Under the Hood

Under the Hood

Contributing projects:

Under the Hood

dockerd

• API endpoint
• Integration with ecosystem
• Automation
• Based on Moby
• Offers certificate authentication
• Talks to containerd using gRPC

containerd

• Distribution (push/pull)
• Container management
• Storage
• Belongs to CNCF
• Implements OCI image specification
• Donated by Docker

runc

• Isolates processes
• Interacts with kernel
• Lightweight
• Belongs to OCI (Linux Foundation)
• Implements OCI runtime specification
• Donated by Docker in 2015

Under the Hood

Processes:

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Demo: Under the Hood

Separate dockerd and containerd:

docker run -d --name dind --privileged docker:stable-dind
docker exec -it dind sh
ps

Use containerd independently:

ctr --address /run/docker/containerd/containerd.sock image pull docker.io/library/docker:stable
ctr --address /run/docker/containerd/containerd.sock image ls

Images are stores separately:

docker image ls