$ ps -ef | grep unicorn
user    1797     1  0 Jul29 ?        00:00:06 unicorn master -c /var/www/user-cms/current/config/unicorn/production.rb -E deployment -D
user    1840  1797  8 Jul29 ?        02:42:10 unicorn worker[0] -c /var/www/user-cms/current/config/unicorn/production.rb -E deployment -D
user    1847  1797  8 Jul29 ?        02:40:24 unicorn worker[1] -c /var/www/user-cms/current/config/unicorn/production.rb -E deployment -D
user    1857  1797  8 Jul29 ?        02:40:50 unicorn worker[2] -c /var/www/user-cms/current/config/unicorn/production.rb -E deployment -D
user    1872  1797  8 Jul29 ?        02:38:32 unicorn worker[3] -c /var/www/user-cms/current/config/unicorn/production.rb -E deployment -D
user    1894  1797  8 Jul29 ?        02:39:10 unicorn worker[4] -c /var/www/user-cms/current/config/unicorn/production.rb -E deployment -D
user    1909  1797  7 Jul29 ?        02:37:28 unicorn worker[5] -c /var/www/user-cms/current/config/unicorn/production.rb -E deployment -D
21235    42323 42237  0 00:47 pts/3    00:00:00 grep unicorn

$ sudo su -
# ls -l /proc/1797/
合計 0
dr-xr-xr-x 2 user user 0  7月 31 00:47 2020 attr
-rw-r--r-- 1 user user 0  7月 31 00:47 2020 autogroup
-r-------- 1 user user 0  7月 31 00:47 2020 auxv
-r--r--r-- 1 user user 0  7月 31 00:47 2020 cgroup
--w------- 1 user user 0  7月 31 00:47 2020 clear_refs
-r--r--r-- 1 user user 0  7月 31 00:46 2020 cmdline
-rw-r--r-- 1 user user 0  7月 31 00:47 2020 comm
-rw-r--r-- 1 user user 0  7月 31 00:47 2020 coredump_filter
-r--r--r-- 1 user user 0  7月 31 00:47 2020 cpuset
lrwxrwxrwx 1 user user 0  7月 31 00:47 2020 cwd -> /var/www/user-cms/releases/20200729065345
-r-------- 1 user user 0  7月 31 00:47 2020 environ
lrwxrwxrwx 1 user user 0  7月 31 00:47 2020 exe -> /usr/local/rbenv/versions/2.4.10/bin/ruby
dr-x------ 2 user user 0  7月 31 00:47 2020 fd
dr-x------ 2 user user 0  7月 31 00:47 2020 fdinfo
-r-------- 1 user user 0  7月 31 00:47 2020 io
-rw------- 1 user user 0  7月 31 00:47 2020 limits
-rw-r--r-- 1 user user 0  7月 31 00:47 2020 loginuid
-r--r--r-- 1 user user 0  7月 31 00:47 2020 maps
-rw------- 1 user user 0  7月 31 00:47 2020 mem
-r--r--r-- 1 user user 0  7月 31 00:47 2020 mountinfo
-r--r--r-- 1 user user 0  7月 31 00:47 2020 mounts
-r-------- 1 user user 0  7月 31 00:47 2020 mountstats
dr-xr-xr-x 6 user user 0  7月 31 00:47 2020 net
dr-x--x--x 2 user user 0  7月 31 00:47 2020 ns
-r--r--r-- 1 user user 0  7月 31 00:47 2020 numa_maps
-rw-r--r-- 1 user user 0  7月 31 00:47 2020 oom_adj
-r--r--r-- 1 user user 0  7月 31 00:47 2020 oom_score
-rw-r--r-- 1 user user 0  7月 31 00:47 2020 oom_score_adj
-r--r--r-- 1 user user 0  7月 31 00:47 2020 pagemap
-r--r--r-- 1 user user 0  7月 31 00:47 2020 personality
lrwxrwxrwx 1 user user 0  7月 31 00:47 2020 root -> /
-rw-r--r-- 1 user user 0  7月 31 00:47 2020 sched
-r--r--r-- 1 user user 0  7月 31 00:47 2020 schedstat
-r--r--r-- 1 user user 0  7月 31 00:47 2020 sessionid
-r--r--r-- 1 user user 0  7月 31 00:47 2020 smaps
-r--r--r-- 1 user user 0  7月 31 00:47 2020 stack
-r--r--r-- 1 user user 0  7月 31 00:46 2020 stat
-r--r--r-- 1 user user 0  7月 31 00:47 2020 statm
-r--r--r-- 1 user user 0  7月 30 22:38 2020 status
-r--r--r-- 1 user user 0  7月 31 00:47 2020 syscall
dr-xr-xr-x 5 user user 0  7月 31 00:47 2020 task
-r--r--r-- 1 user user 0  7月 31 00:47 2020 wchan

$ bundle exec cap production deploy:stop
$ bundle exec cap production deploy:start
（productionは環境名）

$ docker logs コンテナID
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: error: /etc/nginx/conf.d/default.conf is not a file or does not exist
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.sh: Configuration complete; ready for start up
2020/07/22 07:55:16 [emerg] 1#1: host not found in upstream "rails:3000" in /etc/nginx/conf.d/rails.conf:2
nginx: [emerg] host not found in upstream "rails:3000" in /etc/nginx/conf.d/rails.conf:2

Ignoring (gem名) because its extensions are not built.

$ docker volume ls
DRIVER              VOLUME NAME
local               0d506af3b9c55280acce2e034fb7ff2b6f19c9c23192e6de91ac406702236f8d
local               2f6589f1ec9c16dd1fcdc638aa2df316c3d1e5fa9c712651e8b61997ca26d0d1
local               3c8d4c4aa95221be36b5adc472549440e7330764ad3b8bef08f37d4d59f4d4ba
...

$ docker volume ls -f dangling=true
DRIVER              VOLUME NAME
local               0d506af3b9c55280acce2e034fb7ff2b6f19c9c23192e6de91ac406702236f8d
local               2f6589f1ec9c16dd1fcdc638aa2df316c3d1e5fa9c712651e8b61997ca26d0d1
local               3c8d4c4aa95221be36b5adc472549440e7330764ad3b8bef08f37d4d59f4d4ba
...

$ docker volume ls -qf dangling=true | xargs docker volume rm
2f6589f1ec9c16dd1fcdc638aa2df316c3d1e5fa9c712651e8b61997ca26d0d1
3c8d4c4aa95221be36b5adc472549440e7330764ad3b8bef08f37d4d59f4d4ba
5cb87cee19c530d3dc8e903a93501333ebdb7b191a220a24c6eec4b8cc1151f7
...

$ docker volume inspect web_bundle
[
    {
        "CreatedAt": "2020-07-16T13:09:21Z",
        "Driver": "local",
        "Labels": {
            "com.docker.compose.project": "web",
            "com.docker.compose.version": "1.25.4",
            "com.docker.compose.volume": "bundle"
        },
        "Mountpoint": "/var/lib/docker/volumes/web_bundle/_data",
        "Name": "web_bundle",
        "Options": null,
        "Scope": "local"
    }
]

$ ls -l /var/lib/docker/volumes/web_bundle/_data
ls: /var/lib/docker/volumes/web_bundle/_data: No such file or directory

$ screen ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/tty

docker-desktop:~# __  __

Welcome to LinuxKit

                        ##         .
                  ## ## ##        ==
               ## ## ## ## ##    ===
           /"""""""""""""""""__/ ===
          {                       /  ===-
           _____ O           __/
                        __/
              _________/

docker-desktop login: root (automatic login)

Welcome to LinuxKit!

NOTE: This system is namespaced.
The namespace you are currently in may not be the root.
System services are namespaced; to access, use `ctr -n services.linuxkit ...`
login[72826]: root login on 'ttyS0'

docker-desktop:~# ls -l /var/lib/docker/volumes/web_bundle/_data
total 84
drwxr-xr-x    2 root     root          4096 Jul 16 13:09 bin
drwxr-xr-x    2 root     root          4096 Apr  3 15:49 build_info
drwxr-xr-x    3 root     root          4096 Apr  3 15:49 bundler
drwxr-xr-x    3 root     root         20480 Jul 16 11:59 cache
-rw-r--r--    1 root     root            60 Jul 16 13:09 config
drwxr-xr-x    4 root     root          4096 Jul 14 02:21 doc
drwxr-xr-x    3 root     root          4096 Apr  3 15:50 extensions
drwxr-xr-x  264 root     root         16384 Jul 16 11:59 gems
drwxr-xr-x    4 root     root          4096 Jul 14 01:47 ruby
drwxr-xr-x    2 root     root         20480 Jul 16 11:59 specifications

on:
  push:
    branches: [ master ]
  pull_request:
    branches: [ master ]

jobs:
  test:
    runs-on: ubuntu-latest

- uses: actions/checkout@v2
- name: Set up Ruby
  uses: ruby/setup-ruby@ec106b438a1ff6ff109590de34ddc62c540232e0
  with:
    ruby-version: 2.7.1
- name: Install dependencies
  run: bundle install

services:
  mysql:
    image: mysql:5.6
    ports:
      - 3306:3306
    env:
      MYSQL_ROOT_PASSWORD: root

test:
  adapter: mysql2
  encoding: utf8
  collation: utf8_general_ci
  username: root
  password: root
  host: localhost
  database: github_actions_for_rails_test
  reconnect: false

- name: Setup Database
  env:
    RAILS_ENV: test
  run: |
    cp config/database.yml.ci config/database.yml
    ./bin/rails db:create
    ./bin/rails db:migrate

Mysql2::Error::ConnectionError: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

- name: Setup Database
  env:
    RAILS_ENV: test
  run: |
    sudo systemctl start mysql
    cp config/database.yml.ci config/database.yml
    ./bin/rails db:create
    ./bin/rails db:migrate

test:
  adapter: mysql2
  encoding: utf8
  collation: utf8_general_ci
  username: root
  password: root
  host: 127.0.0.1
  database: github_actions_for_rails_test
  reconnect: false

# This workflow uses actions that are not certified by GitHub.
# They are provided by a third-party and are governed by
# separate terms of service, privacy policy, and support
# documentation.
# This workflow will download a prebuilt Ruby version, install dependencies and run tests with Rake
# For more information see: https://github.com/marketplace/actions/setup-ruby-jruby-and-truffleruby

name: Ruby

on:
  push:
    branches: [ master ]
  pull_request:
    branches: [ master ]

jobs:
  test:

    runs-on: ubuntu-latest
    services:
      mysql:
        image: mysql:5.6
        ports:
          - 3306:3306
        env:
          MYSQL_ROOT_PASSWORD: root

    steps:
    - uses: actions/checkout@v2
    - name: Set up Ruby
    # To automatically get bug fixes and new Ruby versions for ruby/setup-ruby,
    # change this to (see https://github.com/ruby/setup-ruby#versioning):
    # uses: ruby/setup-ruby@v1
      uses: ruby/setup-ruby@ec106b438a1ff6ff109590de34ddc62c540232e0
      with:
        ruby-version: 2.7.1

    - name: Setup Database
      env:
        RAILS_ENV: test
      run: |
        cp config/database.yml.ci config/database.yml
        ./bin/rails db:create
        ./bin/rails db:migrate
    - name: Run tests
      run: ./bin/rails test

$ anyenv update
Updating 'anyenv'...
Updating 'anyenv/anyenv-update'...
Updating 'ndenv'...
Updating 'ndenv/ndenv-yarn-install'...
Updating 'ndenv/node-build'...
Updating 'rbenv'...
 |  From https://github.com/rbenv/rbenv
 |  c2cfbd1..c879cb0  master     -> origin/master
Updating 'rbenv/ruby-build'...
 |  From https://github.com/rbenv/ruby-build
 |  637ddf3..69ccbf4  master     -> origin/master
 |  * [new tag]         v20200518  -> v20200518
 |  * [new tag]         v20200519  -> v20200519
 |  * [new tag]         v20200520  -> v20200520

$ rbenv install -l
2.5.8
2.6.6
2.7.1
jruby-9.2.12.0
maglev-1.0.0
mruby-2.1.1
rbx-5.0
truffleruby-20.1.0

Only latest stable releases for each Ruby implementation are shown.
Use 'rbenv install --list-all' to show all local versions.

$ rbenv install 2.7.1
Downloading openssl-1.1.1g.tar.gz...
-> https://dqw8nmjcqpjn7.cloudfront.net/ddb04774f1e32f0c49751e21b67216ac87852ceb056b75209af2443400636d46
Installing openssl-1.1.1g...
Installed openssl-1.1.1g to /Users/username/.anyenv/envs/rbenv/versions/2.7.1

Downloading ruby-2.7.1.tar.bz2...
-> https://cache.ruby-lang.org/pub/ruby/2.7/ruby-2.7.1.tar.bz2
Installing ruby-2.7.1...
ruby-build: using readline from homebrew
Installed ruby-2.7.1 to /Users/username/.anyenv/envs/rbenv/versions/2.7.1

$ rbenv local 2.7.1
$ ruby -v
ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x86_64-darwin19]

$ bundler init
Writing new Gemfile to ~/github/github_actions_for_rails/Gemfile

gem 'rails'
gem 'mysql2'

Installing mysql2 0.5.3 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

（中略）

linking shared-object mysql2/mysql2.bundle
ld: library not found for -lssl
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [mysql2.bundle] Error 1

make failed, exit code 2

$ bundle config --local build.mysql2 "--with-ldflags=-L/usr/local/opt/openssl/lib"

$ bundle exec rails new . -d mysql

rails  webpacker:install
Webpacker requires Node.js >= 8.16.0 and you are using 8.9.4
Please upgrade Node.js https://nodejs.org/en/download/

$ ndenv install v12.18.2
Downloading node-v12.18.2-darwin-x64.tar.gz...
-> https://nodejs.org/dist/v12.18.2/node-v12.18.2-darwin-x64.tar.gz
Installing node-v12.18.2-darwin-x64...
Installed node-v12.18.2-darwin-x64 to /Users/username/.anyenv/envs/ndenv/versions/v12.18.2

Installing Yarn...
/Users/username/.anyenv/envs/ndenv/versions/v12.18.2/bin/yarn -> /Users/username/.anyenv/envs/ndenv/versions/v12.18.2/lib/node_modules/yarn/bin/yarn.js
/Users/username/.anyenv/envs/ndenv/versions/v12.18.2/bin/yarnpkg -> /Users/username/.anyenv/envs/ndenv/versions/v12.18.2/lib/node_modules/yarn/bin/yarn.js
+ yarn@1.22.4
added 1 package in 0.82s
Installed Yarn 1.22.4
$ ndenv local v12.18.2
$ node -v
v12.18.2

$ rails webpacker:install
create  config/webpacker.yml
Copying webpack core config
create  config/webpack

（中略）

Webpacker successfully installed 🎉 🍰

$ ./bin/rails s -b 0.0.0.0
=> Booting Puma
=> Rails 6.0.3.2 application starting in development
=> Run `rails server --help` for more startup options
Puma starting in single mode...
* Version 4.3.5 (ruby 2.7.1-p83), codename: Mysterious Traveller
* Min threads: 5, max threads: 5
* Environment: development
* Listening on tcp://0.0.0.0:3000
Use Ctrl-C to stop

on:
  push:
    branches: [ master ]
  pull_request:
    branches: [ master ]

$ docker container inspect mw0001 --format={{'.NetworkSettings.IPAddress'}}
172.17.0.4

$ docker container inspect mw0001
[
    {
        "Id": "a4d1693a7981100b015d75f958468069c7418e11dad13e042bf26f5454246581",
        "Created": "2020-06-22T11:03:55.9929367Z",
        "Path": "/sbin/init",
        "Args": [],
        "State": {
            "Status": "running",
            "Running": true,
            "Paused": false,
            "Restarting": false,
            "OOMKilled": false,
            ...
（中略）
            ...
            "MacAddress": "02:42:ac:11:00:04",
            "Networks": {
                "bridge": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": null,
                    "NetworkID": "d6a62553445bbae6f040e8972635b12995ca2b23f0328ab8736f7a2b71d541bb",
                    "EndpointID": "73fae0f570728362bbe4c504ef79e98df191c9352375e9d1805b73ef56613ad2",
                    "Gateway": "172.17.0.1",
                    "IPAddress": "172.17.0.4",
                    "IPPrefixLen": 16,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:11:00:04",
                    "DriverOpts": null
                }
            }
        }
    }
]

$ docker stop mw0001
$ docker rm mw0001
$ docker container run -itd --tmpfs /tmp --tmpfs /run --mount type=bind,src=/sys/fs/cgroup,dst=/sys/fs/cgroup,readonly --stop-signal SIGRTMIN+3 -v /var/www/html --name mw0001 -h mw0001 --link mariadb0001:db0001 -p 8080:80 centos:mw0001 /sbin/init

Cannot access the database: MySQL server has gone away (172.17.0.3)。
以下のホスト名、ユーザー名、パスワードを確認してから再度試してください。

$ docker container ls
CONTAINER ID        IMAGE                        COMMAND                  CREATED             STATUS              PORTS                       NAMES
65b5af36d7ac        centos:mariadb0001           "/mariadb.sh"            4 days ago          Up 4 days           3306/tcp                    mariadb0001

$ docker run -d -e DBNAME=testdb -e MARIADBUSER=root -e MARIADBPASSWORD=mysqlPassword -v /var/lib/mysql:/var/lib/mysql:rw --name mariadb0001 centos:mariadb0001

$ ls /var/lib/mysql
65b5af36d7ac.pid	ib_logfile1		mysql.sock
aria_log.00000001	ibdata1			performance_schema
aria_log_control	ibtmp1			test
ib_buffer_pool		multi-master.info
ib_logfile0		mysql

FROM centos:7.5.1804
RUN yum remove -y php* && \
    yum install -y http://rpms.famillecollet.com/enterprise/remi-release-7.rpm && \
    yum install -y --enablerepo=remi,remi-php72 php php-mysqlnd php-mbstring php-xml httpd openssh-clients && \
    curl -O https://releases.wikimedia.org/mediawiki/1.31/mediawiki-1.31.0.tar.gz && \
    tar xzvf /mediawiki-1.31.0.tar.gz -C /var/www/html/

WORKDIR /var/www/html
RUN ln -sf ./mediawiki-1.31.0 wiki && systemctl enable httpd

$ docker image build -f Dockerfile -t centos:mw0001 .
Sending build context to Docker daemon  2.048kB
Step 1/4 : FROM centos:7.5.1804
 ---> cf49811e3cdb
Step 2/4 : RUN yum remove -y php* &&     yum install -y http://rpms.famillecollet.com/enterprise/remi-release-7.rpm &&     yum install -y --enablerepo=remi,remi-php72 php php-mysqlnd php-mbstring php-xml httpd openssh-clients &&     curl -O https://releases.wikimedia.org/mediawiki/1.31/mediawiki-1.31.0.tar.gz &&     tar xzvf /mediawiki-1.31.0.tar.gz -C /var/www/html/
 ---> Running in c808fb96ff1d

 （中略）

Removing intermediate container c808fb96ff1d
 ---> 90815ed52b36
Step 3/4 : WORKDIR /var/www/html
 ---> Running in 5b4fdf6b5b97
Removing intermediate container 5b4fdf6b5b97
 ---> e535a272bbf0
Step 4/4 : RUN ln -sf ./mediawiki-1.31.0 wiki && systemctl enable httpd
 ---> Running in 9733db996f6f
Created symlink /etc/systemd/system/multi-user.target.wants/httpd.service, pointing to /usr/lib/systemd/system/httpd.service.
Removing intermediate container 9733db996f6f
 ---> 67b7fb3ff7d6
Successfully built 67b7fb3ff7d6
Successfully tagged centos:mw0001

$ docker container run -itd --tmpfs /tmp --tmpfs /run --mount type=bind,src=/sys/fs/cgroup,dst=/sys/fs/cgroup,readonly --stop-signal SIGRTMIN+3 -v /var/www/html --name mw0001 -h mw0001 --link mariadb0001:db0001 centos:mw0001 /sbin/init

$ docker container ls
CONTAINER ID        IMAGE                        COMMAND                  CREATED             STATUS              PORTS                       NAMES
a4d1693a7981        centos:mw0001                "/sbin/init"             3 hours ago         Up 3 hours                                      mw0001
65b5af36d7ac        centos:mariadb0001           "/mariadb.sh"            4 days ago          Up 4 days           3306/tcp                    mariadb0001

$ docker container exec -it mw0001 env
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=mw0001
TERM=xterm
DB0001_PORT=tcp://172.17.0.3:3306
DB0001_PORT_3306_TCP=tcp://172.17.0.3:3306
DB0001_PORT_3306_TCP_ADDR=172.17.0.3
DB0001_PORT_3306_TCP_PORT=3306
DB0001_PORT_3306_TCP_PROTO=tcp
DB0001_NAME=/mw0001/db0001
DB0001_ENV_MARIADBUSER=root
DB0001_ENV_MARIADBPASSWORD=mysqlPassword
DB0001_ENV_DBNAME=testdb
HOME=/root

$ docker container exec -it mw0001 cat /etc/hosts
127.0.0.1	localhost
::1	localhost ip6-localhost ip6-loopback
fe00::0	ip6-localnet
ff00::0	ip6-mcastprefix
ff02::1	ip6-allnodes
ff02::2	ip6-allrouters
172.17.0.3	db0001 65b5af36d7ac mariadb0001
172.17.0.4	mw0001