Got contacted by a Citrix (XEN) representant today… they finally did their homework and do some follow-up on sales/potential customer.
This is well planned because VMWare is having some very big problems and their solution really suck. Summary, if you have this specific version [ESX 3.5 Update 2 ISO], you should really not shut-down your VM.
Executive summary : Give me 10k$, a month, 3 poweredge servers, a gigabytes capable switch and I’ll build you a scalable cloud infrastructure ;-).
And, the post:
Last year dominant meme was "Virtualization". Since you can’t have the same focus for two consecutives years (must be a law about that written somewhere), they (for various definition of "they") had to enhance it. Here come "Cloud Computing".
Cloud computing, as defined here, here, here, here, here and… is still in condensation phase. Ideas appear and usability should emerge… soon.
While this is concentrated fun for theorician, I would prefer a more technical discussion. I am aware of Montreal based corporations currently studying Cloud/Grid systems. One of the next big player, in Montreal/North-Eastern USA, might be iWeb Technologies - they already have hardware, a customer base and so much to gain on the scalability aspect of cloud computing. Think about dynamically closing unused shared hosting system and relocating instance in relation of their impact on server resources. A lot of other corporation are also present in the field.
But I don’t have access to the same quantity of hardware as they have, so lets see what is available / can be built in my small lab.
SunGrid Engine, as an online service, no hardware needed, have more of a grid heritage than a cloud computing future. Application are launch, run, and a specific output is gathered and sent. The list of application, while impressive, doesn’t have "Apache" - this is a system meant for raw processing power, not offering services.
IBM’s BlueCloud is still more of a vapor cloud around a press release than anything that has to do with computing. Though, I’m sure it look awesome in their lab. But, again, I’m sure their whole lab look nice.
3TERA’s apps logic does look neat, yet, there is no public price tag. This also look like the kind of system that is built around templates "which should not be modified". I have no idea how the system reliability goes when customization are made. And I won’t know… no price tag is a straight no-go for me. If you are ashamed of your pricing model, there is a problem. If its not the case, there is no reason not to show "figures".
Another online service, Amazon AWS (EC2 & S3), is one of the current market leader. Based on XEN, you can have a remote instance for couples of cents an hour. The main concern with EC2 is the volatile aspect of the storage, which kinda defeat most of services real purpose, dealing with informations.
So ?
While I don’t have much hardware, I still have a labs of 4 dev + 2 prod systems. Lets see what can be done. Lets design a home brewed cloud infrastructure.
Nodes types
ConfigNode :
role : CNode is a standard Debian sys. It is the DHCP + PXE + tftp server. It hold the HardwareNode kernel. All cloud configuration happen on those systems.
min : 1 sys.
normal : 2 sys.. {Primary/Slave}. with software raid + drbd + heartbeat.
Scalable: no use. 2 systems is more than enough, there isn’t really any CPU/Network load.
StorageNode :
role: SNode is a network booted GNU/Linux system. It serve AoE devices on the network. All nodee (except ConfigNode) use SNODE as root filesystem.
min: 1 sys.
prefered: 2 sys, {Primary/Primary} with software raid + drbd. MD-device Multipathing is required from clients to preserve the P/P coherence and reliability to network failure.
Scalable : This is a building block. The limit of SNODE is defined by the network fabric speed.
HardwareNode :
role : HNode is a network booted GNU/Linux/XEN-dom0 system. It use a SNODE array as its root filesystem. This is where INODE will be launched. This node is diskless.
min: 1 sys.
prefered: no limit.
Scalable: This is a building block of the infrastructure. The limit of HNODE is defined by the acceptable speed of the root file system located on a SNODE.
Instance :
role : an Instance is a network booted GNU/Linux/XEN-domU system. In the presence of VT technologies, it can also be an unmodified guest operating system (hear full-fledge GNU/Linux or Microsoft Windows). It is started on a specific HNODE using SNODE resources.
min : 1 sys.
prefered : no limit.
Scalable : Currently limited to the underlying HNODE ressources.
Summary : Using a specific configuration node we start a StorageNode and an hardware node. Then, once the infrastructure is "running", Instances can be dynamically started on HardwareNode.
Since Instances are XEN/domU based, running on shared storage, they can be migrated LIVE without downtime between HardwareNode. A ping to the virtual instance would not fail, even in the middle of the live migration.
Since HardwareNode are network booted, adding new server is as simple as adding the MAC addrs in the dhcp configuration and tagging it as HNODE. As long as system are able to PXE boot, it is really a matter of minutes to add new nodes.
Since HardwareNode are network booted with remote root filesystem, they do not need to have hard drive. This remove one of the main failing pieces of current infrastructure. There isn’t much to fail in a server with only a CPU, memory and network interfaces.
The storage aspect is taken care of Storage node where good raid + redundancy + hard-drive snapshot can be used to control the environment. The only limit on the number of storage node is the network… but then, link aggregation is your friend.
Since multipathing is used, with DRBD and AoE, a storage node can be shutdown without impacting running instances.
The creating of new InstanceNode is easy : either copy an instance or debootstrap a new system. Doing something similar from 3Tera would be fairly easy at this point, creating template and preparing configuration interfaces/scripts.
What now ?
Took me a week-end day. I have a running ConfigNode, StorageNode (using NFS, but AoE /multipathing is next), HardwareNode and an Instance. Much of the time was spent waiting for kernel compilation and deploying distcc on my lan. Had little problems pxe booting a dom0, but found a fix.
I wonder what someone working full time could accomplish in a month…. Someone want to pay me to see ? ;-). Haaa.. and it would cost you (in addition to my salary for a month) a copy of Nicolas Carr’s BigSwitch book (which I haven’t read yet, but plan to, as soon as I can get my hand on a copy). I can even do a little presentation first for some kind of financial retribution (yeah, money drive me ;-)).
Seriously, such setup would be fully scalable and so easy to dynamically configure through scripts/GUI. One of the limiting factor is the CPU/Memory resources limit that instance have since they are linked to a single hardware node but if Xen (as a commercial solution) is able to create a resource pool, I’m sure there is way to go around that limitation.
Jeez, using VT enabled hardware node, you could even start Microsoft Windows instance in your cloud…
Btw, I know that everything i’ve spoke about can be done through VMWare infrastructure with vmotion (and maybe 3Tera’s Apps) but…. then, think about the fact that a 2 CPU licence for VMWARE Infrastructure is a little bits over 6900$USD….
I just don’t understand why there isn’t more cloud out there. This isn’t all that hard to deploy… not even time consuming…
.
