Github Host key verification Failing - docker

Question

I am trying to add Github.com as known_hosts file for this docker file but somehow I believe www-data is failing to get access to known_hosts file. Code below is the complete docker file. Specific git error is
Failed to execute git clone --mirror --
Host key verification failed.
fatal: Could not read from remote repository.
Please make sure you have the correct access rights.
and the repository exists.
FROM php:7.4-fpm as base
ENV COMPOSER_HOME=/tmp/composer
ENV APCU_VERSION=5.1.18
RUN apt-get update && apt-get install -y --no-install-recommends gnupg \
netcat \
sudo \
libicu-dev \
libfreetype6-dev \
libjpeg-dev \
libpng-dev \
libsodium-dev \
libxml2-dev \
libxslt-dev \
libzip-dev \
rsync \
unzip \
git \
openssh-client \
;
RUN pecl install apcu-${APCU_VERSION}
RUN docker-php-ext-configure gd --enable-gd --with-freetype --with-jpeg
RUN docker-php-ext-install -j "$(nproc)" \
bcmath \
gd \
intl \
mysqli \
opcache \
pdo_mysql \
sockets \
soap \
xsl \
zip \
;
RUN docker-php-ext-enable apcu
RUN echo "memory_limit=1G" >> /usr/local/etc/php/conf.d/zz-memory-limit-php.ini
RUN echo "apc.enable=1" >> /usr/local/etc/php/conf.d/zz-apcu.ini
RUN echo "apc.enable_cli=1" >> /usr/local/etc/php/conf.d/zz-apcu.ini
RUN echo "opcache.memory_consumption=512MB" >> /usr/local/etc/php/conf.d/zz-opcache.conf
RUN echo "opcache.max_accelerated_files=60000" >> /usr/local/etc/php/conf.d/zz-opcache.conf
RUN echo "opcache.consistency_checks=0" >> /usr/local/etc/php/conf.d/zz-opcache.conf
RUN echo "opcache.validate_timestamps=0" >> /usr/local/etc/php/conf.d/zz-opcache.conf
RUN echo "opcache.enable_cli=1" >> /usr/local/etc/php/conf.d/zz-opcache.conf
FROM base as build
RUN curl https://files.magerun.net/n98-magerun2.phar -o /usr/local/bin/magerun \
&& chmod 755 /usr/local/bin/magerun
RUN mkdir -p /root/.ssh && \
chmod 0700 /root/.ssh && \
ssh-keyscan -t rsa github.com >> /root/.ssh/known_hosts
USER www-data
WORKDIR /var/www/html
ARG COMPOSER_AUTH
COPY --from=composer:2 /usr/bin/composer /usr/bin/composer
COPY --chown=www-data composer.json composer.json
COPY --chown=www-data composer.lock composer.lock
RUN php -d memory_limit=2G $(which composer) install --no-progress --no-dev
COPY --chown=www-data app/etc/config.php app/etc/config.php
COPY --chown=www-data bin bin
FROM build as app
ENV MAGE_MODE=production
RUN php -d memory_limit=2G bin/magento setup:di:compile
RUN composer dump-autoload --optimize --apcu
RUN php -d memory_limit=2G bin/magento setup:static-content:deploy -f
RUN rm -rf /var/www/html/var/cache
RUN rm -rf /var/www/html/var/page_cache
RUN rm -rf /var/www/html/var/session
COPY --chown=www-data app/etc/env.docker.php app/etc/env.php

Answer 1

ssh will verify the key of the other server. It cannot confirm that the key presented by the server is trusted, so it fails.
ssh-keygen -R domain.com
ssh-keyscan -t rsa domain.com >> ~/.ssh/known_hosts
The authenticity of host 'domain.com (a.b.c.d)' can't be established.
RSA key fingerprint is XX:XX:...:XX.
Are you sure you want to continue connecting (yes/no)?
A: yes

Answer 2

Please contact your system administrator. Add correct host key in /home/user01/. ssh/known_hosts to get rid of this message.