > > the > > > >> > > user is a member, and then a set of both of those plus any > > > > available > > > > > >> > > computers > > > >> > > that are currently loaded with another image. > > > >> > > > > > >> > > There is a configuration option > > > > (SCHEDULER_ALLOCATE_RANDOM_COMPUTER) > > > > > >> in > > > >> > > > >> > > conf.php that allows the sets of computers to be randomized. The > > > >> > > motivation > > > >> > > behind this option is for sites that have homogeneous virtual > > > >> > > > >> machines and > > > >> > > > >> > > hosts. Randomizing the assigned computer should help spread the > > > > load > > > > > >> > > equally > > > >> > > among all existing hosts. > > > >> > > > > > >> > > I hope that helps. > > > >> > > > > > >> > > Josh > > > >> > > > > > >> > > On Tuesday, October 21, 2014 9:01:17 PM Khder Omar wrote: > > > >> > > > Hi Josh, > > > >> > > > > > > >> > > > Thanks for your reaction. I have checked the code source and I > > > >> > > > >> think the > > > >> > > > >> > > > only function which might fulfill my question is function > > > >> > > > > > >> > > allocComputer(...) > > > >> > > > > > >> > > > Eventually, the function a piece test schedule code > > > >> > > > > > > >> > > > if(SCHEDULER_ALLOCATE_RANDOM_COMPUTER) { > > > >> > > > > > > >> > > > shuffle($blockids); > > > >> > > > shuffle($currentids); > > > >> > > > shuffle($computerids); > > > >> > > > > > > >> > > > } > > > >> > > > > > > >> > > > > > > >> > > > I might assume if it was correctly understood that VCL > > > >> > > > scheduler > > > >> > > > >> process > > > >> > > > >> > > > determines in first place a computer to be assigned to a > > > > management > > > > > >> node > > > >> > > > >> > > > from a given array or table in order otherwise it can be > > > > randomly > > > > > >> > > > chosen! > > > >> > > > Then, we can assume that the scheduling decision is still using > > > > a > > > > > >> basic > > > >> > > > >> > > > order as FCFS or a chance/Random order! It that assumed be > > > > correct > > > > > >> ? if > > > >> > > > >> > > so, > > > >> > > > > > >> > > > is there a way to extend the code by including more advanced > > > >> > > > >> scheduling > > > >> > > > >> > > > functions ? > > > >> > > > > > > >> > > > Best regards, > > > >> > > > PhD Team > > > >> > > > > > > >> > > > 2014-10-21 16:11 GMT+01:00 Josh Thompson < > > > > [email protected]>: > > > >> > > > > -----BEGIN PGP SIGNED MESSAGE----- > > > >> > > > > Hash: SHA1 > > > >> > > > > > > > >> > > > > Khder, > > > >> > > > > > > > >> > > > > The scheduling of reservations is actually done in the web > > > > code. > > > > > >> Have > > > >> > > > >> > > a > > > >> > > > > > >> > > > > look > > > >> > > > > at the isAvailable function in the web/.ht-inc/utils.php > > > >> > > > > file. > > > > https://svn.apache.org/repos/asf/vcl/trunk/web/.ht-inc/utils.php > > > > > >> > > > > Josh > > > >> > > > > > > > >> > > > > On Tuesday, October 21, 2014 4:39:05 PM Khder Omar wrote: > > > >> > > > > > Dear all, > > > >> > > > > > > > > >> > > > > > We were wondering what kind of scheduler algorithms VCL > > > > might > > > > > >> use ? > > > >> > > > >> > > Any > > > >> > > > > > >> > > > > > hints about the scheduler source code will be appreciated. > > > > The > > > > > >> idea > > > >> > > > >> > > is > > > >> > > > > > >> > > > > > actually to check how VCL will perform while changing the > > > >> > > > >> scheduler > > > >> > > > >> > > > > > algorithm [in management node]. > > > >> > > > > > > > > >> > > > > > > > > >> > > > > > Thanks in advance > > > >> > > > > > > > > >> > > > > > Best regards, > > > >> > > > > > Phd team > > > >> > > > > > > > >> > > > > - -- > > > >> > > > > - ------------------------------- > > > >> > > > > Josh Thompson > > > >> > > > > VCL Developer > > > >> > > > > North Carolina State University > > > >> > > > > > > > >> > > > > my GPG/PGP key can be found at pgp.mit.edu > > > >> > > > > > > > >> > > > > All electronic mail messages in connection with State > > > >> > > > > business > > > >> > > > >> which > > > >> > > > >> > > > > are sent to or received by this account are subject to the NC > > > >> > > > >> Public > > > >> > > > >> > > > > Records Law and may be disclosed to third parties. > > > >> > > > > -----BEGIN PGP SIGNATURE----- > > > >> > > > > Version: GnuPG v2.0.22 (GNU/Linux) > > > > iEYEARECAAYFAlRGd60ACgkQV/LQcNdtPQPMjQCdF/28fx+VlhmZV0WEMobcv+7p > > > > > >> > > > > OAEAn1mct5Iz5bWrLnnX/yQl13wMVwRg > > > >> > > > > =RMTU > > > >> > > > > -----END PGP SIGNATURE----- > > > >> > > > > > >> > > - -- > > > >> > > - ------------------------------- > > > >> > > Josh Thompson > > > >> > > VCL Developer > > > >> > > North Carolina State University > > > >> > > > > > >> > > my GPG/PGP key can be found at pgp.mit.edu > > > >> > > > > > >> > > All electronic mail messages in connection with State business > > > > which > > > > > >> > > are sent to or received by this account are subject to the NC > > > > Public > > > > > >> > > Records Law and may be disclosed to third parties. > > > >> > > -----BEGIN PGP SIGNATURE----- > > > >> > > Version: GnuPG v2.0.22 (GNU/Linux) > > > >> > > > > > >> > > iEYEARECAAYFAlRSgzoACgkQV/LQcNdtPQMRBgCfaBOvBvUNnfdr5BLR7cnr+vMx > > > >> > > 5uQAniwpvKVjVGdW//rvNBYCKu485Siy > > > >> > > =xWum > > > >> > > -----END PGP SIGNATURE----- > > > >> > > > >> - -- > > > >> - ------------------------------- > > > >> Josh Thompson > > > >> VCL Developer > > > >> North Carolina State University > > > >> > > > >> my GPG/PGP key can be found at pgp.mit.edu > > > >> > > > >> All electronic mail messages in connection with State business which > > > >> are sent to or received by this account are subject to the NC Public > > > >> Records Law and may be disclosed to third parties. > > > >> -----BEGIN PGP SIGNATURE----- > > > >> Version: GnuPG v2.0.22 (GNU/Linux) > > > >> > > > >> iEYEARECAAYFAlRSieYACgkQV/LQcNdtPQOjlACfS97i9Hk0Tmspy+6vfgOcENht > > > >> UtYAn008A0w5VBq+eg5iGg1GRlff3zDB > > > >> =tCAJ > > > >> -----END PGP SIGNATURE----- > > > > - -- > > - ------------------------------- > > Josh Thompson > > VCL Developer > > North Carolina State University > > > > my GPG/PGP key can be found at pgp.mit.edu > > > > All electronic mail messages in connection with State business which > > are sent to or received by this account are subject to the NC Public > > Records Law and may be disclosed to third parties. > > -----BEGIN PGP SIGNATURE----- > > Version: GnuPG v2.0.22 (GNU/Linux) > > > > iEYEARECAAYFAlRal+cACgkQV/LQcNdtPQOAGACeL2Sanhs7ShZaCyKcSo5N2BYk > > wLEAn08YbcyiCmR4rY9u4kZJocfxY1Ju > > =pxdL > > -----END PGP SIGNATURE----- - -- - ------------------------------- Josh Thompson VCL Developer North Carolina State University my GPG/PGP key can be found at pgp.mit.edu All electronic mail messages in connection with State business which are sent to or received by this account are subject to the NC Public Records Law and may be disclosed to third parties. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iEYEARECAAYFAlRdPGkACgkQV/LQcNdtPQNFjACfdZm6YIKYhJ3EtamGXOfX1Dgs X90An3OeCGLL58j2VzzA96jTPfBuIDgI =w2De -----END PGP SIGNATURE-----
