Dockerfile.docker

#
# NOTE: THIS DOCKERFILE IS GENERATED VIA "apply-templates.sh"
#
# PLEASE DO NOT EDIT IT DIRECTLY.
#

FROM ubuntu:20.04

RUN apt update \
    && apt install -y ca-certificates openssh-client wget

# set up nsswitch.conf for Go's "netgo" implementation (which Docker explicitly uses)
# - https://github.com/docker/docker-ce/blob/v17.09.0-ce/components/engine/hack/make.sh#L149
# - https://github.com/golang/go/blob/go1.9.1/src/net/conf.go#L194-L275
# - docker run --rm debian:stretch grep '^hosts:' /etc/nsswitch.conf
RUN echo 'hosts: files dns' >> /etc/nsswitch.conf

ENV DOCKER_CHANNEL=stable \
  DOCKER_VERSION=20.10.8
# TODO ENV DOCKER_SHA256
# https://github.com/docker/docker-ce/blob/5b073ee2cf564edee5adca05eee574142f7627bb/components/packaging/static/hash_files !!
# (no SHA file artifacts on download.docker.com yet as of 2017-06-07 though)

RUN set -eux; \
	\
	arch="$(uname --m)"; \
	case "$arch" in \
        # amd64
		x86_64) dockerArch='x86_64' ;; \
        # arm32v6
		armhf) dockerArch='armel' ;; \
        # arm32v7
		armv7) dockerArch='armhf' ;; \
        # arm64v8
		aarch64) dockerArch='aarch64' ;; \
		*) echo >&2 "error: unsupported architecture ($arch)"; exit 1 ;;\
	esac; \
	\
	if ! wget -O docker.tgz "https://download.docker.com/linux/static/${DOCKER_CHANNEL}/${dockerArch}/docker-${DOCKER_VERSION}.tgz"; then \
		echo >&2 "error: failed to download 'docker-${DOCKER_VERSION}' from '${DOCKER_CHANNEL}' for '${dockerArch}'"; \
		exit 1; \
	fi; \
	\
	tar --extract \
		--file docker.tgz \
		--strip-components 1 \
		--directory /usr/local/bin/ \
	; \
	rm docker.tgz; \
	\
	dockerd --version; \
	docker --version

COPY modprobe.sh /usr/local/bin/modprobe
COPY docker-entrypoint.sh /usr/local/bin/

# https://github.com/docker-library/docker/pull/166
#   dockerd-entrypoint.sh uses DOCKER_TLS_CERTDIR for auto-generating TLS certificates
#   docker-entrypoint.sh uses DOCKER_TLS_CERTDIR for auto-setting DOCKER_TLS_VERIFY and DOCKER_CERT_PATH
# (For this to work, at least the "client" subdirectory of this path needs to be shared between the client and server containers via a volume, "docker cp", or other means of data sharing.)
ENV DOCKER_TLS_CERTDIR=/certs
# also, ensure the directory pre-exists and has wide enough permissions for "dockerd-entrypoint.sh" to create subdirectories, even when run in "rootless" mode
RUN mkdir /certs /certs/client && chmod 1777 /certs /certs/client
# (doing both /certs and /certs/client so that if Docker does a "copy-up" into a volume defined on /certs/client, it will "do the right thing" by default in a way that still works for rootless users)

ENTRYPOINT ["docker-entrypoint.sh"]
CMD ["sh"]