Recreation of issue ElementsProject/lightning#4335

docker-compose.yml

version: "3.9"
services:
  lightningd:
    environment:
      BITCOIND_RPCUSER: rpcuser
      BITCOIND_RPCPASS: rpcpass
      BITCOIND_RPCCONNECT: bitcoind
      BITCOIND_RPCPORT: 8332
    expose:
      - "9375/tcp"
    build:
      context: .
      dockerfile: Dockerfile.lightningd

  bitcoind:
    environment:
      BITCOIND_RPCUSER: rpcuser
      BITCOIND_RPCPASS: rpcpass
      BITCOIND_RPCPORT: 8332
    ports:
      - "8332:8332"
    build:
      context: .
      dockerfile: Dockerfile.bitcoind

Dockerfile.bitcoind

FROM ubuntu:20.04
RUN apt-get update -q \
	&& apt-get install -y -qq --no-install-recommends \
	ca-certificates \
	dirmngr \
	wget \
	curl \
	build-essential

ARG BITCOIN_VERSION=0.20.1
ENV BITCOIN_TARBALL bitcoin-${BITCOIN_VERSION}-x86_64-linux-gnu.tar.gz
ENV BITCOIN_URL https://bitcoincore.org/bin/bitcoin-core-$BITCOIN_VERSION/$BITCOIN_TARBALL
ENV BITCOIN_ASC_URL https://bitcoincore.org/bin/bitcoin-core-$BITCOIN_VERSION/SHA256SUMS.asc
ENV PATH /opt/bitcoin/bin:$PATH

RUN mkdir /opt/bitcoin && cd /opt/bitcoin \
    && wget -qO $BITCOIN_TARBALL "$BITCOIN_URL" \
    && wget -qO bitcoin.asc "$BITCOIN_ASC_URL" \
    && grep $BITCOIN_TARBALL bitcoin.asc | tee SHA256SUMS.asc \
    && sha256sum -c SHA256SUMS.asc \
    && BD=bitcoin-$BITCOIN_VERSION/bin \
    && tar -xzvf $BITCOIN_TARBALL $BD/ --strip-components=1 \
    && rm $BITCOIN_TARBALL

VOLUME /var/run/bitcoind
VOLUME /etc/btc-rpc-proxy/
EXPOSE 8332:8332

cmd bitcoind \
	-rpcuser=$BITCOIND_RPCUSER \
	-rpcport=$BITCOIND_RPCPORT \
	-rpcpassword=$BITCOIND_RPCPASS \
	-server=1 \
	-rpcallowip=0.0.0.0/0 \
	-rpcbind=0.0.0.0:8332

Dockerfile.lightningd

FROM ubuntu:20.04

RUN apt-get update -q \
	&& apt-get install --yes -qq software-properties-common \
	&& add-apt-repository --yes --update ppa:cdecker/clightning \
	&& apt-get install --yes -qq lightningd wget python3 python3-pip \
	&& rm -rf /var/lib/apt/lists/*

ARG BITCOIN_VERSION=0.20.1
ENV BITCOIN_TARBALL bitcoin-${BITCOIN_VERSION}-x86_64-linux-gnu.tar.gz
ENV BITCOIN_URL https://bitcoincore.org/bin/bitcoin-core-$BITCOIN_VERSION/$BITCOIN_TARBALL
ENV BITCOIN_ASC_URL https://bitcoincore.org/bin/bitcoin-core-$BITCOIN_VERSION/SHA256SUMS.asc

RUN mkdir /opt/bitcoin && cd /opt/bitcoin \
	&& wget -qO $BITCOIN_TARBALL "$BITCOIN_URL" \
	&& wget -qO bitcoin.asc "$BITCOIN_ASC_URL" \
	&& grep $BITCOIN_TARBALL bitcoin.asc | tee SHA256SUMS.asc \
	&& sha256sum -c SHA256SUMS.asc \
	&& BD=bitcoin-$BITCOIN_VERSION/bin \
	&& tar -xzvf $BITCOIN_TARBALL --strip-components=1 \
	&& rm $BITCOIN_TARBALL
ENV PATH /opt/bitcoin/bin:$PATH


CMD bitcoin-cli -rpcconnect=$BITCOIND_RPCCONNECT -rpcuser=$BITCOIND_RPCUSER -rpcpassword=$BITCOIND_RPCPASS -rpcport=8332 -rpcwait echo hi