Security is a recurring concern when packaging and running shared workloads. Docker Content Trust, abbreviated DCT, is a mechanism that signs images with cryptographic keys so that consumers can verify both the integrity and the publisher of an image during push and pull operations. You enable it by exporting the environment variable DOCKER_CONTENT_TRUST=1, after which Docker refuses to pull or run images that are not properly signed.
Beyond trust, the most serious class of risk is the container breakout, a vulnerability in which a process running inside a container escapes its isolation and gains access to the host system. Breakouts typically exploit weaknesses in the kernel or misconfigured privileges. Defending against them requires following well-known best practices: build images from minimal bases, run containers as a non-root user via the USER instruction, scan images for known vulnerabilities using tools like Trivy, drop unnecessary Linux capabilities, and keep the host kernel up to date. Combined with content trust, these habits significantly reduce the attack surface of a containerized deployment.
When something does go wrong, Docker provides a layered set of diagnostic tools. docker logs container prints the standard output and error streams of a container, which is usually the first place to look. docker inspect returns detailed JSON metadata about a container, image, volume, or network and is invaluable for understanding configuration. docker exec lets you open a shell inside a running container to investigate the live filesystem and processes, while docker events provides a real-time stream of daemon activity. Checking resource limits, reviewing health status from HEALTHCHECK results, and cross-referencing logs with compose or service output together form a reliable workflow for resolving most container issues.