> For the complete documentation index, see [llms.txt](https://hanfak.gitbook.io/workspace/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hanfak.gitbook.io/workspace/devops1/deployment.md).

# Deployments

* stage of the software development lifecycle
* involves the process of making a software application or system available and operational on a specific environment or infrastructure.
* It typically includes tasks such as installing, configuring, and running the software on servers, cloud platforms, or other computing environments.
* Deployment focuses on the technical aspects of getting the software up and running.
* During deployment, developers and operations teams work together to ensure that the application is properly installed, the necessary dependencies are satisfied, and the system is ready to serve end users.
* Deployments can be performed multiple times during the development cycle, particularly during iterative development and continuous integration/continuous deployment (CI/CD) practices.

## Stages

* Planning:
  * defining the deployment strategy, including determining the target environment, infrastructure requirements, and deployment timeline.
  * It may also involve coordinating with different teams, such as development, operations, and testing, to align on the deployment plan.
* Building and Packaging:
  * the software application is built, compiled, and packaged into a distributable format.
  * tasks such as code compilation, asset generation, and creating executable files or containers.
  * Can be done before deployment (ie as part of a CI)
* Configuration and Environment Setup:
  * The deployment environment, including servers, databases, networking, and other infrastructure components, is prepared and configured to support the software application.
  * includes setting up
    * appropriate configurations
    * installing dependencies
    * ensuring compatibility between the application and the environment
* Testing:
  * Can be optional, if done before
    * ie as part of CI, all parts are tested and an artifact is produced and versioned which will be the candidate to be deployed
  * Before deploying the software to production, it is crucial to perform testing to verify its functionality, performance, and stability.
  * This can involve various types of testing, such as unit testing, integration testing, regression testing, and user acceptance testing (UAT).
  * Testing helps identify and resolve any issues or bugs that may impact the deployment.
* Deployment Execution
  * involves actually deploying the software to the target environment.
  * Depending on the deployment strategy, this can be a manual or automated process.
    * Manual deployment may involve transferring files, running installation scripts, or configuring the software manually.
    * Automated deployment often utilizes tools and frameworks like CI/CD pipelines to streamline the process, ensuring consistency and reducing human error.
* Verification and Validation:
  * Once the software is deployed, it is important to validate that the deployment was successful and the application is functioning as expected.
  * This may involve performing
    * additional tests
    * monitoring system behavior
    * comparing the deployed version against predefined criteria or acceptance criteria.
    * runnign a smoke test (automated or manaul)
    * checking the status page is up and passing
    * checking logs are showing no errors
* Rollback and Recovery
  * In case any issues or unexpected problems arise during or after the deployment, having a rollback plan is important.
  * Rollback involves reverting to a previous version or configuration to mitigate the impact of a failed deployment.
  * Additionally, recovery plans should be in place to address any potential downtime, data loss, or service disruptions.
* Post-Deployment Activities
  * After the successful deployment, there are often additional tasks to perform,
  * updating documentation
  * notifying stakeholders about the new version
  * monitoring system performance
  * gathering feedback from end users
* These activities help ensure that the deployed software is well-maintained and any necessary improvements or bug fixes are addressed in subsequent releases.