rails/capistoranoでデプロイ実行でpumaが起動しない

Question

ローカルのVagrantからcapistoranoでさくらVPSにデプロイをしようとしています。
LoadError: libmysqlclient.so.18が出てきてpumaが起動しません。
参考ファイルは以下に添付します。ご教授お願いします。

deploy.rb

# config valid for current version and patch releases of Capistrano
lock "~> 3.10.1"

set :application, "rails_api"
set :repo_url, "https://github.com/tomoyoshi-de/rails_api.git"

# Default branch is :master
ask :branch, `git rev-parse --abbrev-ref HEAD`.chomp

# Default deploy_to directory is /var/www/my_app_name
set :deploy_to, "/var/www/rails_api"

# Default value for :format is :airbrussh.
# set :format, :airbrussh

# You can configure the Airbrussh format using :format_options.
# These are the defaults.
# set :format_options, command_output: true, log_file: "log/capistrano.log", color: :auto, truncate: :auto

# Default value for :pty is false
# set :pty, true

# Default value for :linked_files is []
append :linked_files, "config/database.yml", "config/secrets.yml", 'config/cable.yml'

# Default value for linked_dirs is []
append :linked_dirs, "log", "tmp/pids", "tmp/cache", "tmp/sockets", "public/system"

set :rbenv_ruby, '2.5.0'

set :puma_pid, "#{shared_path}/tmp/pids/puma.pid"

namespace :puma do
  desc 'Create Directories for Puma Pids and Socket'
  task :make_dirs do
    on roles(:app) do
      execute "mkdir #{shared_path}/tmp/sockets -p"
      execute "mkdir #{shared_path}/tmp/pids -p"
    end
  end
  before :start, :make_dirs
end

namespace :deploy do
  after :restart, :clear_cache do
    on roles(:web), in: :groups, limit: 3, wait: 10 do
      # Here we can do anything such as:
      # within release_path do
      #   execute :rake, 'cache:clear'
      # end
    end
  end
end

namespace :upload do
    %w(database secrets cable).each do |name|
      desc "upload config/#{name}.yml"
      task :"#{name}" do
        on roles(:app), in: :sequence do |host|
          execute :mkdir, '-p', "#{shared_path}/config"
          upload!("config/#{name}.yml","#{shared_path}/config/#{name}.yml")
        end
      end
    end
end
  
# Default value for default_env is {}
# set :default_env, { path: "/opt/ruby/bin:$PATH" }

# Default value for local_user is ENV['USER']
# set :local_user, -> { `git config user.name`.chomp }

# Default value for keep_releases is 5
# set :keep_releases, 5

# Uncomment the following to require manually verifying the host key before first deploy.
# set :ssh_options, verify_host_key: :secure

Capfile

# Load DSL and set up stages
require "capistrano/setup"

# Include default deployment tasks
require "capistrano/deploy"

# Load the SCM plugin appropriate to your project:
#
# require "capistrano/scm/hg"
# install_plugin Capistrano::SCM::Hg
# or
# require "capistrano/scm/svn"
# install_plugin Capistrano::SCM::Svn
# or
require "capistrano/scm/git"
install_plugin Capistrano::SCM::Git

# Include tasks from other gems included in your Gemfile
#
# For documentation on these, see for example:
#
#   https://github.com/capistrano/rvm
#   https://github.com/capistrano/rbenv
#   https://github.com/capistrano/chruby
#   https://github.com/capistrano/bundler
#   https://github.com/capistrano/rails
#   https://github.com/capistrano/passenger
#
# require "capistrano/rvm"
require "capistrano/rbenv"
# require "capistrano/chruby"
require "capistrano/bundler"
#require "capistrano/rails/assets"
require "capistrano/rails/migrations"
# require "capistrano/passenger"
require 'capistrano/puma'

install_plugin Capistrano::Puma

# Load custom tasks from `lib/capistrano/tasks` if you have any defined
Dir.glob("lib/capistrano/tasks/*.rake").each { |r| import r }

エラーメッセージは以下です。
=== puma startup: 2018-01-07 10:13:10 +0900 ===
LoadError: libmysqlclient.so.18: cannot open shared object file: No such file or directory - /var/www/rails_api/shared/bundle/ruby/2.5.0/gems/mysql2-0.4.10/lib/mysql2/mysql2.so
/var/www/rails_api/shared/bundle/ruby/2.5.0/gems/mysql2-0.4.10/lib/mysql2.rb:31:in require' /var/www/rails_api/shared/bundle/ruby/2.5.0/gems/mysql2-0.4.10/lib/mysql2.rb:31:in <top (required)>'
/home/tomoyoshi/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/bundler-1.16.1/lib/bundler/runtime.rb:81:in require' /home/tomoyoshi/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/bundler-1.16.1/lib/bundler/runtime.rb:81:in block (2 levels) in require'
/home/tomoyoshi/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/bundler-1.16.1/lib/bundler/runtime.rb:76:in each' /home/tomoyoshi/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/bundler-1.16.1/lib/bundler/runtime.rb:76:in block in require'
/home/tomoyoshi/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/bundler-1.16.1/lib/bundler/runtime.rb:65:in each' /home/tomoyoshi/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/bundler-1.16.1/lib/bundler/runtime.rb:65:in require'
/home/tomoyoshi/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/bundler-1.16.1/lib/bundler.rb:114:in require' /var/www/rails_api/releases/20180107005503/config/application.rb:17:in <top (required)>'
/var/www/rails_api/current/config/environment.rb:2:in require_relative' /var/www/rails_api/current/config/environment.rb:2:in <top (required)>'
/var/www/rails_api/current/config.ru:3:in require_relative' /var/www/rails_api/current/config.ru:3:in block in <main>'
/var/www/rails_api/shared/bundle/ruby/2.5.0/gems/rack-2.0.3/lib/rack/builder.rb:55:in instance_eval' /var/www/rails_api/shared/bundle/ruby/2.5.0/gems/rack-2.0.3/lib/rack/builder.rb:55:in initialize'
/var/www/rails_api/current/config.ru:in new' /var/www/rails_api/current/config.ru:in <main>'
/var/www/rails_api/shared/bundle/ruby/2.5.0/gems/rack-2.0.3/lib/rack/builder.rb:49:in eval' /var/www/rails_api/shared/bundle/ruby/2.5.0/gems/rack-2.0.3/lib/rack/builder.rb:49:in new_from_string'
/var/www/rails_api/shared/bundle/ruby/2.5.0/gems/rack-2.0.3/lib/rack/builder.rb:40:in parse_file' /var/www/rails_api/shared/bundle/ruby/2.5.0/gems/puma-3.11.0/lib/puma/configuration.rb:318:in load_rackup'
/var/www/rails_api/shared/bundle/ruby/2.5.0/gems/puma-3.11.0/lib/puma/configuration.rb:243:in app' /var/www/rails_api/shared/bundle/ruby/2.5.0/gems/puma-3.11.0/lib/puma/runner.rb:138:in load_and_bind'
/var/www/rails_api/shared/bundle/ruby/2.5.0/gems/puma-3.11.0/lib/puma/single.rb:87:in run' /var/www/rails_api/shared/bundle/ruby/2.5.0/gems/puma-3.11.0/lib/puma/launcher.rb:183:in run'
/var/www/rails_api/shared/bundle/ruby/2.5.0/gems/puma-3.11.0/lib/puma/cli.rb:77:in run' /var/www/rails_api/shared/bundle/ruby/2.5.0/gems/puma-3.11.0/bin/puma:10:in <top (required)>'
/var/www/rails_api/shared/bundle/ruby/2.5.0/bin/puma:23:in load' /var/www/rails_api/shared/bundle/ruby/2.5.0/bin/puma:23:in <top (required)>'

Answer 1

おそらく，puma の問題ではなく，mysql2 gem が正しくインストールできていない，という問題なので，そういう質問に変えたほうがよさそうです。

試しに

ruby -r mysql2 -e "puts Mysql2::VERSION"

とかやってみて，この gem が require できるかどうか確かめてみられては。

mysql2 のインストールはそれなりにハードルが高いです。

Comments

[TomM]

ご回答ありがとうございます。
実際にコマンドを打ってみました。ダメでしたので、mysql2のインストールなのでしょうね。。

/usr/share/rubygems/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- mysql2 (LoadError)
from /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:55:in `require'

[scivola]

同じ LoadError ですが，当初の質問のは mysql2.so が見つからない，というもので，今回試していただいたほうは gem 自体が見つけられていないようです。つまり現象としてはまったく違います。
同じ環境ですか？　gem list mysql2 では出てきますか？