Virtualization and CPU Organization Basics

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Questions and Answers

What is the primary benefit of the Disco project?

Developing operating systems from scratch

Facilitating peer-to-peer networking functionalities

Enhancing gaming performance on single-threaded applications

Enabling efficient operation on shared memory multiprocessors (correct)

What was the initial product focus of VMWare?

Developing custom hardware solutions

Offering cloud storage solutions

Providing virtual machines for development and testing (correct)

Creating a new operating system

Which of the following is a disadvantage of virtualizing with dynamic binary translation?

Does not support legacy applications

Slower compared to direct execution (correct)

Incompatible with modern processors

Requires significant changes to the operating system

What is the main strategy behind server consolidation in VMWare's offerings?

Consolidating multiple lightly used services to reduce costs Signup and view all the answers

What technique does QEMU use for virtualization?

Dynamic binary translation Signup and view all the answers

What is the primary function of namespaces in a virtual machine environment?

They restrict processes to see only certain resources and enforce isolation. Signup and view all the answers

Which component is essential for creating containerized processes alongside namespaces?

Cgroups Signup and view all the answers

What significant limitation did early LXC face compared to the demands of developers?

It lacked the ability to efficiently manage shared images among containers. Signup and view all the answers

Which of the following is NOT a characteristic of Linux containers?

They require a hypervisor to operate. Signup and view all the answers

Why do developers need consistency in configurations across different servers?

To guarantee that dependencies are met and applications run as intended. Signup and view all the answers

What does a Type 2 Hypervisor rely on to operate effectively?

A host operating system Signup and view all the answers

Which of the following is NOT one of the methods to implement virtualization?

Nested Virtualization Signup and view all the answers

Which part of the Instruction Set Architecture (ISA) is primarily focused on system resource management?

System ISA Signup and view all the answers

What are traps and interrupts associated with in CPU organization?

Error detection and handling Signup and view all the answers

In hardware-assisted virtualization, what is primarily used to facilitate the isolation of guest operating systems?

Hypervisor privilege levels Signup and view all the answers

What role does the MMU play in the architecture of a CPU?

It handles memory address translations. Signup and view all the answers

Which component is critical for fetching, decoding, and executing instructions in software virtualization?

Fetch/Decode/Execute pipeline Signup and view all the answers

What is the main function of page tables in system virtualization?

To translate virtual addresses to physical addresses Signup and view all the answers

What percentage of time is typically spent on package installation?

80% Signup and view all the answers

For a lightweight HTTP application, what is the issue with container startup time?

Containers take too long to start. Signup and view all the answers

Which of the following is NOT a benefit of serverless functions?

Guaranteed server uptime. Signup and view all the answers

What aspect of serverless functions helps minimize network copying?

Encouraging specific runtimes. Signup and view all the answers

What was the median response time for AWS Lambda RPC in the experimental setup?

1.6s Signup and view all the answers

In the context of serverless functions, what does 'no spinup time' imply?

Functions are instantly accessible. Signup and view all the answers

What is a limitation of containers in the context of flash crowds?

They are slow to respond to bursts in demand. Signup and view all the answers

Which of the following best describes the AWS Lambda billing model?

Pay-as-you-go based on function execution. Signup and view all the answers

What was a primary motivation behind the development of Docker?

To solve issues related to application packaging and deployment Signup and view all the answers

Which component manages container images in Docker?

Containerd Signup and view all the answers

What is a fundamental difference between containers and virtual machines?

Containers share the host OS kernel while VMs do not Signup and view all the answers

Which of the following is NOT a function provided by Docker?

Creating a new operating system image Signup and view all the answers

What does the term 'elasticity' refer to in the context of Docker containers?

The ease of scaling up or down containers as needed Signup and view all the answers

Which of these container runtimes is a low-level container runtime?

runC Signup and view all the answers

What is a key benefit of using containers in software development?

They allow for faster build, test, and deploy cycles Signup and view all the answers

What is meant by the term 'high-level container runtimes'?

Services that handle image format, management, and sharing Signup and view all the answers

How does Google utilize container technology according to the case study?

Using an internal container platform known as Google Borg Signup and view all the answers

Why do containers generally require less disk space compared to virtual machines?

Containers share the host OS kernel and libraries Signup and view all the answers

Study Notes

### Guard Application

A new instance of Windows runs at the hardware layer, with an independent copy of the kernel and Windows Platform Services
Microsoft Edge is run by the instance
The hardware restricts access to the user's normal operating environment

Type 2 Hypervisor

Virtual Machine Monitors (VMMs) are built on top of a host operating system
The host operating system handles resource allocation and provides execution environments for guest operating systems
User-mode Linux (UML) and QEMU are examples of Type 2 Hypervisors

Virtualization Methods

Popek-Goldberg VMMs
Dynamic Binary Translation
Hardware-assisted Virtualization

CPU Organization Basics

Instruction Set Architecture (ISA) describes the state visible to the programmer: registers and memory, and instructions that operate on the state
ISA is typically divided into two parts: User ISA and System ISA

### User ISA

The part of ISA that is mostly used for computation
The State includes registers and memory

### System ISA

The part of ISA that is mostly used for system resource management
Privilege levels, control registers, traps and interrupts, MMU (including page tables and Translation Lookaside Buffer (TLB), and I/O device access are part of the System ISA

### Virtualization with Interpretation

Fetch/Decode/Execute pipeline is executed in software
Instructions are converted to the minimal set of host instructions
Designed for use by debuggers to set breakpoints

Disco

Disco operating system allows multiple copies of the Silicon Graphics IRIX operating system to run on Stanford Flash Multiprocessors
Disco was built to run on shared memory multiprocessors
The Stanford Flash is a cache coherent NUMA (Non-Uniform Memory Access) system
Disco evolved into VMWare, built by the same creators

VMWare

The initial product was to help developers with testing
The "killer" product was server consolidation in enterprise environments
Server consolidation resulted in cost reduction and better management
VMWare now generates over 90% of its revenue from server consolidation

Virtualization with Dynamic Binary Translation

Guest instructions are translated into host instructions
Translation caching reduces overhead
Still slower than direct execution
QEMU performs this type of translation

### Namespaces

Namespaces allow for process isolation
Examples include network isolation, process IDs, mounting, and inter-process communication

From Virtual Machines to Linux Containers

Cgroups and namespaces can be used to create containerized processes
LXC (Linux Containers) is user-land software providing isolated Linux environments on a single host
LXC can be used to run multiple Linux distributions as containers

From LXC to Docker

Docker was built to address developer needs
Docker supports container image formats and building, managing, sharing, and running container images using Dockerfile, docker build, docker images, docker rm, docker ps, docker push/pull, and docker run
Docker provided solutions for moving images, copy-on-write, sharing previously created images
Docker addresses dependencies and configurations when building, testing, and deploying applications across servers by packaging application and dependencies as container images

### Container Ecosystem Today

Low-level container runtimes manage namespaces, control groups, and container execution (e.g., runC, lxc, rkt)
High-level container runtimes handle image formats, image management, and image sharing (e.g., cri-o, containerd)
Docker is a collection of components, including the Docker engine (a user-facing daemon, REST API, and CLI) and a runtime (containerd, container-shim, and runC)

### Advantages of containers

Abstraction levels: Hypervisors work with hardware abstraction while containers work at the OS abstraction level
Density: Containers require less space than virtual machines
Elasticity: Easier to scale containers than virtual machines
Improved software development lifecycle: Building, testing, and deploying are made easier with containers

### Serverless Functions

Serverless function handlers run in response to events including web requests, database updates, and scheduled events.
Function invocations are based on a pay-per-use model where billing depends on the time and memory used during each function invocation.
Server pool sharing with customers allows for efficient utilization of resources.
Serverless functions encourage specific runtimes for minimal network copying and code residency in memory.

Architecture

Architecture is characterized by a function request, function registry, and scaling engine. The function registry contains the function code, while the scaling engine controls the deployment and scaling of functions.

Functions vs Containers

Experimental setup used Elastic Beanstalk (autoscaling cloud service) and AWS Lambda (serverless functions for AWS)
Workload simulation uses 100 concurrent HTTP requests and 200 ms compute time per request for one minute
AWS Lambda RPC has a median response time of 1.6 seconds due to efficient startup of 100 worker instances, compared to 20 seconds for Elastic Beanstalk.

### Scalability Result

AWS Lambda RPC has a median response time of only 1.6s.
Lambda was able to start 100 unique worker instances within 1.6s.
An RPC in Elastic Beanstalk often takes 20s.

Three Generations of Virtualization

There are three generations of virtual machines, the latest includes serverless computing.

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Description

This quiz covers key concepts in virtualization, including Guard Applications, Type 2 Hypervisors, and various virtualization methods. Additionally, it explores the fundamentals of CPU organization and the Instruction Set Architecture (ISA), distinguishing between User ISA and System ISA. Test your understanding of these critical components in computer systems.