Containers provide a predictable, replicable way to run applications by isolating software from its environment, increasing consistency and reliability across development and staging environments. Container isolation is achieved through various mechanisms like control groups, secure computing mode filters, kernel namespaces, sandbox containers, and virtualized containers. Best practices for security and methodology vary depending on the container type, including Linux containers, sandboxed containers, and lightweight virtual machines. Key considerations include performance, security, complexity, and development time when choosing a container isolation approach. Employing best practices such as using dedicated users, limiting capabilities, blocking unneeded network devices, and configuring kernel parameters can help reduce the attack surface of containers. Additionally, developer-first approaches like using code scanners and container scanners to keep content secure are essential for maintaining container security.