Containers require changes to the way security policies are implemented and managed. Security should be built into the container lifecycle as much as possible, using a DevSecOps approach. Security teams, working with development and operations teams, adapt existing governance and compliance policies to accommodate new tools and changes to the application lifecycle. 

Manual effort slows down development teams. Container automation enables developers to focus on code instead of packaging. Container images are built in layers. With an automated approach to container builds, whenever a layer changes, only that layer has to be updated. For example, if only system libraries need to be updated, only the layer containing the libraries must be rebuilt. Because other layers remain unchanged, the testing and validation burden is reduced, enabling updated containers to be pushed into production faster and more frequently. 

Since its introduction in 2013, Docker has been almost synonymous with containers, and it continues to be used to build container images. The Docker environment includes a container runtime as well as container build and image management. Because Docker builds an OCI-standard container image, Docker images will run on any OCI-compliant container runtime. 

For developers

• Improve application portability across different platforms and configurations, so that code developed on one version of a language compiler or interpreter runs flawlessly on subsequent versions with no revisions required.
• Free developers from having to develop, test, and deploy on the same infrastructure, so that developers who write code on their laptops can be confident that application will run as desired on any other infrastructure, whether on-premises server or a cloud-based VM.
• Facilitate agile development processes such as CI/CD, speeding code acceptance and deployment.

For IT operations

• Improve application security by isolation from other applications in a lightweight fashion.
• Seamless migration of containerized applications across different OS versions, network topologies, or storage configurations, and cloud platforms.
• Improve IT efficiency by enabling multiple application containers to run on a single OS instance. Since containers are often tens of megabytes in size where VMs are often ten or more gigabytes in size, a substantially larger number of containers can run on a single server instance. 

Deliver extreme on-demand scalability, by spinning up additional container instances in milliseconds versus minutes to spin up VMs.