Virtualization Technologies

Correct Answer: Virtual Local Area Network (VLAN)

The best answer is 'Virtual Local Area Network (VLAN)'. VLANs are used to isolate traffic between devices on the same network or subnet. It helps in segregating traffic between virtual machines, even on the same subnet which is exactly what the scenario is asking for. 'Network Address Translation (NAT)' translates the IP addresses of network's nodes into different IP addresses for routing purposes, but it doesn’t segregate network traffic. 'Bridge Mode' simply connects two networks and allows them to communicate with each other, without the segregation required in this scenario. Lastly, 'Port Forwarding' redirects a communication request from one IP address and port number to another, again this doesn't segregate network traffic, instead it is used to make a machine on the local network accessible from the internet.

Correct Answer: Configure resource allocation settings

The best response to ensure fair distribution of network resources among virtual machines is to 'Configure resource allocation settings'. These settings allow the administrator to control how much resources each VM can use, preventing one from taking more than its fair share. Creating another VM for load balancing would not necessarily ensure fair distribution of resources, they might create a bottleneck or increase the resource contention. Decreasing CPU and memory on all VMs is counter-productive and won't necessarily distribute resources fairly. It might simply cause all VMs to perform less efficiently. Disabling some virtual machines to free up resources is not a good solution since it would limit functionality and could also create issues with applications or services running on those VMs.

Correct Answer: Implement application containerization

To optimize the performance of a virtualized web server running multiple web applications, the best method would be to implement application containerization. Containerization enables independence between software applications by encapsulating them in a 'container' with their own operating environment. This not only provides effective isolation of each application, but it also improves efficiency as each container utilizes only the resources it needs, thus minimizing resource usage. The other options are less effective: Decreasing CPU and memory allocation could likely degrade performance rather than improve it. Though configuring the web server to use software-based RAID might improve data redundancy and potentially read speed, it would not help with isolating each application and improving efficiency. Using a network bridge for each application would not isolate the applications on the same server and would consume additional network resources.