我正在为我的示例应用程序运行docker-compose，并且此文件包含mysql数据库和应用程序映像。我收到以下错误。
$ docker logs -f sample-application
Can't connect to MySQL server on 'mysql' (111 "Connection refused")
Couldn't create database for {"adapter"=>"mysql2", "encoding"=>"utf8", "pool"=>5, "reconnect"=>true, "database"=>"datagen", "username"=>"root", "password"=>"password", "host"=>"mysql", "port"=>3306}
rake aborted!
Mysql2::Error::ConnectionError: Can't connect to MySQL server on 'mysql' (111 "Connection refused")
/usr/local/bundle/gems/mysql2-0.5.2/lib/mysql2/client.rb:90:in `connect'
/usr/local/bundle/gems/mysql2-0.5.2/lib/mysql2/client.rb:90:in `initialize'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/connection_adapters/mysql2_adapter.rb:22:in `new'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/connection_adapters/mysql2_adapter.rb:22:in `mysql2_connection'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:809:in `new_connection'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:853:in `checkout_new_connection'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:832:in `try_to_checkout_new_connection'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:793:in `acquire_connection'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:521:in `checkout'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:380:in `connection'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:1008:in `retrieve_connection'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/connection_handling.rb:118:in `retrieve_connection'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/connection_handling.rb:90:in `connection'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/tasks/mysql_database_tasks.rb:6:in `connection'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/tasks/mysql_database_tasks.rb:14:in `create'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/tasks/database_tasks.rb:119:in `create'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/tasks/database_tasks.rb:139:in `block in create_current'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/tasks/database_tasks.rb:316:in `block in each_current_configuration'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/tasks/database_tasks.rb:313:in `each'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/tasks/database_tasks.rb:313:in `each_current_configuration'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/tasks/database_tasks.rb:138:in `create_current'
/usr/local/bundle/gems/activerecord-5.2.1/lib/active_record/railties/databases.rake:29:in `block (2 levels) in <top (required)>'
/usr/local/bundle/gems/rake-12.3.1/exe/rake:27:in `<top (required)>'
Tasks: TOP => db:create
(See full trace by running task with --trace)
这是mysql docker-compose yaml文件的数据库组件
version: '3.1'
services:
sample-service:
image: service:latest
hostname: sample-service
container_name: sample-service
depends_on:
- sample-application
ports:
- "8080:8080"
networks:
- $NETWORK_NAME
mysql:
image: mysql:5.7
hostname: mysql
container_name: mysql
ports:
- "3306:3306"
environment:
- MYSQL_ROOT_PASSWORD=password
- MYSQL_DATABASE=foo
- MYSQL_USER=root
- MYSQL_PASSWORD=password
networks:
- $NETWORK_NAME
sample-application:
image: sample:latest
hostname: mysql
container_name: sample-application
depends_on:
- mysql
ports:
- "3000:3000"
environment:
- RAILS_ENV=production
- DATABASE_HOST=mysql
- DATABASE_USER=root
- DATABASE_NAME=foo
- DATABASE_PORT=3306
networks:
- $NETWORK_NAME
networks:
datagen:
external: true
我能够从应用程序docker容器映像ping mysql。连接成功，同时我还可以从其他计算机访问mysql映像。
因此，在mysql映像中没有问题，但是使用docker compose运行时我无法连接到mysql主机。我通过的环境变量也是正确的。
我研究了stackoverflow中的各种问题，并试图更改绑定地址。但我在我的mysql容器映像中看不到它。
bash-4.2# find / -name "*.cnf"
/var/lib/mysql/auto.cnf
/usr/share/mysql/my-default.cnf
/etc/pki/tls/openssl.cnf
/etc/my.cnf
/healthcheck.cnf
bash-4.2# cat /etc/my.cnf
# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.6/en/server-configuration-defaults.html
[mysqld]
#
# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M
#
# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
# log_bin
#
# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M
skip-host-cache
skip-name-resolve
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
secure-file-priv=/var/lib/mysql-files
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
答案 0 :(得分：1)
您真的需要外部网络吗？唯一可能的原因是您想将其他容器连接到它。否则，请不要使用它-您将可以通过端口公开机制从主机访问容器。
如果您不打算从docker-compose外部访问数据库，请考虑对文件进行以下更改：
docker-compose.yml
version: '3.1'
services:
mysql:
image: mysql:5.7
environment:
- MYSQL_ROOT_PASSWORD=password
- MYSQL_DATABASE=foo
- MYSQL_USER=root
- MYSQL_PASSWORD=password
sample-application:
image: sample:latest
depends_on:
- mysql
environment:
- RAILS_ENV=production
- DATABASE_HOST=mysql
- DATABASE_USER=root
- DATABASE_NAME=foo
- DATABASE_PORT=3306
sample-service:
image: service:latest
depends_on:
- sample-application
通过这种配置，您可以按名称访问网络内部的服务，例如mysql，sample-service和sample-application
服务取决于应用程序而不是反之时的奇怪情况
答案 1 :(得分：0)
如果使用Rails连接到Mysql，请确保database.yml中的数据库主机与mysql中的服务名称（在本例中为docker-compose）相同，知道如何连接到mysql容器。删除所有容器和映像并从头开始进行构建，以确保未缓存任何配置。