IBM SmartCloud Provisioning is a breakthrough entry-level solution that allows quick cloud deployment and
features automated provisioning, parallel scalability and integrated
fault tolerance to increase operational efficiency and respond to user
needs. It also provides the foundation to integrate more advanced cloud
capabilities.
I’ve been impressed by
the speed of provisioning a set of virtual machines in just a few tens
of seconds using IBM SmartCloud Provisioning. In most cases, you can get
a running virtual machine in less than one minute.
The IBM SmartCloud Provisioning technology has been devised and
particularly optimized for managing the following cloud infrastructure
scenarios:
- Infrastructure composed of homogenous resources
- High level of standardization with a relative small set of master images used to provision many instances from the same image
- Typical life cycle of the provisioned resources with short average time of life of provisioned virtual instances
Many other workloads can be deployed and easily automated on top of
IBM SmartCloud Provisioning. For example, traditional stateful
applications can be easily deployed for simple high availability (HA)
solutions. Anyway, you get the maximum performances from SmartCloud
Provisioning when operating in the context of the above scenarios.
To achieve such high performances, IBM SmartCloud Provisioning has
been designed to focus the attention to an optimized virtualization
infrastructure based on OS streaming: no need to copy large image files
over the network when provisioning.
Image copying is the single biggest bottleneck in virtual machine
(VM) provisioning today, in terms of CPU, memory, I/O, and bandwidth
usage. In traditional cloud provisioning approaches, all of this
overhead is system resource that is just pure overhead (nobody builds a
cloud to provision systems ―
provisioning is an overhead that is required to have systems on which
business workload is deployed, and any overhead is in conflict with the
business workload).
The key element of such infrastructure is the so-called ephemeral
instances, which are virtual machines having no persistent state. After
they are terminated, all the data associated with them is deleted also.
They are clones of a master image and these clones will have a primary
virtual disk that is ephemeral: when the instance goes, so does its
ephemeral storage (mechanisms exist in IBM SmartCloud Provisioning to
provide persistence, if needed by some scenarios).
When creating a new instance, because master images are read-only
resources and are replicated across the storage cluster, IBM SmartCloud
Provisioning uses the copy-on-write (CoW) technology and the iSCSI
protocol to stream them, avoiding expensive copying. Each iSCSI session
results in a valid block device to be created in the host OS.
Of course each guest OS (corresponding to a given instance) requires a
writable block device representing the main disk of the system. All
supported hypervisors have a storage virtualization layer that includes
the copy-on-write technology. For example, Kernal-based Virtual
Machine’s (KVM) qcow2 files can be configured to implement CoW by referencing a backing storage device. VMware has something called redo files,
which effectively do the same thing as well. In each case, the
hypervisor can natively use the CoW file referencing the iSCSI block
device to expose a virtual block device to the virtual machine.
Depending on the hypervisor and guest OS, this device will show up as something like one of the following lines:
/dev/sda
c:\
The CoW files are stored locally on the hypervisor’s file system.
When the instance is terminated, the IBM SmartCloud Provisioning
agent simply discards the CoW file and checks if any other instances are
using the same iSCSI device. If the device is no longer in use, the
agent also stops the iSCSI device.
Thanks to this infrastructure, the action of provisioning a new
virtual machine results in a very fast and reliable process that allows
it to create individual systems in tens of seconds, and of peak requests
of thousands of systems per hour.
Links:
- IBM SmartCloud Provisioning (official site)
- Download trial version
Update:
- 2012.05.09 - original post
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