How to SSH into Docker containers

A Docker container is a portable software package that includes an application’s code, dependencies, and environment settings, allowing for easy execution and troubleshooting. To diagnose issues in a Docker container, Secure Shell (SSH) can be used for secure access, though this requires an SSH server, potentially increasing the container's size and complexity. Alternatively, the docker exec command offers a more lightweight method for executing commands within running containers, making it ideal for quick diagnostics during development and testing. While SSH provides a secure connection, docker exec allows for direct interaction with the container’s shell, facilitating tasks such as installing utilities or checking environmental variables. This approach is particularly useful in CI/CD pipelines, where understanding and resolving build failures quickly is essential. CircleCI supports integrated SSH access, enhancing the ability to troubleshoot and recover from issues efficiently in various execution environments, including Docker.