Docker / Compose, Swarm & Production Security
Investigate a Compose scale-up blocked by fixed host ports
Several replicas cannot normally bind the same host address and port on one daemon. Inspect current publications and the service design.
Environment and inputs: Docker Engine · Compose v2 and Buildx where specified; Linux containers unless noted. Verify daemon context, installed feature support and authorized host or Swarm manager access first.
Start with this check
Confirm the environment and replace sample objects, namespaces, images, paths and hosts with approved targets. Share only relevant, sanitized output. Follow the workload owner’s process for changes.
docker compose psRead the result
The project summary exposes current service instances and published ports. It does not prove the model supports multiple replicas or an external load balancer.
Resolve and verify
Compare fixed bindings, container-name settings and intended routing with the supported scale design. Use a reviewed proxy or allocation model and validate each replica.
Before changing production
Do not remove required isolation or stop another workload simply to make a second replica claim its port.