What is Agile Software Development?

Software development methodologies centered round the idea of iterative development, where requirements and solutions evolve through collaboration between self-organizing cross-functional teams.

Why agile? 

Agile development is that it enables teams to deliver value faster, with greater quality and predictability, and greater aptitude to respond to change.

Agile Manifesto: 4 Value & 12 Principals (http://agilemanifesto.org)

Values:

• Individuals and interactions over processes and tools
• Working software over comprehensive documentation
• Customer collaboration over contract negotiation
• Responding to change over following a plan

12 Principals:

First Principle (is the Key):  Commitment to value delivery: “Highest priority is to satisfy the customer through early and continuous delivery of valuable software.”

What is DevOps ?

DevOps = Development(Dev) + Operation(Ops)

A cultural shift or movement that encourage great collaboration between Dev and Ops team to build (building, testing, and releasing software) quality software more quickly with more reliability

NOTE: DevOps is NOT a “Set of Tools” or Standards 

What's the difference between Agile and DevOps?

DevOps Concepts

Build Automation & SCM = Reliable Builds

• Faster Builds – Less manual step, faster execution time
• Consistent – Same way every time means more predictability
• Repeatable – Same code can be rebuild multiple times with same results
• Portable – Can be executed on any machine

Continuous Integration (CI)

• Practice of frequently merging code instead of a mass merge excursive
• Detecting problems earlier
• Should be automated as much as possible

Continues Deployment (CD)

• Practice of continuously maintaining code in deployable state to ensure that the software can be reliably released at any time.
• Actual deployment time is purely a business decision

Continues Delivery (CD)

• A practice of continuously deploying small changes to production
• Deployment is a routine and reliable rollbacks and is automated
• Faster time to market
• Fewer number of changes in each deployment means less risk

Infrastructure as code (Configuration Management)

• Managing infrastructure and provisioning resources through code and automation
• Automatized configuration changes and less configuration drift
• Faster response time
• Reliable
• Repeatable
• Self documenting

Orchestration

• Automation of process/workflows to respond to the infrastructure needs
• Increase demand = create more nodes
• Monitor resources and automate to respond to requirement change

DevOps Periodic Table

https://digital.ai/periodic-table-of-devops-tools

DevOps Practice 

What are some known DevOps practices?

• Canary Releases
• Dark Launches
• Automated Provisioning
• Infrastructure as Code
• Small frequent changes
• Version Control
• Continuous Integration (including automated testing)
• Continuous Delivery / Release Management
• Measuring metrics

Now Lets look at DevOps definition again – (There is No single definition)

“DevOps is a union of people, process, and products to enable continuous delivery of value to end users”

What are some Key DevOps Indicators & Measurements

Velocity KPIs

• MLT (Mean Lead Time)
  How long does it take for a bit of code to get built, tested and deployed?
• DCR (Daily Change Rate)
  Number of changes getting committed to mainline and tested per day.
• MTTE (Mean Time To Environment)
  How much time it takes developers/testers to bring up a testing environment for verifying each delivered change.
• MTTD (Mean Time to Detect)
  How much time passes since the original commit of code until the bug it introduces gets detected.
• MTTR (Mean Time To Resolve)
  How much time it takes to resolve an issue after it’s detected
• MTTA (MeanTime To Approve)
  How much time it takes to approve and verify a release.

Quality KPIs

• BFR (Build Failure Rate)
   Percentage of failed builds
•  DFR (Deployment Failure Rate)
   Percentage of failed deployments
• IRFR (Infrastructure-Related Failure Rate)
   Percentage of build/deployment failures related to infrastructure issues
• RWR (Rework Rate)
   Percentage of tickets being reopened
• ADR (Automated Detection Rate)
   Percentage of defects being detected by automated testing cycles
• UWR (Unplanned Work Rate)
   Percentage of unplanned issues