Docker

What is Docker?

Docker uses (Linux) kernel features and puts the known chroot concept on steroids. This way we can get a universal system to build and ship applications. Docker is the popular implementation, which has informed the OCI- specification and given rise to other runtimes such as Podman.

The technical foundation

The technical foundation topics concerning Docker are:

Container images
- Image registries
Overlay file systems
Linux kernel features: namespaces, cgroups, capabilities
Network bridge interfaces
Routes and IPtables
Build environments
Execution environments
- operating system (usually a minimal Linux) and runtime dependencies (of a release build)

In addition:

Possibly virtualization (for example, when Docker is used on Microsoft Windows with Docker Desktop)
Possibly orchestration technology (such as Kubernetes)
Continuous Integration (Jenkins, GitHub Actions etc.) and Continouus Deployment schemes
- DevOps automation
…

Although Docker is one technology element within a DevOps stack, it belongs to the bigger topic of MicroService architectures. Such architectures can have organizational dependencies, related to team management and organization.

What is Cloud Native?

Cloud Native denotes a macro trend related to the standardization of Linux service management and Linux-based cloud computing. It’s when services are made for the cloud (including on-premises private cloudsas defined within NIST 800-145). Cloud Native services can be migrated between different kinds of cloud deployment scenarios, which may help with a defined onboarding, migration and exit strategy of the services in scope.