Flyway通过Docker连接PostgreSQL失败问题求助

问题回顾 #

第一阶段：数据库类型无法识别 #

执行以下Flyway命令时出现错误：

$ docker run --rm -v /var/lib/jenkins/workspace/flyway@2/jenkins_flyway/sql:/flyway/sql -v /var/lib/jenkins/workspace/flyway@2/jenkins_flyway/conf:/flyway/conf flyway/flyway:10.13.0 -user=postgres -password=postgres migrate

错误输出：

WARNING: Storing migrations in 'sql' is not recommended and default scanning of this location may be deprecated in a future release
ERROR: No database found to handle "jdbc:postgresql://localhost:5432/mydb"

原因：Flyway配置文件中属性值使用了引号（比如flyway.url="jdbc:postgresql://localhost:5432/mydb"），去掉引号即可解决该错误。

第二阶段：连接被拒绝 #

修正配置后执行命令：

docker run --rm -v /var/lib/jenkins/workspace/flyway/jenkins_flyway/sql:/flyway/sql -v /var/lib/jenkins/workspace/flyway/jenkins_flyway/conf:/flyway/conf flyway/flyway:8.5.1 migrate

错误输出：

ERROR: Unable to obtain connection from database (jdbc:postgresql://localhost:5432/flyway) for user 'postgres': Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections. #

SQL State : 08001
Error Code : 0
Message : Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.

Caused by: org.postgresql.util.PSQLException: Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
Caused by: java.net.ConnectException: Connection refused (Connection refused)

核心原因：Docker容器内的localhost指向容器自身，而非宿主机上的PostgreSQL服务，导致连接失败。

解决方案 #

1. 使用宿主机Docker网桥IP替代localhost #

• 查看宿主机Docker网桥的IP（Linux系统执行ip addr show docker0，通常为172.17.0.1）
• 修改Flyway配置中的JDBC URL为jdbc:postgresql://172.17.0.1:5432/flyway，重新执行命令

2. 使用Docker host网络模式 #

运行Flyway容器时添加--network host参数，让容器共享宿主机网络栈，此时localhost将指向宿主机：

docker run --rm --network host -v /var/lib/jenkins/workspace/flyway/jenkins_flyway/sql:/flyway/sql -v /var/lib/jenkins/workspace/flyway/jenkins_flyway/conf:/flyway/conf flyway/flyway:8.5.1 migrate

3. 若PostgreSQL为Docker容器，使用容器名作为主机名 #

• 确保PostgreSQL容器与Flyway容器处于同一Docker网络（若未创建网络，执行docker network create flyway-net，启动PostgreSQL时添加--network flyway-net）
• 修改JDBC URL为jdbc:postgresql://postgres-container:5432/flyway（替换postgres-container为你的PostgreSQL容器名称）

额外检查项 #

• 确认PostgreSQL配置文件postgresql.conf中listen_addresses = '*'，允许所有IP访问
• 修改pg_hba.conf添加规则允许Docker网络连接：host all all 172.17.0.0/16 md5
• 确认宿主机防火墙未拦截5432端口

内容的提问来源于stack exchange，提问作者Gaurav Matta