Docker Application Deployment
A realistic container deployment case study: package an application, define services declaratively, expose only required ports, persist state intentionally, and verify the application from both the container and host perspectives.
APPLICATION SCOPE
The example stack uses an application container plus a database or supporting service. Configuration is separated from the image, secrets are not hard-coded, and persistent data is mounted deliberately.
IMAGE & NETWORK DESIGN
The Dockerfile focuses on a small runtime image and predictable startup. Compose provides service discovery, dependency relationships, environment configuration, health checks, and named volumes.
COMMANDS & OPERATIONS
The operational workflow is build → inspect → start → test → observe → update. Commands below use a harmless demo service and avoid destructive cleanup commands.
$ docker compose config --quiet # configuration valid $ docker compose up -d [+] Running 2/2 ✔ Container demo-app Started ✔ Container demo-db Started $ docker compose ps NAME SERVICE STATUS ... app Up ... db Up
$ docker inspect --format '{{.State.Health.Status}}' demo-app
healthy
$ curl -I http://127.0.0.1:8080/health
HTTP/1.1 200 OK
$ docker compose logs --tail=12 app
<application startup and request lines>VALIDATION
Validation checks container status, published ports, application HTTP responses, logs, health state, and persistence across a controlled restart. This is where many 'works on my machine' issues become visible.
LESSONS LEARNED
Containers simplify packaging but do not remove operational responsibilities. Image provenance, resource limits, logging, updates, backups, and secret handling remain part of the deployment.