Virtual machines

When time comes to develop or test applications then virtual machines may be used. Let me give  a definition of what a virtual machine is before I move further. Virtual machines are just like regular  computers, they usually exist in a virtual environment that contains a separate network to test the  application that is being developed. Virtual environment is an environment where machines are easily  spun up and destroyed without impacting other services on the network. Virtual machines like regular  computers have CPU, memory, disk space and networking. They utilize resources from a host  computer, where guest operating systems are installed. Virtual systems usually have lower hardware specs than their physical counterparts, because physical hardware is split onto multiple virtual computers.

Rollbacks are an important strategy, when new changes are to be deployed to production. Is it  possible to revert a change easily without rebuilding everything from scratch? Should be a question to  ask for all the changes that go into a production. It is necessary to pick a network with the smallest  number of computers, and wait before making a change in the main environment. This allows  engineers to find bugs in the production network on a smaller scale before moving to a big network. 

Virtual environment is easy to deploy and destroy without impacting your main environment, unless  your main environment consists of virtual machines. Virtual machines have a single drawback that is  hardly mentioned, it is performance. It is ok to deploy virtual machines in development or quality  assurance departments. Please review your production environment and measure the performance. If  it is low, that may be an indication that the production environment does not have enough traffic, and it is time to review what is being offered in the production environment and business decisions must be  made at that time. There are several periods in the business lifecycle of a company. Nobody expects  the company to be successful on the first day, it takes some time. However, if the business is not  bringing money after a while, maybe it is the wrong business. One of the reasons for that would be  that people are not ready for that, or maybe the business is ahead of its time and it will take longer to  make the business successful. Or the business is no longer valid, and the time is to close it. To close  the business is not a decision that is made lightly. So many people and perhaps their families depend  on the success of a business. 

However virtualization makes a lot of sense for the development and QA environments where the  changes need to be tested.

And utilization is light and predictable, it depends on users who test the changes. It  lowers the total cost of ownership for the company, and allows testing changes quicker. However, in a  production environment full system resources are needed and virtualization resources may be used after a careful analysis of systems utilization. If it is low then the question may be asked why it is so low in production. 

Please refer to the installation instructions for both of the products I have mentioned in this book as  the manuals may change over time.

Some companies decide to offer technology similar to virtualization. Such companies make hardware  available on demand, when it is needed. It may be needed in the data centers or to the developers to  test the latest changes. Expression “it works on my machine” is not a sufficient answer, the changes  are supposed to work in a production environment, and work reliably.

YouTube link video 1/2

YouTube link video 1/2

Advantages of virtual computers are the following:

1. Cost. They cost less then physical counterparts.

2. Abstraction of technology.

Study guide

Key Terms Glossary

Virtual Machine (VM)A software-based emulation of a physical computer system. VMs run on a host machine and utilize its resources to create a self-contained operating environment. Virtual Environment  A simulated computing environment that exists within a host machine or network. Virtual environments allow for isolated testing and development without affecting other systems. Host Machine The physical computer that provides resources and support for virtual machines. Guest Operating System The operating system running within a virtual machine. Rollback The process of reverting a system or application back to a previous state. This is often used to undo changes that have caused problems. Production Environment The live environment where a software application or system is actively used by end users. Development Environment A controlled environment where software developers build and test applications before they are deployed to production. Quality Assurance (QA)A process focused on ensuring software quality through testing and other methods. QA environments are used to identify and resolve defects before release. Utilization The extent to which a resource, such as CPU or memory, is being used. Total Cost of Ownership (TCO)The overall cost of acquiring, deploying, and maintaining a system or asset over its entire lifespan.

Short-Answer Quiz

What are the key components of a virtual machine?

Why are rollbacks an important strategy in software deployment?

Describe a potential drawback of using virtual machines in a production environment.

Why might a business decide to close down operations?

What are the benefits of using virtualization in development and QA environments?

Explain the significance of the phrase "it works on my machine" in the context of software development.

List two advantages of virtual computers over physical computers.

How does virtualization impact the total cost of ownership for a company?

Why is it crucial to consider system utilization when deciding whether to use virtualization in a production environment?

What is the recommendation regarding installation instructions for software products?

Short-Answer Quiz Answer Key

Key components of a virtual machine: Virtual machines, like physical computers, have CPU, memory, disk space, and networking capabilities. They draw resources from the host computer on which they are installed.

Importance of rollbacks: Rollbacks enable easy reversal of changes without rebuilding the entire system. They are crucial for mitigating the impact of errors or unintended consequences during software deployments.

Drawback of virtual machines in production: Virtual machines can have lower performance compared to physical servers because they share hardware resources. This can be a problem in production environments requiring high performance.

Reasons for business closure: Businesses might close due to lack of profitability, insufficient market demand for their products/services, being ahead or behind the market trends, or other operational challenges.

Benefits of virtualization in development/QA: Virtualization allows for easy deployment and destruction of test environments, isolates testing from the main system, and provides a cost-effective way to test changes quickly.

"It works on my machine" significance: This phrase highlights the inadequacy of testing solely on a developer's machine. Software needs to function correctly in the production environment, not just in isolated development setups.

Advantages of virtual computers: Two key advantages are lower cost compared to physical counterparts and abstraction of underlying hardware technology.

Virtualization's impact on TCO: Virtualization can lower the total cost of ownership by reducing hardware expenses, streamlining IT management, and enabling faster deployment of new systems.

System utilization and virtualization: Low system utilization in a production environment might indicate that virtualization isn't necessary and could even hinder performance. Careful analysis is needed before implementing virtualization in production.

Installation instructions: It is always recommended to refer to the most up-to-date installation instructions provided by the software vendor as manuals can change over time.

Essay Questions

Discuss the trade-offs between using virtual machines in a production environment versus a development environment. Consider factors such as performance, cost, security, and scalability.

Explain how virtualization can contribute to a company's disaster recovery and business continuity plans. How does it enhance flexibility and resilience in the face of system failures or data loss?

Analyze the implications of the statement "It works on my machine." Why is it insufficient to rely solely on developer testing, and what additional measures can be taken to ensure software quality in production?

How has the emergence of cloud computing and "hardware as a service" models impacted the adoption and use of virtualization technologies? Discuss the similarities and differences between these approaches.

Evaluate the ethical implications of virtualization, particularly in terms of resource consumption and environmental impact. Does the use of virtualization contribute to greater energy efficiency, or does it create new challenges for sustainable computing?

Virtual Machines: FAQs

1. What is a virtual machine (VM)?

A virtual machine is a software-based emulation of a physical computer. It operates within a virtual environment on a host computer and utilizes the host's resources, including CPU, memory, disk space, and networking. VMs function like regular computers, allowing users to install and run operating systems and applications.

2. How do virtual machines impact performance?

VMs typically have lower performance compared to physical machines because they share hardware resources with other VMs on the host computer. While suitable for development and testing environments, VMs in production may require careful analysis to ensure sufficient resources are allocated for optimal performance.

3. When are virtual machines appropriate for production environments?

Using VMs in production environments requires a thorough evaluation of system utilization. If resource utilization is low, it might indicate a lack of traffic and potentially signal underlying business issues. However, VMs can be advantageous in production if resource utilization is carefully analyzed and sufficient resources are allocated.

4. What are the advantages of using virtual machines?

Virtual machines offer several benefits, including:

Cost savings: VMs are generally less expensive than physical counterparts, reducing hardware and maintenance costs.

Technological abstraction: VMs allow users to work with various operating systems and software without being limited by the underlying physical hardware.

Ease of deployment and destruction: VMs can be quickly created and removed in virtual environments without affecting other systems.

Enhanced testing capabilities: VMs facilitate efficient testing of software changes in isolated environments, reducing the risk of impacting production systems.

5. What is the importance of rollbacks in production deployments?

Rollbacks are crucial for mitigating the impact of faulty deployments in production. They allow for the quick reversal of changes, restoring the system to a previous stable state without requiring a complete rebuild. Implementing rollbacks ensures minimal downtime and service disruptions.

6. How can companies avoid the "it works on my machine" issue?

To ensure software functions reliably in production, testing in environments that closely mirror the production setup is essential. While individual developer machines might exhibit successful results, discrepancies in configurations and dependencies can lead to issues in production. Utilizing virtual machines that mimic the production environment helps identify and resolve potential problems before deployment.

7. Can companies access virtualization technology without managing their own infrastructure?

Yes, some companies provide virtualization services where hardware resources are available on demand. This approach allows organizations to access virtualized environments for development, testing, or even production purposes without the need to invest in and maintain their own physical infrastructure.

8. What are the key considerations when deciding on the use of virtual machines?

Purpose: Determine the intended use of the VMs, whether for development, testing, or production.

Resource requirements: Assess the necessary CPU, memory, storage, and networking capabilities for the intended applications and workload.

Performance expectations: Understand the potential performance limitations of VMs compared to physical machines and ensure sufficient resources are allocated.

Cost analysis: Evaluate the costs associated with virtual infrastructure, including hardware, software, and management overhead.

Security implications: Consider the security measures required to protect VMs and data within the virtual environment.

Briefing 

Key Themes:

Virtual Machines in Development and Testing: VMs are a valuable tool for developers and QA teams. They offer an isolated environment to test changes without impacting the main production environment. The ease of deployment and destruction, coupled with lower hardware requirements, makes VMs cost-effective for these purposes.

"Virtual environment is easy to deploy and destroy without impacting your main environment..."

Performance Considerations in Production: While beneficial for development and testing, VMs can pose performance challenges in production environments. Due to shared resources and lower hardware specifications, VMs might not deliver the necessary performance for high-traffic production systems.

"Virtual machines have a single drawback that is hardly mentioned, it is performance. ... Please review your production environment and measure the performance. If it is low, that may be an indication that the production environment does not have enough traffic..."

Strategic Use of Virtualization: The decision to use virtualization in production should be based on a careful analysis of system utilization and business needs. If utilization is consistently low, it may signal underlying issues with the product or service offered.

"If it is low then the question may be asked why it is so low in production."

Alternatives to Virtualization: Some companies offer alternatives to traditional virtualization, providing on-demand access to hardware resources for development and testing. This approach helps ensure that code works reliably in production environments.

"Expression “it works on my machine” is not a sufficient answer, the changes are supposed to work in a production environment, and work reliably."

Important Ideas/Facts:

Definition of Virtual Machines: VMs are essentially software emulations of physical computers, with their own CPU, memory, disk space, and networking capabilities. They operate within a host computer and utilize its resources.

Rollbacks and Testing: The source emphasizes the importance of implementing rollback strategies when deploying changes to production. Testing in a smaller-scale network before deploying to the main environment is crucial for identifying and mitigating potential bugs.

Advantages of VMs: The key advantages of VMs are cost reduction, abstraction of technology, and simplified testing processes.

Business Lifecycle: The document touches upon the importance of evaluating business viability and making difficult decisions, including closing a business if it fails to generate revenue after a reasonable period.

Quotes:

"Virtual machines are just like regular computers, they usually exist in a virtual environment that contains a separate network to test the application that is being developed."

"Virtual machines have a single drawback that is hardly mentioned, it is performance."

"It is necessary to pick a network with the smallest number of computers, and wait before making a change in the main environment."

Recommendations:

Carefully consider the performance implications before implementing virtualization in production environments.

Conduct thorough testing in isolated environments, including smaller-scale networks, to ensure the reliability of code changes in production.

Regularly evaluate system utilization and business performance metrics to make informed decisions about resource allocation and product/service offerings.

This briefing document provides a concise overview of the key considerations regarding virtualization in software development and production. By understanding the benefits and limitations of VMs, organizations can make more informed decisions about their technology infrastructure.