The summary.
WHAT CONTAINERS SOLVE
Software behaving differently between environments, by guaranteeing the same contents wherever it runs.
WHAT THEY DO NOT SOLVE
Bad architecture, the need for monitoring and backups, or complexity — which they add.
Most small businesses do not need them.
IF YOU BUILD IMAGES
Pin the base version, include only what runs, and never pass secrets at build time — anything included remains in the image even if later removed.
Run as a non-administrative user, and tag every image traceably to a commit.
ORCHESTRATION INTRODUCES MORE FAILURE MODES THAN IT REMOVES AT SMALL SCALE
Ask what problem it solves that simpler options cannot, and who operates it when its champion leaves.
Most applications never outgrow one well-configured server.
THE ENVIRONMENT DIFFERENCE THAT BAFFLES PEOPLE MOST
Filename case sensitivity. Developing where case is ignored and deploying where it is not produces failures nobody diagnoses quickly.
TEST WITH REALISTIC DATA VOLUME
Performance problems appear only then, and never in development with three records.
