Continuous Integration vs Continuous Delivery vs Continuous Deployment

Question

What s the difference between these three terms  My university provides the following definitions   Continuous Integration basically just means that the developer s working copies are synchronized with a shared mainline several times a day   Continuous Delivery is described as the logical evolution of continuous integration  Always be able to put a product into production   Continuous Deployment is described as the logical next step after continuous delivery  Automatically deploy the product into production whenever it passes QA   They also provide a warning  Sometimes the term  Continuous Deployment  is also used if you are able to continuously deploy to the test system   All this leaves me confused  Any explaination that is a little more detailed  or comes with an example  is appreciated

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From what I ve learned with Alex Cowan in the course Continuous Delivery  amp  DevOps  CI and CD is part of a product pipeline that consists in the time it goes from an Observations to a Released Product     From Observations to Designs the goal is to get high quality testable ideas  This part of the process is considered Continuous Design   What happens after  when we go from the Code onwards  it s considered a Continuous Delivery capability whose aim is to execute the ideas and release to the customer very fast  you can read Jez Humble s book Continuous Delivery  Reliable Software Releases through Build  Test  and Deployment Automation for more details   The following pipeline explains which steps Continuous Integration  CI  and Continuous Delivery  CD  consist of     Continuous Integration  as Mattias Petter Johansson explains      is when a software team has habit of doing multiple merges per day and   they have an automated verification system in place to check those   merges for problems     you can watch the following two videos for a more pratical overview using CircleCI - Getting started with CircleCI - Continuous Integration P2 and Running CircleCI on Pull Request    One can specify the CI CD pipeline as following  that goes from New Code to a released Product     The first three steps have to do with Tests  extending the boundary of what s being tested   Continuous Deployment  on the other hand  is to handle the Deployment automatically  So  any code commit that passes the automated testing phase is automatically released into the production   Note  This isn t necessarily what your pipelines should look like  yet they can serve as reference

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Continuous Integration  I Agree with your university s definition  Continuous Integration is a strategy for how a developer can integrate code to the mainline continuously - as opposed to frequently   You might claim that it s merely a branching strategy in your version control system   It has to do with the size of the tasks you assign to a developer  If a task is estimated to take 4-5 man-days then the developer will have no incitement to deliver anything for the next 4-5 days  because he s not done with anything - yet   So size matters   small task   continuous integration big task     frequent integration   The ideal task size is not bigger than a day s work  This way a developer will naturally have at least one integration per day   Continuous Delivery  There are basically three schools within Continuous Delivery   Continuous Delivery is a natural extension of Continuous Integration  This school  looks at the Addison-Wesley  Martin Fowler  signature series and makes the assumption that since the 2007 release was called  Continuous Integration  and the one that followed in 2011 was called  Continuous Delivery  they are probably volume 1 2 of the same conceptual idea that has to do with continuous something   Continuous Delivery has to do with Agile Software Development  This school takes off-set in the idea that Continuous Delivery is all about being able to support the principles in the agile movement  not just as a conceptual idea or a letter of intent but for real - in real life   Taking offset in the first principle in the Agile Manifesto where the term  continuous delivery  is actually used for the first time      Our highest priority is to satisfy the customer through early and continuous delivery of valuable software    This school claims that  Continuous Delivery  is a paradigm that embraces everything required to implement an automated verification of your  definition of done    This school accepts that  Continuous Delivery  and the buzz word or megatrend  DevOps  are flip sides of the same coin  in the sense that they both try to embrace or encapsulate this new paradigm or approach and not just a technique   Continuous Delivery is a synonym to Continuous Deployment  The third school advocates that Continuous Deployment and Continuous Delivery can be used interchangeably to mean the same thing   When something is ready in the hands of the developers  it s immediately delivered to the end-users  which in most cases will mean that it should be deployed to the production environment  Hence  Deploy  and  Deliver  means the same   Which school to join  Your university clearly joined the first school and claims that we re referring to volume 1 2 of the same publication series  My opinion is that this is a misuse of the term Continuous Delivery   I personally advocate for the understanding that Continuous Delivery is related to implementing a real-life support for the ideas and concepts stated by the agile movement  So I joined the school that says the term embraces a whole paradigm - like  DevOps    The school that uses delivery as a synonym to deploy is mostly advocated by tool vendors who create deployment consoles  trying to get a bit of hype from the more widespread use of the term Continuous Delivery   Continuous Deployment  The focus on Continuous Deployment is mostly relevant in domains where the end user s access to software updates relies on the update of some centralized source for this information and where this centralized source is not always easy to update because it s monolithic or has  too  high coherence by nature  web  SOA  Databases etc     For a lot of domains that produces software where there is no centralized source of information  devices  consumer products  client installations etc   or where the centralized source for information is easy to update  app stores artifact management systems  Open Source repositories etc    there is almost no hype about the term Continuous Deployment at all  They just deploy  it s not a big thing - it s not a pain that requires special focus   The fact that Continuous Deployment is not something that is generically interesting to everyone is also an argument that the school that claims that  delivery  and  deploy  are synonyms got it all wrong  Because Continuous Delivery actually makes perfectly good sense to everyone - even if you are doing embedded software in devices or releasing Open Source plugins for a framework   Your university s definition that Continuous Deployment is a natural next step of Continuous Delivery implicitly assumes that every delivery that is QA ed should go become available to the end-users immediately  is closer to the definition that my tribe use to describe the term  Continous Release   which  in turn  is another concept that doesn t generically makes sense to everyone either   A release can be a very strategic or political thing and there is no reason to assume that everybody would want to do this all the time  unless they are an online bookstore a streaming service type of company   Nevertheless  companies that don t blindly release everything all the time may have any number of reasons why they would want to be masters of deployment anyway  so they too do Continuous Deployment  Not of release to production  but of release-candidates to production-like environments   Again I believe your university got it wrong  They are mistaking  Continuous Deployment  for  Continuous Release    Continuous deployment is simply the discipline of continuously being able to move the result of a development process to a production-like environment where functional testing can be executed in full scale   The Continuous Delivery Storyline  In the picture it all comes alive     The Continuous Integration process is the first two actions in the state-transition diagram  which - if successful - kicks off the Continuous Delivery pipeline that implements the definition of done   Deployment is just one of the many actions that will have to be done continuously in this pipeline  Ideally  the process is automated from the point where the developer commits to the VCS to the point where the pipeline has confirmed that we have a valid release candidate

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Continuous Integration basically just means that the developer s working copies are synchronized with a shared mainline several times a day    Or more than several times per day   As often as any given discrete task is completed  basically   Consider for example a team of developers working on a single business application   In many environments  the following may happen    One or two developers keep local changes for a few days because  it s not ready yet   One or two developers create branches in the source control so they can work on their feature s   without being bothered by other people s changes     These can lead to problems   Poor code task organization leads to branching  branching leads to merging  merging    leads to suffering   Continuous integration as a practice addresses this by encouraging everybody to work from the same shared source   Individual work items should be discrete enough to be completed in a short amount of time  hours at most    Basically the general idea is that integrating a small change in a small amount of work   Integrating a large change is a disproportionately large amount of work   The aggregate of integration work is smaller if done in constant small steps   This allows developers to spend more time working on business-visible features instead of development process overhead      Continuous Delivery is described as the logical evolution of continuous integration  Always be able to put a product into production    This follows the same idea of discrete  well defined work items   If there s a single master codebase which is only ever adjusted in small increments by complete  tested  known working features then that codebase is always stable   Automated testing is key here to be able to prove that stability at the push of a button   The less stabilization work that needs to be done  which  again  is development process overhead and should be eliminated   the more often that codebase can be pushed to any given environment   In a lot of companies a deployment can be a pretty grueling process   Even a week-long all-hands-on-deck operation   This is expensive and produces no business value   By employing good work item definitions  effective automated testing  and continuous integration a team can be in a position to automate the codebase s delivery to any given environment      Continuous Deployment is described as the logical next step after continuous delivery  Automatically deploy the product into production whenever it passes QA    You ll rarely see this happen in a business environment  and it s quite a joy when it s encountered   If the codebase can be automatically tested and automatically deployed to any given environment then  well  production is an environment like any other   So if the team has built up to this point then there s a potential for significant value to the business by always being able to deploy updates to production   Defect fixes are sent to customers faster  new features reach the market faster  new ideas are tested against the market in smaller increments to allow for redirection of priorities  etc   For example  let s say a company has a big idea for a new feature in their software-based product or service   They ve done some research  they know the market  and they believe this idea will result in a strong new line of revenue   Now consider two options for delivering that feature    Spend months developing the whole thing in a one-off branch   Spend weeks integrating it back into the main codebase   Spend days testing it   Spend a day deploying it   And only then start tracking actual revenue in the production system  Implement small parts of the feature  one at a time   Each week release a new piece of it   Each week get more data on actual revenue    In the first scenario  if the feature doesn t have the desired market effect then a lot of money is wasted on something customers don t actually want   In the second scenario the fact that customers don t want it is determined much  much earlier and the rest of the work is de-prioritized     Ultimately these  continuous things  are all about removing development process overhead   If a company s line of revenue is a particular service offering then ideally all of their costs should go into that offering   Development process overhead  merging code  re-testing the same features after a merge  manual deployment tasks  etc   don t actually contribute to the value of the service  so these concepts seek to remove those costs from the process

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One graph can replace many words     Enjoy   -     I have updated the correct image

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Difference between Continuous Integration  Continuous delivery and continuous deployment

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Continuous Integration  The practice of merging the development work with the main branch constantly so that the code has been tested as often as possible to catch issues early    Continuous Delivery  Continuous delivery of code to an environment once the code is ready to ship  This could be staging or production  The idea is the product is delivered to a user base  which can be QA s or customers for review and inspection    Unit test during the Continuous Integration phase can not catch all the bugs and business logic  particularly design issues that is why we need QA  or staging environment for testing    Continuous Deployment  The deployment or release of code as soon as it s ready  Continuous Deployment requires Continuous Integration and Continuous Delivery otherwise the code quality won t be guarantee in a release   Continuous Deployment    Continuous Integration   Continuous Delivery

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Continuous Integration   Automated building of check ins   unit test    Continuous Delivery    Continuous Integration Automated deployment to test environment   load testing   integration test  Manual deployment to production    Continuous Deployment   Continuous Delivery but automated deployment to production    CI CD is a journey  Not a destination       These stages are suggestions  You can adapt the stages based on your   business need  Some stages can be repeated for multiple types of   testing  security  and performance  Depending on the complexity of   your project and the structure of your teams  some stages can be   repeated several times at different levels  For example  the end   product of one team can become a dependency in the project of the next   team  This means that the first team   s end product is subsequently   staged as an artifact in the next team   s project    Footnote    Practicing Continuous Integration and Continuous Delivery on AWS

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lets keep it short    CI  A software development practice where members of a team integrate their work at least daily  Each integration is verified by automated build  include tests to detect error as quick as possible  CD  CD Builds on CI  where you build software in such a way that the software can be released to production at any time

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Source  https   thenucleargeeks com 2020 01 21 continuous-integration-vs-continuous-delivery-vs-continuous-deployment  What is Continuous Integration Continuous Integration is a process or a development practice of automated build and automated test i e  A developer is required to commit his code multiple times into a shared repository where each integration is verified by automated build and test  If the build fails success it is notified to a developer and then he can take relevant actions  What is Continuous Delivery Continuous Delivery is the practise where we keep our code deployable at any point which has passed all the test and has all the required configuration to push the code to production but hasn   t been deployed yet  What is Continuous Deployment With the help of CI we have created s build for our application and is ready to push to production  In this step our build is ready and with CD we can deploy our application directly to QA environment and if everything goes well we can deploy the same build to production  So basically  Continuous deployment is one step further than continuous delivery  With this practice  every change which passes all stages of your production pipeline is released to your customers  Continuous Deployment is a combination of Configuration Management and Containerization  Configuration Management  CM is all about maintaining the configuration of server which will be compatible to application requirement  Containerization  Containerization is a set of tolls which will maintain consistency across the environment   Img source  https   www atlassian com

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DevOps is a combination of 3C s - continuous  communication  collaboration and  this lead to prime focus in various industries   In an IoT connected devices world  multiple scrum features like product owner  web  mobile and QA  working in an agile manner in a scrum of scrum cycle to deliver a product to end customer      Continuous integration  Multiple scrum feature working simultanrouly in multiple endpoints      Continuous delivery  With integration and deployment  delivery of product to multiple customers to be handled at the same time       Continuous deployment  multiple products deployed to multiple customers at multiple platform    Watch this to know how DevOps enabling IoT connected world  https   youtu be nAfZt2t4HqA

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I think amazon definition is straight and simple to understand    Continuous delivery is a software development methodology where the release process is automated  Every software change is automatically built  tested  and deployed to production  Before the final push to production  a person  an automated test  or a business rule decides when the final push should occur  Although every successful software change can be immediately released to production with continuous delivery  not all changes need to be released right away   Continuous integration is a software development practice where members of a team use a version control system and integrate their work frequently to the same location  such as a master branch  Each change is built and verified by tests and other verifications in order to detect any integration errors as quickly as possible  Continuous integration is focused on automatically building and testing code  as compared to continuous delivery  which automates the entire software release process up to production    Please check out http   docs aws amazon com codepipeline latest userguide concepts html

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I think we re over analyzing and maybe complicating a bit the  continuous  suite of words  In this context continuous means automation  For the other words attached to  continuous  use the English language as your translation guide and please don t try to complicate things   In  continuous build  we automatically build  write compile link etc  our application into something that s executable for a specific platform container runtime etc   Continuous integration  means that your new functionality tests and performs as intended when interacting with another entity   Obviously  before integration takes place  the build must happen and thorough testing would also be used to validate the integration  So  in  continuous integration  one uses automation to add value to an existing bucket of functionality in a way that doesn t negatively disrupt the existing functionality but rather integrates nicely with it  adding a perceived value to the whole  Integration implies  by its mere English definition  that things jive harmoniously so in code-talk my add compiles  links  tests and runs perfectly within the whole  You wouldn t call something integrated if it failed the end product  would you   In our context  Continuous deployment  is synonymous with  continuos delivery  since at the end of the day we ve provided functionality to our customers  However  by over analyzing this  I could argue that deploy is a subset of delivery because deploying something doesn t necessarily mean that we delivered  We deployed the code but because we haven t effectively communicated to our stakeholders  we failed to deliver from a business perspective  We deployed the troops but we haven t delivered the promised water and food to the nearby town  What if I were to add the  continuous transition  term  would it have its own merit  After all  maybe it s better suited to describe the movement of code through environments since it has the connotation of  from to  more so than deployment or delivery which could imply one location only  in perpetuity  This is what we get if we don t apply common sense   In conclusion  this is simple stuff to describe  doing it is a bit more    complicated    just use common sense  the English language and you ll be fine

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Atlassian posted a good explanation about Continuous integration vs  continuous delivery vs  continuous deployment     In a nutshell   Continuous Integration - is an automation to build and test application whenever new commits are pushed into the branch   Continuous Delivery - is Continuous Integration   Deploy application to production by  clicking on a button   Release to customers is often  but on demand    Continuous Deployment - is Continuous Delivery but without human intervention  Release to customers is on-going

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Neither the question nor the answers really fit my simple way of thinking about it   I m a consultant and have synchronized these definitions with a number of Dev teams and DevOps people  but am curious about how it matches with the industry at large   Basically I think of the agile practice of continuous delivery like a continuum   Not continuous  everything manual  0  ----  100  Continuous Delivery of Value  everything automated   Steps towards continuous delivery   Zero   Nothing is automated when devs check in code    You re lucky if they have compiled  run  or performed any testing prior to check-in    Continuous Build  automated build on every check-in  which is the first step  but does nothing to prove functional integration of new code  Continuous Integration  CI   automated build and execution of at least unit tests to prove integration of new code with existing code  but preferably integration tests  end-to-end   Continuous Deployment  CD   automated deployment when code passes CI at least into a test environment  preferably into higher environments when quality is proven either via CI or by marking a lower environment as PASSED after manual testing   I E   testing may be manual in some cases  but promoting to next environment is automatic  Continuous Delivery  automated publication and release of the system into production   This is CD into production plus any other configuration changes like setup for A B testing  notification to users of new features  notifying support of new version and change notes  etc    EDIT  I would like to point out that there s a difference between the concept of  continuous delivery  as referenced in the first principle of the Agile Manifesto  http   agilemanifesto org principles html  and the practice of Continuous Delivery  as seems to be referenced by the context of the question   The principle of continuous delivery is that of striving to reduce the Inventory waste as described in Lean thinking  http   www miconleansixsigma com 8-wastes html    The practice of Continuous Delivery  CD  by agile teams has emerged in the many years since the Agile Manifesto was written in 2001   This agile practice directly addresses the principle  although they are different things and apparently easily confused

[continuous-integration] Continuous Integration vs. Continuous Delivery vs. Continuous Deployment

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