.net core!! - first program - on Mac

What is software configuration management, SCM, CM?

                              Software Configuration Management

History

What is SCM

Modules of SCM

Configuration Manager

History:

US dept. of defense maintain and operates tons of verities of military equipment’s. Obviously it’s tedious if you don’t have a system to track and maintain the items. So they approached Software Engineering Institute (CMU) to develop a better process to track, maintain, status etc. of military inventories. It’s SEI and other groups of industry experts developed CMMI/SCM. Actually SCM is part of CMMI. CMMI contains 22 process areas, all these process talks about how to improve SDLC life cycle from requirement to deployment (complete SDLC). CMMI model can be adopted to other non-software industry as well.  

Here onwards I specifically talk about SCM (for software / IT).

Basically what SEI and others they did was, gathered all of existing knowledge/experience of software development/any other industry. They gone through day to day activities of configuration management, pointed out main tasks, etc. Out of this knowledge/experience and forethoughts they developed a process called SCM.

Main idea behind the Process is to reuse the existing knowledge of a domain(software or any), refine, improve and follow it. (In other words, don’t re-invent the wheel)

Processes are key for success of any project because, every individual have different thoughts so it creates confusion. “Process brings order out chaos”.

What is SCM:

 “The purpose of Configuration Management (CM) is to establish and maintain the integrity of work products using configuration identification, configuration control, configuration status accounting, and configuration audits. “– CMMI.  I know its bit vague, since SCM can be adopted by other industry’s they defined it in generic term.

Simplified, the purpose of SCM is:

Identify all the documents (design, test plan …), source code, software’s/hardware related to a project.

          Control accidental release of software into prod/QA, prioritize the bugs …

            Status approved changes, revision history, change logs, change request records …

            Audit basically to check, whether your project actually follows CM process according to SCM standard.

SCM, is involved in entire SDLC. At first people think it’s just a source code control/repository but it’s beyond. It involves from requirement to deployment. Don’t believe me, here you go:

a          Document’s repository (requirements, designs, project plans, test plan, release plan, deployment plan…)

b          Source control/repository

c          Build management (branching / merging / baseline / backup the source code)

d          Release management

e          Deployment management

Typical SCM, in a project looks like this: A configuration manager he or she will be responsible for overall CM related activities like to create a CM plan, build plan, release plan, conduct CM audits and to spread the CM process knowledge across the team.

Agile development methodology has introduced the term called Continuous integration / Continuous deployment, basically they are fine-tuned version\variation or lean version of SCM process.

Govt. projects like space, army, medical… they fully adhere to SCM and they can’t do fast phased development like typical IT projects, because of product criticality like life and death.  So there is no one fit size for all, some will follow lean scm and few typical cmmi scm.

Modules of SCM:

Typical SCM modules occupy a book, but I try to explain briefly main modules of SCM are:

Document repository: SCM manages all the project related documents for ex: project plan, test plan … here process tracks versions/stages of docs like from draft to approve what changed, doc version numbers etc. usually docs will be stored separate doc repository for ex: share point and not in source control.

CM Plan: It’s a document which describes over all CM activities, like who is the CM, where is source code located and its path, docs repository path, audit plans, build/release activities. CM plan might have reference to build/release plans. Basically if any outsider looks into this doc he or she should able to figure out about project CM activities.

Source code management: Source control like TFS, SVN, Git are used to store the source code. It’s were all the project related code will exist. From here developers will check in or out.

Build systems: It’s a system / box where code will be pulled from source control and do build of a project every night or as soon as user checks in source code.

Change control: typically consist of product stake holders, PM, CM … to control the change request to project.

Release management: is process where you define how to push source code\binaries, bundle and deploy to Prod or QA. It also contains release notes, known bugs\issues.

Audits:  checks whether,  users are checking the code with proper comment\issue number, code backups are taken, process mentioned in the doc and followed are matching etc.

Configuration (Release) Manager:

He or She will be responsible for overall CM related activities inside a project. Its full time or part time job based on the project scale. I try to briefly point out the CM roles and responsibility:

a)    After project initiation CM activities will start

b)    Create CM plan, co coordinating with PM, Tech lead, project stake holders

c)    Over all in charge or admin of source control. CM decides who and what access will users will have. Only few of team members can have admin access to source control

d)    Creates build plan \ system. Plan will have at what frequency build will should happen, a unique id for the build, whether to push binaries to specific location or not and many other things

e)    Release management, package creation, release notes …

f)     Spreading the CM process awareness among the team members. By presentation, demos …

Summary:

You like it or hate it, but you can’t ignore SCM. Waterfall, Agile, Spiral … they all follow one way or other a CM process.

How web works - simplified

Internet, is network of computers, from outside it looks very complex but internally it works on few simple principles. Here principles I mean standards/protocols like HTTP, TCP/IP, html and also laws of electromagnetism (in simple, its law of light. it’s very important for internet, because all of the data will be travelling near to speed of light otherwise internet will be very slow. Trick here is whatever web request or response will be converted into binaries and send them via wave pattern inside optic cables)

Before I explain components of web. I just like to mention how standards or protocols helps to develop such complex systems. Standards like HTTP is nothing but a few set of rules on which two system will interact seamlessly because both the system know what is the rules/standard/language. For ex: when traffic signal light is red we stop, green go. Same way web browser and web server both have knowledge about HTTP and its language.

So basically when you click on a link on web browser, it talks to a remote web server and gets back the data what you have asked for and displays it on browser.

Following are the key components of the web, together they make internet work. Each one of them is big enough to accommodate a book or more. So I will try to explain each one briefly and hope easy to understand. Actually there are lot more components like DNS, OSI models, Firewall, and others involved in to make internet work but for us to understand how web works below items are good enough.

HTTP, Transport Layer (TCP/IP), Web Server, ISP, Browser, HTML5 (structure),

CSS3 (presentation), JavaScript (interactivity)

Browser: First thing first, browser is a software/window to internet through which user browse the web. How can it talk to remote server, get data like text, picture, video, and display? Answer is HTTP, html … Browser is a software/program built on standards/protocols like http, html, css, javascript.  For ex: when browser sees content like make me bold it render/display like “make me bold”, so it’s nothing rocket science. All the standards or rules of http, html… are already coded inside software to how to display text, make calls remote server, etc.

HTML, CSS, JavaScript: these are language of web. HTML is for structuring the data, CSS to present the data and JavaScript for interaction or behavior. Just html is enough for to display data but it will very dull and boring. To give life to web CSS, JS came to existence. When Tim (legend) invented the web he just thought to link the documents and access it over network (I am simplifying itJ). He had no idea one day web will explode so big like what we see today.

HTTP: hypertext transport protocol, is an application protocol. Web browser/client sends http request to web server and web server returns http response and content as html. HTTP has specified different way to request and response. Here are the http methods : HEAD, GET, POST, PUT, DELETE, TRACE … don’t worry if you don’t get it, these are verbs or actions clients request to server for ex: HEAD means header of http request/response, GET means get a resource from web server, POST means get or create a list of resource in the server. So this is how server know how to respond if any request comes from client.

TCP/IP: Transporting of http bundle to web server involves lot of behind the scene actors like OSI models ( its seven layer of network,  it defines how data will travel from your computer to Ethernet to cable to computer next to you or other side of the world). But in that layer TCP/IP is important for us to understand how http request will be get pocketed, addressed, transported and received.  This layer is very important because activities like 3 way handshake and other connection establishment all this will happen less then fraction of second. (Thanks to speed of lightJ)

ISP: is network of thousands of miles fiber optic cable, spread across intercontinental or via satellite. Its organization provides internet access. Through which all your web request and response will travel.

Web Server: As name says its serve the web request. The server is just a software not the computer. Like web browser, server is also a program coded to understand HTTP methods and respond accordingly to http request. Basically server will respond with documents, images, videos, etc. Web server may be right next door or across ocean.

Summary: Web/internet is very exciting place. Its part and parcel of our life now. Its topic of worth many books, but I just thought briefly dot the maps and present brief idea about web to users. I might have missed to explain few points or explain in more detail, it’s just because to simplify. Thanks!

Cloud Computing - Demystified

Agenda:

To understand basics of Cloud Computing and it flavors

Walkthrough IaaS a type of Cloud computing

Walk through layers of IaaS

Introduction VMware vSphere / Microsoft Hyper V

Pros/Cons

References/further studies

Basics of Cloud Computing and it flavors

Cloud computing is a system for enabling convenient, on-demand network access to a shared pool of configurable computing resources e.g., servers, storage, applications/softwares, and services that can be quickly provisioned(is term used in IT to setup and ready to use) and released with minimal user effort or service provider interaction.

If you google about cloud computing you see similar description all over the internet. Let’s break it down. In earlier days, network designers while modeling network plan they used to mention cloud diagram for unknown/somebody else problem/work. When you/company/govt. anybody needs a pool of computing resources like a computers, software, storage (photos, videos remember iCloud or google drive), you can approach cloud service providers like amazon, Microsoft and many others. Once you approach them and using their applications/websites within few minutes you can set up your computing resources. 

So when you don’t want rent office space, hire network engineers, buy computers upfront, less capital … solution is cloud computing.

I know still many grey areas about cloud computing, let’s get into detail of it. Here is the trick/how cloud service providers do the magic of providing cloud computing services on demand (means when you need it start using it and when you don’t stop/cancel the service). Data Centers: is huge building, inside you see hundreds of blade servers, storage racks, virtual servers, network setups … usually data centers will be setup strategically(geographically, environmentally). Typically with one data center cloud provider can provide service to hundreds of customers.

In brief, log in to cloud provider website, register and with few button clicks from your office/home couch you can setup a computing resources. Isn’t ridiculously simple?

Flavors of Cloud: There are many jargons used inside cloud computing like SaaS, PaaS, IaaS,… these are all slightly different services provided over network to end customers. Let’s look into them briefly

SaaS (Software as a Service): You got married, photographer took excellent photos but you still you feel to do little touch up to your photos. So will you buy photo editing software paying upfront $$$ just to edit pics, after that you won’t use it or just rent it for a day get done your work and just pay fraction of $? Obviously later, that’s it that is the Software as a Service, pay per use. All you have do is login to SaaS provider website pay per use and exit. Isn’t it cool?

PaaS (platform as a Service): It’s a computing resource with windows, linux or mac platform. Within few clicks of button on service provider website, a virtual machine will be ready for you, all you need is internet and you can login to that vm from your laptop or desktop.

IaaS (Infrastructure as a Service): a pool of virtual/physical machines, storage, networks. This flavor we shall discuss in brief later sections.

You got a wonderful startup idea, but you don’t have computers, required software’s and also lot of money. With little money and help of cloud service providers you can set up 10 to 20 computers, software’s with less time and start implementing your ideas. If successful continue the service, worst case you can turn of cloud services.

Ex: Amazon EC2, Microsoft Azure, Office 365, Outlook365, Gmail for organization, Salesforce...

Walkthrough IaaS

IaaS or Computing as a Service is basic Cloud computing service. It is the first thing we can think of when somebody talks about cloud computing. In fact researcher at Cambridge first developed virtual machine software called Xen. Basically idea of virtual machine is simple, On top of hardware/OS, a hypervisor layer sits which helps to create virtual machines in which we can install different OS and run parallel in a box. Hypervisor software takes advantage of modern powerful hardware which at any point of time won’t be consumed by user, so creates an abstract layer and distributes/shares computing resources across multiple virtual machines.

IaaS: can be pool of virtual machines/physical machines, storage, servers, network… IaaS provider will take care of security/patch updates to the virtual/physical machines, on demand computing power increase/decrease (RAM, Processors)

  

Walk through layers/internals of IaaS

         Here is what typical work flow looks like inside a cloud company/datacenter, when you or an organization requests for computing resources from cloud service provider. Its number sequential work flows as follows.

  UI Layer: First you will land in cloud provider website. User interface/web site where customers login from their location, and create/update cloud service request. For ex: you are starting up a new business and you need 5 computers(virtual machines). Just login like www.cloudprovider.com.

  Business Logic Layer:  Once user submits his/her request like how many virtual machines, software’s, operating system(platforms) they need. Business layer where they have hardware, software stock details in DB. Number of business logics will trigger and instantly give feedback to customer that how much time/minutes will take to complete their request via UI. Business layer does many checks like enough blade server available or not, storage and many other tasks before invoking workflow engine.

  Orchestration/Work Flow Engine: After updating the user about request status, business layer passes client request to work flow engine. Which will have algorithms to execute clients request sequentially, ex: first create virtual machine, install OS, applications like ms office… if any step fails it will update system/db and exits. Some major cloud vendors provide work flow engine live status so that they can what’s going on.

  Virtual Machine Management Center: Hypervisor(like VMware, MS Azure..) creates virtual machines. Usually scripts will exists, workflow engine just invokes it and script will does all the activities like, create, update VMs, installing a server automation client inside VM…

Hypervisor is one of the key component of cloud computing, because most of the cloud request is for virtual machines.  Hypervisor provides excellent client\UI to monitor and control the virtual machines, through which we can know whether a partical VM is up or down, status of it. Using client you can increase ram, processor, … I am just mentioned few feature of hypervisor but it does lot of other complex tasks like clustering, if a VM goes down, automatically another VM boots up its called high availability …

  Server Automation: as name says it does many server related activities like installing OS in VM, patch’s/security updates.

  Network Management: set up network/vLan, IP management and other network related activities.

Above mentioned points/steps involves complex tasks, I am just trying to simply and give an idea what goes on inside a Datacenter. Each steps have separate dedicated team, hundreds of scripts to execute automatically in synchronized way and its team work, together they make cloud work.

Introduction VMware vSphere / Microsoft Hyper V

Pros:

·        No upfront investment for infrastructure like servers, software’s, storage, network. Pay per use.

·        No worries about security/patch updates. Cloud service provider will take care of it.

·        On demand computing resource increase or decrease, for ex: increase RAM, Processor when required and later turn it off

Cons:

·        You will be locked with one service provider, it’s very hard to migrate to different provider in current cloud architecture

·        Availability. Even cloud giants experience network/service outages.         

·        Internet connectivity. No internet no cloud

·        Long term cloud seems more expensive than in house server setup.

References

https://azure.microsoft.com/en-us/get-started/

https://aws.amazon.com/what-is-cloud-computing/?nc2=h_l2_cc

I recommend you to go through above links, they have very good tutorials and documentation. If you like to become AWS / Azure developer it takes some time to get your feet wet, but you can learn and start developing programs with in short span of time. Writing small or simple programs is key to understand a new concept