Docker
docker.comDevOps
Still the default way to package an app so it runs the same everywhere — the container format everyone else standardized on.
Other products from DevOps
The de facto IaC standard — declarative HCL and a provider ecosystem so broad you'll rarely hit something it can't provision.
Runs most of the internet's containers, but respect the learning curve — nobody accidentally becomes good at YAML manifests.
IaC in real programming languages instead of a bespoke DSL — good if hand-writing HCL makes you twitchy.
Agentless config management over plain SSH — playbooks read like English until you need a loop inside a loop.