Docker BuildKit, multi-stage builds, rootless mode, distroless images, and Docker Desktop alternatives — from June 2026 community discussions.

Docker Hot Topics: June 2026

From r/docker, HN, and Docker Discord (6k messages). The 5 most-discussed questions.

1. “My image is 1.2GB, how do I shrink it?”

The top r/docker thread (1.1k upvotes) — common answer: multi-stage builds + distroless base.

Bad (1.2GB):

FROM node:20
RUN npm install
COPY . .
CMD ["npm", "start"]

Good (180MB):

# Build stage
FROM node:20-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build

# Runtime stage
FROM gcr.io/distroless/nodejs20-debian12
COPY --from=builder /app/dist /app
CMD ["/app/index.js"]

2. “Docker Desktop is heavy — alternatives?”

HN (890 points): Podman + Lima on macOS, buildah on Linux. Rootless, no daemon.

brew install podman lima
limactl start
podman run --rm hello-world

3. “Multi-stage builds vs BuildKit cache mounts”

Use --mount=type=cache for package managers:

RUN --mount=type=cache,target=/root/.npm npm ci

This caches node_modules between builds — 5x faster rebuilds.

4. “Rootless Docker — should I use it?”

Production: yes. Dev: not yet (debugging pain). The Docker Discord poll showed 40% use rootless in prod, 12% in dev.

5. “Distroless images — what are they?”

Distroless = no shell, no package manager, just your app. Smaller attack surface, smaller images. Used by Google, Microsoft internally.

Sources

r/docker: 1.1k upvotes
HN: 890 points
Docker Discord: 6k messages

Docker Hot Topics: 5 Real Questions from r/docker and HN