ClouD-ynamics – From Technical to Layman

The new budding technology, otherwise known as cloud computing is attached to multiple advantages including efficiency, accessibility and ease of use. This entry explains some of these advantages as one of our engineers gives concrete illustrations of some of the processes that make up the dynamics of cloud computing. Cloud Computing in a Nutshell The great idea behind cloud computing is the separation of the software and hardware.  Before cloud, in order to put up a website, one would buy a server, have it setup and OS installed by a technician, and send it off to the data-center to be tucked into a rack with power, network, and cooling.  Now software designers can concentrate on the OS and their software while the provider takes care of the physical hardware. How? They make sure that the physical hardware underlying the virtual machines keeps running.  If that is working well, accessibility and cloud  flexibility services to the virtual machines running on them can be provided -  services not available to those running their own hardware and software. User monitoring of the cloud The virtual machines the customer uses acts just like a physical machine.  This is so the customer can install the server OS they need and everything performs as it should.  So the customer manages everything inside that virtual machine.  But wrong configurations, user mistakes, malicious code, bad updates, traffic spikes, run-away processes, etc do still happen inside the virtual machine.  Therefore the user knows best what to monitor and how to fix it. Monitoring alerts and such give the user more control and warning without having to constantly watch the server themselves.  For most situations the user can decide what should be done and they are given the tools available to a cloud service. Addressing issues arising from the provider's services When the situation arises where the problem is in the provider's physical hardware or cloud services and not the user's virtual machine, there are methods for solving those:

• Physical hypervisor failure:  This is automatically detected on the provider side and the virtual machines are moved to another hypervisor.
• Damage to the virtual machine directory:  Some major change to the virtual machine disk directory, kernel, or such.  This is where automated backups help.
• Performance de-gradation: Hot/Cold migration allows the user to test out on another hypervisor.
• Minimizing effects of hypervisor crash: Separating the virtual machines by migrating to separate hypervisors makes this possible.

What can a user gain from monitoring performance? Monitoring setup by the user should catch common problems the user can fix.  Some may include overloaded virtual machines and/or services, services that stop responding. If the problem lies elsewhere the user can check any maintanence/trouble reports posted on the control panel by the provider.  If those don't seem to be solving the problem then the user should contact the provider where they can example the virtual machine and see where the problem is. What is the difference between a hot migration and a cold migration? The migration function is yet another advantage of using virtual machines in Cloud computing systems. There are two types of migration function: hot and cold. Hot migration is the transfer of the OS and applications from virtual machines to physical machines without stopping OS operations or applications. In a highly demanding environment such as a public cloud, with even the best servers, the risk of failure starts to rise after around 3 years. The hot migration function easily avoids downtime caused by failure and maintenance issues with physical machines. Hot migration fulfills several needs:

• Frees up a given physical server for maintenance without downtime for users;
• Dynamically balances workloads among physical servers so that they all run at optimal levels;
• Prevents a facility’s under-performing servers (or those on the brink of failure) from interrupting operations.

Hot migration can be seen as a service not offered by the traditional non-cloud setup.  Also, it means flexibility and choice when the user understands they can protect themselves from the physical hardware underneath. Cold migration, meanwhile, suspends OS and applications on virtual machines before transferring them to physical machines. Types of migration available depend on the hypervisor selected. With cold migration, you have the option of moving the associated disks from one datastore to another. The virtual machines are not required to be on shared storage. The virtual machine you want to migrate must be powered off prior to beginning the cold migration process.

Be Part of Our Cloud Conversation

Our articles are written to provide you with tools and information to meet your IT and cloud solution needs. Join us on Facebook and Twitter.   About the Guest Author: Bryan Kinney is a technical engineer at GMO Cloud. He has been working in the I.T. field for the last 18 years but have been into computers personally for 29 years.  Always loves good logical puzzles and non-logical human ones too.  Originally from the Northwest USA and can get into hiking and survival camping.