To maintain a visualized solution we must focus on three aspects speed, stability, and security. Visualization offers many benefits such as isolation, live migration and intrusion detection. We can easily perform maintenance on a virtual machine by creating a snapshot of it when it is first installed allowing us if mistakes are made or the virtual machine is corrupted we can recover in just a matter of minutes to the snapshot. Using live migration to seamlessly move one virtual machine to an other physical server to balance the load on the server can improve performance and reliability of the visualized solution.
There are two options when using live migration seamless live migration and Pre-copy memory migration. Pre-copy memory migration is spit into three phases : Warm up phase , stop and copy phase and post copy memory migration . Warm up phase refers to the phase where the hyper visor copies all the memory pages from the source destination while the virtual machine is still running on the source . Stop and copy phase refers to the phase where the Virtual machine will be paused copying and page files left to the destination host and the virtual machine resumes on the destination host . The larger the memory of the applications running on the VM the larger the downtime of the virtual machine but downtime is almost zero since this process takes just a few milliseconds and the end user wont even notice.
Our visualization environments need to be secure that is why each virtuliased os is isolated allowing each one to work independently without conflicting with other systems. One issue which many network administrator are aware of is the attacks from inside the network. VM patching and user permissions are a must for any network and VM. We must split virtual machines into segments and form teams of people that can access these virtual machines. For example the accounting team can only access Virtual machines that are used for accounting software but cannot access the Virtual machines that are using in fields like engineering . Vendors such as Vmware offer products for extensive privilege management and compliance . This can allow us to limit what user can and cannot do which can help strengthen the security of the virtualized environment.