virtualization module

virtualization/virtual_machines.md

@@ -0,0 +1,37 @@
+**Question 1**
+
+Run the Linux OS as a virtual machine, or run the application in a containerized Linux environment (which
+is the same abstraction).
+
+**Question 2**
+
+A native system virtual machine has dedicated hardware to run the hypervisor, while a hosted system 
+virtual machine runs a hypervisor as a process in the operating system.
+
+**Question 3**
+
+A virtual machine hosts an entire operating system and requires users to perform configuration if they
+want to run an application, whereas a Virtual Appliance is built to provide an easy plug-and-play virtual 
+machine image built to run some specific software stack.
+
+**Question 4**
+
+In a large application sense, containerizing services into their own virtual machines allows for easier
+replication, scaling, and networking. Instead of running several smaller servers, one large server can
+host several applications in parallel. This provides a good seperation of concern. And, if one service 
+goes down, the whole system does not go down with it.
+
+Locally, it can help in development when targeting another operating system. Virtual machines can be
+used to verify builds without installing a whole other operating system.
+
+**Question 5**
+
+A virtual machine monitor is just another term for a hypervisor, so, see question 2.
+
+**Question 6**
+
+The three components of a virtual machine are:
+
+1. The host
+2. The virtualization layer
+3. The guest

virtualization/virtualization.md

@@ -0,0 +1,101 @@
+**Question 1** 
+
+I use an Apple Silicon Mac which is based on the ARM architecture - so it's necessary to use 
+[Multipass](https://multipass.run/), as native virtualization is _not available to us_.
+
+![No Virtualization Strings](./img/no_virtualization.png)
+
+**Question 2**
+
+One of the downsides of running a virtual machine, as opposed to a hosted virtual instance, is that local
+resources are used. On a laptop especially, this increases power draw, draining the battery. Additionally,
+the security of mind provided by "faster disaster recovery", as discussed in the article, is not as 
+necessary for consumer applications on personal machines as servers. Finally, virtual machines are 
+inherently slower in compute due to general overhead.
+
+**Question 3** 
+
+![htop resources](./img/htop.png)
+
+**Question 4** 
+
+In a large application sense, containerizing services into their own virtual machines allows for easier
+replication, scaling, and networking. Instead of running several smaller servers, one large server can
+host several applications in parallel.
+
+Locally, it can help in development when targeting another operating system. Virtual machines can be
+used to verify builds without installing a whole other operating system.
+
+**Question 5**
+
+A native system virtual machine has dedicated hardware to run the hypervisor, while a hosted system 
+virtual machine runs a hypervisor as a process in the operating system.
+
+**Question 6**
+
+1. Easier networking between "servers"
+2. Efficient resource use
+
+**Question 7**
+
+A Virtual Appliance is built to provide an easy plug-and-play virtual machine image built to run some 
+specific software stack.
+
+**Question 8** 
+
+A Virtual Appliance would be desirable to eliminate maintenance and configuration overhead when running an
+application. In my own experience, I've used a form of virtual appliances - "Docker Containers", to easily
+spin up multiple versions of small services at work.
+
+**Question 9** What are 2 benefits of Virtualization?
+
+See question 6.
+
+**Question 10** 
+
+See question 4.
+
+**Question 11** 
+
+See question 8.
+
+**Question 12**  What are the three main types of virtualization?
+
+1. Full virtualization
+2. Para virtualization
+3. OS-level virtualization
+
+**Question 13** What you should know about virtualization?
+
+How to create a virtual machine, and maintain it.
+
+**Question 14** What is the weakness of virtualization?
+
+Inherent overhead in all system operations.
+
+**Question 15** What are the six areas of virtualization?
+
+Source: [HiTechNectar](https://www.hitechnectar.com/blogs/virtualization-types)
+
+1. Application - run individual applications in a seperate environment than a host OS
+2. Data - abstract exact location and formatting information away from retrieval of data
+3. Desktop - hosts a desktop environment virtually on another machine (reminds me of mainframes).
+4. Network - physical networking tools are abstracted into software resources
+5. Server - division of a server into multiple guest operating systems
+6. Storage - abstraction over multiple storage arrays into a single pool
+
+**Question 16** What is the biggest challenge in virtualization?
+
+Resource distribution is a big one; it's difficult to keep track of several resources on a host machine 
+and ensure a Virtual Machine accesses them correctly.
+
+**Question 17** What is the risk of using virtualization?
+
+The biggest risk of using virtualization is sandbox escape vulnerabilities. Although mostly research and
+proof-of-concept, highly skilled engineers can theoretically craft exploits to escape the sandbox of the
+VM and directly mess with the host operating system.
+
+**Question 18**
+
+When (question 17) is trusted; sandboxing. Virtualization should supply no access to resources within the
+host operating system.