Running several containers together.
WHAT IT PROVIDES
A file describing several services, run with one command.
WHAT IT SUITS
Local development Small single-host deployments Testing environments
WHAT IT DOES NOT SUIT
Several hosts Automatic recovery across machines
WHAT THE FILE DESCRIBES
Services, each with an image or build Ports Volumes Environment Networks Dependencies between services
WHAT DEPENDS-ON ACTUALLY DOES
Controls start order, not readiness.
WHY THAT DISTINCTION MATTERS
A database container starting is not a database accepting connections.
WHAT TO DO ABOUT IT
Health checks, with dependants waiting for healthy status Or applications that retry their connections
WHAT TO PREFER
Applications that retry.
WHY
They then survive the database restarting later, not only at startup.
WHAT THE ESSENTIAL COMMANDS ARE
Start everything, in the background Stop and remove View logs across services Execute a command in one service Rebuild
WHAT TO BE CAREFUL WITH
Removing volumes when tearing down, which deletes data.
WHAT TO KEEP SEPARATE
Development and production files, with overrides.
WHAT TO NEVER PUT IN THE FILE
Real credentials.
