#AWScloud

[qcsdclabs]

Understanding the Boot Process in Linux

                    Six Stages of Linux Boot Process

Press the power button on your system, and after few moments you see the Linux login prompt.

Have you ever wondered what happens behind the scenes from the time you press the power button until the Linux login prompt appears?

The following are the 6 high level stages of a typical Linux boot process.

                             BIOS        Basic Input/Output System

                             MBR        Master Boot Record executes GRUB

                             GRUB      Grand Unified Boot Loader Executes Kernel

                             Kernel      Kernel executes /sbin/init

                             Init            init executes runlevel programs

                             Runlevel   Runlevel programs are executed from /etc/rc.d/rc*.d/

1. BIOS

BIOS stands for Basic Input/Output System

Performs some system integrity checks

Searches, loads, and executes the boot loader program.

It looks for boot loader in floppy, cd-rom, or hard drive. You can press a key (typically F12 of F2, but it depends on your system) during the BIOS startup to change the boot sequence.

Once the boot loader program is detected and loaded into the memory, BIOS gives the control to it.

So, in simple terms BIOS loads and executes the MBR boot loader.

2. MBR

MBR stands for Master Boot Record.

It is located in the 1st sector of the bootable disk. Typically /dev/hda, or /dev/sda

MBR is less than 512 bytes in size. This has three components 1) primary boot loader info in 1st 446 bytes 2) partition table info in next 64 bytes 3) mbr validation check in last 2 bytes.

It contains information about GRUB (or LILO in old systems).

So, in simple terms MBR loads and executes the GRUB boot loader.

3. GRUB

GRUB stands for Grand Unified Bootloader.

If you have multiple kernel images installed on your system, you can choose which one to be executed.

GRUB displays a splash screen, waits for few seconds, if you don’t enter anything, it loads the default kernel image as specified in the grub configuration file.

GRUB has the knowledge of the filesystem (the older Linux loader LILO didn’t understand filesystem).

Grub configuration file is /boot/grub/grub.conf (/etc/grub.conf is a link to this). The following is sample grub.conf of CentOS.

#boot=/dev/sda

default=0

timeout=5

splashimage=(hd0,0)/boot/grub/splash.xpm.gz

hiddenmenu

title CentOS (2.6.18-194.el5PAE)

          root (hd0,0)

          kernel /boot/vmlinuz-2.6.18-194.el5PAE ro root=LABEL=/

          initrd /boot/initrd-2.6.18-194.el5PAE.img

As you notice from the above info, it contains kernel and initrd image.

So, in simple terms GRUB just loads and executes Kernel and initrd images.

4. Kernel

Mounts the root file system as specified in the “root=” in grub.conf

Kernel executes the /sbin/init program

Since init was the 1st program to be executed by Linux Kernel, it has the process id (PID) of 1. Do a ‘ps -ef | grep init’ and check the pid.

initrd stands for Initial RAM Disk.

initrd is used by kernel as temporary root file system until kernel is booted and the real root file system is mounted. It also contains necessary drivers compiled inside, which helps it to access the hard drive partitions, and other hardware.

5. Init

Looks at the /etc/inittab file to decide the Linux run level.

Following are the available run levels

0 – halt

1 – Single user mode

2 – Multiuser, without NFS

3 – Full multiuser mode

4 – unused

5 – X11

6 – reboot

Init identifies the default initlevel from /etc/inittab and uses that to load all appropriate program.

Execute ‘grep initdefault /etc/inittab’ on your system to identify the default run level

If you want to get into trouble, you can set the default run level to 0 or 6. Since you know what 0 and 6 means, probably you might not do that.

Typically you would set the default run level to either 3 or 5.

6. Runlevel programs

When the Linux system is booting up, you might see various services getting started. For example, it might say “starting sendmail …. OK”. Those are the runlevel programs, executed from the run level directory as defined by your run level.

Depending on your default init level setting, the system will execute the programs from one of the following directories.

Run level 0 – /etc/rc.d/rc0.d/

Run level 1 – /etc/rc.d/rc1.d/

Run level 2 – /etc/rc.d/rc2.d/

Run level 3 – /etc/rc.d/rc3.d/

Run level 4 – /etc/rc.d/rc4.d/

Run level 5 – /etc/rc.d/rc5.d/

Run level 6 – /etc/rc.d/rc6.d/

Please note that there are also symbolic links available for these directory under /etc directly. So, /etc/rc0.d is linked to /etc/rc.d/rc0.d.

Under the /etc/rc.d/rc*.d/ directories, you would see programs that start with S and K.

Programs starts with S are used during startup. S for startup.

Programs starts with K are used during shutdown. K for kill.

There are numbers right next to S and K in the program names. Those are the sequence number in which the programs should be started or killed.

For example, S12syslog is to start the syslog deamon, which has the sequence number of 12. S80sendmail is to start the sendmail daemon, which has the sequence number of 80. So, syslog program will be started before sendmail.

There you have it. That is what happens during the Linux boot process.

for more details visit www.qcsdclabs.com

[hackeocafe]

Top 5 Cloud Computing Skills for 2025 (Salaries Included)

In this video, he share the top 5 Cloud Computing Skills for 2025, and he included all the salaries for these skills as well as the Cloud Computing Jobs you can apply for.

[signiance]

Journey to Devops

The concept of “DevOps” has been gaining traction in the IT sector for a couple of years. It involves promoting teamwork and interaction, between software developers and IT operations groups to enhance the speed and reliability of software delivery. This strategy has become widely accepted as companies strive to provide software to meet customer needs and maintain an edge, in the industry. In this article we will explore the elements of becoming a DevOps Engineer.

Step 1: Get familiar with the basics of Software Development and IT Operations:

In order to pursue a career as a DevOps Engineer it is crucial to possess a grasp of software development and IT operations. Familiarity with programming languages like Python, Java, Ruby or PHP is essential. Additionally, having knowledge about operating systems, databases and networking is vital.

Step 2: Learn the principles of DevOps:

It is crucial to comprehend and apply the principles of DevOps. Automation, continuous integration, continuous deployment and continuous monitoring are aspects that need to be understood and implemented. It is vital to learn how these principles function and how to carry them out efficiently.

Step 3: Familiarize yourself with the DevOps toolchain:

Git: Git, a distributed version control system is extensively utilized by DevOps teams, for code repository management. It aids in monitoring code alterations facilitating collaboration, among team members and preserving a record of modifications made to the codebase.

Ansible: Ansible is an open source tool used for managing configurations deploying applications and automating tasks. It simplifies infrastructure management. Saves time when performing tasks.

Docker: Docker, on the other hand is a platform for containerization that allows DevOps engineers to bundle applications and dependencies into containers. This ensures consistency and compatibility across environments from development, to production.

Kubernetes: Kubernetes is an open-source container orchestration platform that helps manage and scale containers. It helps automate the deployment, scaling, and management of applications and micro-services.

Jenkins: Jenkins is an open-source automation server that helps automate the process of building, testing, and deploying software. It helps to automate repetitive tasks and improve the speed and efficiency of the software delivery process.

Nagios: Nagios is an open-source monitoring tool that helps us monitor the health and performance of our IT infrastructure. It also helps us to identify and resolve issues in real-time and ensure the high availability and reliability of IT systems as well.

Terraform: Terraform is an infrastructure as code (IAC) tool that helps manage and provision IT infrastructure. It helps us automate the process of provisioning and configuring IT resources and ensures consistency between development and production environments.

Step 4: Gain practical experience:

The best way to gain practical experience is by working on real projects and bootcamps. You can start by contributing to open-source projects or participating in coding challenges and hackathons. You can also attend workshops and online courses to improve your skills.

Step 5: Get certified:

Getting certified in DevOps can help you stand out from the crowd and showcase your expertise to various people. Some of the most popular certifications are:

Certified Kubernetes Administrator (CKA)

AWS Certified DevOps Engineer

Microsoft Certified: Azure DevOps Engineer Expert

AWS Certified Cloud Practitioner

Step 6: Build a strong professional network:

Networking is one of the most important parts of becoming a DevOps Engineer. You can join online communities, attend conferences, join webinars and connect with other professionals in the field. This will help you stay up-to-date with the latest developments and also help you find job opportunities and success.

Conclusion:

You can start your journey towards a successful career in DevOps. The most important thing is to be passionate about your work and continuously learn and improve your skills. With the right skills, experience, and network, you can achieve great success in this field and earn valuable experience.

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Google Cloud Professional Cloud Architect Certification. Become a GCP Cloud Architect, Latest GCP Exam and Case Studies.

Google Cloud Platform is one of the fastest-growing cloud service platforms offered today that lets you run your applications and data workflows at a 'Google-sized' scale.

Google Cloud Certified Professional Cloud Architect certification is one of the most highly desired IT certifications out today. It is also one of the most challenging exams offered by any cloud vendor today. Passing this exam will take many hours of study, hands-on experience, and an understanding of a very wide range of GCP topics.

Luckily, we're here to help you out! This course is designed to be your best single resource to prepare for and pass the exam to become a certified Google Cloud Architect.

Why should do a Google Cloud Certification?

Here are few results from Google's 2020 Survey:

89% of Google Cloud certified individuals are more confident about their cloud skills

GCP Cloud Architect was the highest paying certification of 2020 (2) and 2019 (3)

More than 1 in 4 of Google Cloud certified individuals took on more responsibility or leadership roles at work

Why should you aim for Google Cloud - GCP Cloud Architect Certification?

Google Cloud Professional Cloud Architect certification helps you gain an understanding of cloud architecture and Google Cloud Platform.

As a Cloud Architect, you will learn to design, develop, and manage robust, secure, scalable, highly available, and dynamic solutions to drive business objectives.

The Google Cloud Certified - Professional Cloud Architect exam assesses your ability to:

Design and architect a GCP solution architecture

Manage and provision the GCP solution infrastructure

Design for security and compliance

Analyze and optimize technical and business processes

Manage implementations of Google Cloud architecture

Ensure solution and operations reliability

Are you ready to get started on this amazing journey to becoming a Google Cloud Architect?

So let's get started!

Who this course is for:

You want to start your Cloud Journey with Google Cloud Platform

You want to become a Google Cloud Certified Professional Cloud Architect

[innovativeacademy-blog]

Quiz Time

Visit: https://innovativeacademy.in Call us: +91 8447712333

[lokeshtsofttech]

Tsofttech is a One of the best quality training center for online, Classroom and Corporate trainings In Hyderabad . We are providing DEVOPS Online Training through world wide. Tsofttech is excellent DEVOPS Training center in Hyderabad. After course we will give support for certification, Resume preparation and how to prepare for interviews.

For More: https://tsofttech.com/devops-online-training

Attend Free Demo On DevOps With AWS Sign Up Now: https://bit.ly/3rp0W84 To Boost Your IT Career to Next Level by Expert Faculty's. Register now to reserve your spot.

[wicultyls]

Exclusive Training institute for AWS and many courses | Wiculty

Wiculty’s AWS training and certification will help you master skills like AWS Cloud, Lambda, Redshift, EC2, IAM, S3, Global Accelerator and more. Also, in this AWS course, you will work on various tools of AWS cloud platform and create highly scalable SaaS application. Learn AWS from AWS certified experts to become an AWS solutions architect.Download CurriculumFree Linux & Shell Scripting Course

[mousumi93]

Web Hosting 101: An Introduction to the Basics for Beginners

Web hosting is a service that allows individuals and organizations to make their website accessible on the internet. A web host, also known as a hosting provider, stores the files that make up a website on servers that are connected to the internet. When a user types in a website’s URL into their browser, the request is sent to the server where the website is hosted, and the server then sends the website’s files back to the user’s browser to be displayed.

There are different types of web hosting available, including shared hosting, virtual private servers (VPS), and dedicated hosting. (Read More)

[dgruploads]

AWS | Episode 3 | Types of infrastructure | Understanding different types of infrastructure

[arrowpc-network]

Simplifying Your Journey: AWS Cloud Migration with Arrow PC Network

In today's digital age, businesses are increasingly turning to cloud solutions to leverage scalability, flexibility, and cost-effectiveness. As a trusted technology partner, Arrow PC Network is committed to assisting enterprises in unlocking the full potential of cloud computing. This blog post explores the benefits and best practices of AWS cloud migration through the lens of Arrow PC Network, showcasing their expertise in seamlessly transitioning businesses to the cloud

The Power of AWS Cloud:

The AWS cloud is a leading provider of on-demand cloud computing resources, offering a wide range of services, including compute power, storage, databases, analytics, machine learning, and more. Arrow PC Network recognizes the transformative power of AWS and helps businesses harness this potential to drive innovation, reduce operational costs, and enhance overall efficiency.

Why Migrate to AWS Cloud with Arrow PC Network? :

Arrow PC Network distinguishes itself as an AWS migration partner by providing a comprehensive suite of services tailored to meet the unique needs of each business. From initial planning and assessment to the execution and post-migration support, their certified experts guide businesses through the migration journey with meticulous attention to detail.

Understanding the Business Needs:

Arrow PC Network begins the migration process by understanding the specific requirements and objectives of the business. They work closely with key stakeholders to analyze existing infrastructure, applications, and data to devise a personalized migration strategy that ensures minimal disruption to ongoing operations.

Picking the Right Migration Approach:

There is no one-size-fits-all approach to cloud migration. Arrow PC Network advises businesses on choosing the most suitable migration model, be it a "lift-and-shift" approach for rapid migration or a more complex re-architecting for optimizing performance and cost-effectiveness.

Data Security and Compliance:

Arrow PC Network prioritizes data security and compliance throughout the migration journey. They implement robust security measures, including encryption, access controls, and continuous monitoring, to safeguard sensitive information and meet industry-specific regulations.

Seamless Application Migration:

Migrating applications to the cloud requires careful planning and execution. Arrow PC Network's seasoned experts utilize automation tools and a phased approach to ensure a smooth transition, reducing the risk of downtime and data loss.

Optimizing Costs and Performance:

One of the primary benefits of cloud migration is cost optimization. Arrow PC Network assists businesses in selecting the most cost-efficient AWS services, right-sizing resources, and leveraging auto-scaling capabilities to achieve maximum performance while keeping operational expenses in check.

Post-Migration Support and Monitoring:

Cloud migration is not a one-time event; it's an ongoing journey. Arrow PC Network provides continuous support and monitoring to address any post-migration challenges, ensuring that the migrated environment remains secure, performant, and scalable.

Conclusion :

As businesses continue to embrace the cloud as a key driver of innovation and growth, Arrow PC Network stands as a reliable partner in guiding organizations through the complexities of AWS cloud migration. Their expertise, combined with a deep understanding of individual business needs, empowers enterprises to leverage the full potential of AWS and embark on a successful cloud journey.

Let Arrow PC Network be your trusted companion on your path to digital transformation with AWS cloud migration.

linkedin.com/in/karanjot-singh - Cloud Expert at Arrow PC Network

[qualitythought]

Do you want to upskill your career in Amazon Web Services (AWS)? Join our AWS Job-oriented intensive program. We have both Online & Offline Training. Attend Free Live Demo on 13th Feb 2023 at 9:00am

🌐Register for the Course: https://www.qualitythought.in/registernow 📲 contact: 99637 99240 📩 Telegram Updates: https://t.me/QTTWorld 📧 Email: info@qualitythought.in Facebook: https://www.facebook.com/QTTWorld/ Instagram: https://www.instagram.com/qttechnology/ Twitter: https://twitter.com/QTTWorld Linkedin: https://in.linkedin.com/company/qttworld ℹ️ More info: https://www.qualitythought.in/

[lavanyachowary]

Navigating AWS: A Beginner's Guide to Cloud Computing

[dgruploads]

Essential AWS Services You Must Learn for Solutions Architect | Complete Guide for 2025