14.1.3 Production Host Readiness
A focused guide to Production Host Readiness, connecting core concepts with practical Docker and container operations.
Production host readiness assesses whether the actual machine (or fleet of machines) running Docker in production is itself properly configured and maintained — an up-to-date Docker Engine, adequate disk space, appropriate monitoring — since even a perfectly configured container can suffer from an underlying host-level problem.
Why the Host Itself Is Part of Production Readiness
A container's own configuration doesn't protect against a host running out of disk space, an outdated Docker Engine with known issues, or insufficient host-level monitoring to even notice a problem occurring.
docker version
df -h /var/lib/docker
Checking these directly against the actual host reveals whether basic host-level readiness concerns have actually been addressed.
Keeping the Docker Engine Itself Up to Date
Running a current, supported Docker Engine version ensures access to bug fixes, security patches, and ongoing vendor support.
docker version --format '{{.Server.Version}}'
Ensuring Adequate, Monitored Disk Space
Docker's own storage — images, containers, volumes, build cache — consumes host disk space that needs to be monitored and periodically reclaimed.
docker system df
docker system prune -af --filter "until=168h"
Confirming Host-Level Monitoring and Alerting Actually Exists
Verifying that host-level metrics (CPU, memory, disk) are actually being collected and alerted on, not just assumed to be, closes an important gap host readiness specifically needs to address.
curl http://localhost:9100/metrics
Why Production Host Readiness Matters
A container's careful configuration provides no benefit if the underlying host it's running on isn't itself properly maintained and monitored — host readiness is a distinct, necessary layer of the overall production readiness assessment.