1,298
Learners
verifying this skill
2,756
Sessions
completed to date
70
Avg SCI
across all levels
4
Tiers
claimed → peer-endorsed
In a peer session, write Dockerfiles, debug container networ
In a peer session, write Dockerfiles, debug container networking issues, or design multi-container architectures.
Your partner evaluates your understanding of image layers, v
Your partner evaluates your understanding of image layers, volumes, networking modes, and production best practices.
Rated evidence commits to your passport and builds your Dock
Rated evidence commits to your passport and builds your Docker SCI.
Docker — facts worth knowing.
Docker was released in 2013 by Solomon Hykes at dotCloud. The open-source release at PyCon 2013 was so unexpectedly popular that it briefly crashed the company's GitHub repository.
Did you know?
A minimal Alpine Linux base image for Docker is only 5MB – compared to Ubuntu at ~70MB. Image size discipline is one of the first things separating Docker beginners from experts.
Did you know?
The OCI (Open Container Initiative) specification was created to standardize container formats and runtimes – meaning containers created with Docker can run with Podman, containerd, or any other OCI-compliant runtime.
Did you know?
Why Docker matters.
Docker changed how software is built, shipped, and deployed by packaging applications and their dependencies into portable containers. Understanding Docker means understanding image layers, networking, volumes, and the full container lifecycle. Lemma sessions test whether you can use it in production, not just on your laptop.
Docker is a required skill for virtually every backend, DevOps, and platform engineering role. The gap between basic Docker usage and genuine expertise is large – knowing when to use multi-stage builds, how to minimize image surface area, and how to debug networking issues. Lemma surfaces that expertise gap.
1,298 people are learning this on Lemma
2,756 peer sessions completed
Avg SCI of 70 — tier 3 practitioners
avg SCI on Lemma
Docker practitioners
Related skills
Docker verification — common questions
In a peer session, you write Dockerfiles, debug container networking, or design multi-container architectures. Your partner evaluates your understanding of layers, volumes, networking, and production best practices.
Your Docker SCI measures proficiency in image optimization, multi-stage builds, container networking, volume management, security hardening, and composing multi-service applications with Docker Compose.
Yes. Container fundamentals are a prerequisite for Kubernetes. If you have not verified Docker, start there. Kubernetes sessions assume you understand images, containers, and basic networking at a professional level.
Common topics include multi-stage build optimization, layer caching strategy, COPY vs ADD, network mode selection, secret management, and the difference between CMD and ENTRYPOINT.
DCA is a proctored exam testing broad Docker knowledge. Lemma verification proves hands-on container skills through live peer sessions with recorded evidence of your actual work and reasoning.
Start verifying your Docker skills.
Join the waitlist. Your first peer session is free.