Docker and Kubernetes are complementary technologies used for containerized application management, each serving distinct roles within the software development lifecycle. Docker is a suite of tools for creating, sharing, and running containers, which package application code and dependencies in a portable format, allowing applications to run consistently across various environments. Kubernetes, on the other hand, is an orchestration platform that automates the deployment, scaling, and management of these containerized applications, making it ideal for handling complex, distributed systems at scale. While Docker Swarm offers basic orchestration capabilities, Kubernetes is favored for its flexibility, scalability, and extensive ecosystem, supported by major cloud providers and an array of open-source tools for monitoring and security. Together, Docker and Kubernetes enhance application scalability, portability, and security, streamlining continuous integration and delivery (CI/CD) processes and facilitating agile innovation. Despite their strengths, both platforms face challenges in orchestration, such as container deployment, scaling, networking, observability, and security, which require robust solutions and a comprehensive DevSecOps approach.