RDS related error when deploying a Docker Rails 6 app to AWS ECS

Question

I am trying to deploy a Rails 6 app to AWS ECS.

The deployment fails, and I got the following error:

health_check failed: Plugin http could not be loaded: Error loading shared library lib/mariadb/plugin/http.so: No such file or directory

Gemfile

gem 'rails', '~> 6.0.0'
gem 'mysql2'

Gemfile.lock

mysql2 (0.5.3)
rails (6.0.3.6)

I am not using MariaDB in my app, but according to the mysql2 gem author, it might be necessary to add MariaDB dependencies .

You may need to install a package such as libmariadb-dev, libmysqlclient-dev, mysql-devel, or default-libmysqlclient-dev; refer to your distribution's package guide to find the particular package. The most common issue we see is a user who has the library file libmysqlclient.so but is missing the header file mysql.h -- double check that you have the -dev packages installed.

Dockerfile

###############################
FROM ruby:2.6.3-alpine

ARG RAILS_ENV
ENV RAILS_ENV ${RAILS_ENV}

RUN apk add --update --no-cache \
  build-base \
  openssl \
  mysql-dev \
  mariadb-dev \
  git \
  tzdata && \
  cp /usr/share/zoneinfo/Asia/Tokyo /etc/localtime

WORKDIR /app
ADD Gemfile* /app/

RUN gem install --no-document bundler
RUN bundle install -j4 --retry 3 \
  && rm -rf /usr/local/bundle/cache/*.gem \
  && find /usr/local/bundle/gems/ -name "*.c" -delete \
  && find /usr/local/bundle/gems/ -name "*.o" -delete

# Add the Rails app
ADD . /app

WORKDIR /app

CMD ["bundle", "exec", "puma", "-C", "config/puma.rb"]

I built my app with:

docker-compose build --no-cache

Any help would be highly appreciated.

Answer 1

The error was related to the DB address format.

To make it work, I removed the http:// prefix and the trailing / to the DB address env variable.

I changed:

DB_HOST=http://abcdef-rds.xyz.ap-northeast-1.rds.amazonaws.com/

to:

DB_HOST=abcdef-rds.xyz.ap-northeast-1.rds.amazonaws.com