Demystifying DevOps

DevOps team

That takes care of the entire SDLC life cycle - build deploy and monitor.

Component of DevOps infinity loop

• Plan

• Code

• Build

• Test

• Release

• Deploy

• Operate

• Monitor

Objective of DevOps

To automate repeatable tasks as much as possible.

Continuous Integration (CI)

• Frequently merging codes changes from multiple developers into a repo

• Automated build and test are run to provide real-time feedback]

• Aim :- To minimize bugs within the code early within the cycle

Continuous Delivery (CD)

• Ship software to production environment.

• CD pipeline -> build changes -> packages -> run integration and system tests.

• After approval -> deploy changes to your test & production environments.

Infrastructure as Code (IAC)

• Managing and provisioning infrastructure using code and configuration files.

• Build infrastructure through API calls and templates.

Configuration as code (CaC)

• Managing and provisioning configuration settings using code and version control systems.

Monitoring and logging

• Involves capturing and analyzing data about the behavior and performance of software applications and systems.

• Aim:- to identify issues, troubleshoot problems and make informed decisions for improvement.

Cloud-native applications

• Scalability, flexibility and resilient (fault-tolerant)

• Microservices architecture

• Containerization :- consistent, portable, lightweight environment for applications to run; Build once, run anywhere and the Package once, deploy anywhere

  • Contains required libraries and dependencies.

  • Containers do not inherit the OS environment variables, we have to set them separately.

  • Containers were designed to use Linux namespaces to provide isolation and cgroups to offer restrictions on CPU, memory, and disk I/O consumption.

• Dynamic orchestration.

Containers

• Consistent, portable, lightweight environment for applications to run; Build once, run anywhere and the Package once, deploy anywhere

• Contains required libraries and dependencies.

• Containers do not inherit the OS environment variables, we have to set them separately.

• Containers were designed to use Linux namespaces to provide isolation and cgroups to offer restrictions on CPU, memory, and disk I/O consumption.

• Container networking

  • SDN :- Software-defined networks.

  • None :- Fully isolated network; assigned to loopback interface.

  • Bridge :- default network in most container runtimes

    • Uses docker0 interface.

    • NAT between the container and host network - allows external network connectivity.

    • Does not result in port conflict.

    • multiple containers can use the same container port.

    • Containers can communicate within single host using container IP address.

    • Best practice :- Don't bridge network for clustered configuration.

  • Host

    • Ues the network namespace of the host machine for all the containers.

    • Prone to port-conflict issues

    • No network isolation between container (a potential security issue)

  • Underlay

    • Underlay exposes the host network interfaces directly to containers.

    • Example :- assign a MAC address to every container.

  • Overlay

    • Overlay networks allow communication between containers on different host machines via a networking tunnel.

  • Containers inherit the host OS's DNS settings

  • Docker containers do not inherit entries in the /etc/hosts files

• Container build and deployment workflow

  • Code app.

  • Create a Dockerfile - contains steps to install application dependencies and environment configurations.

  • Using Dockerfile

    • Build container image.

    • Run container image.

    • Unit test the app running on the container.

  • Push image to registry.

  • Create containers from container images.

• Migration to containers?

  • Stateless relative easy to containerize.