最新Liquibase Docker镜像连接MySQL报通信链路失败错误

问题场景 #

正在开展POC验证工作，尝试通过Liquibase官方Docker镜像连接MySQL实例发布数据库变更，操作参考了Liquibase官方Docker使用文档、官方Docker镜像说明、公开示例项目，测试覆盖MySQL 5.7、MySQL 8.x两个主流版本，均复现相同连接错误。

报错详情 #

Connection could not be created to jdbc:mysql://localhost:3306/denmark with driver 
com.mysql.cj.jdbc.Driver.  Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has 
not received any packets from the server.
liquibase.exception.CommandExecutionException: liquibase.exception.LiquibaseException: 
Unexpected error running Liquibase: liquibase.exception.DatabaseException: liquibase.exception.DatabaseException: Connection could not be created to 
jdbc:mysql://localhost:3306/denmark with driver com.mysql.cj.jdbc.Driver.  
Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has 
not received any packets from the server.
    at liquibase.command.CommandScope.execute(CommandScope.java:163)
    at liquibase.integration.commandline.CommandRunner.call(CommandRunner.java:51)
    at liquibase.integration.commandline.CommandRunner.call(CommandRunner.java:21)
    at picocli.CommandLine.executeUserObject(CommandLine.java:1953)
    at picocli.CommandLine.access$1300(CommandLine.java:145)
    at picocli.CommandLine$RunLast.executeUserObjectOfLastSubcommandWithSameParent(CommandLine.java:2358)
    at picocli.CommandLine$RunLast.handle(CommandLine.java:2352)
    at picocli.CommandLine$RunLast.handle(CommandLine.java:2314)
    at picocli.CommandLine$AbstractParseResultHandler.execute(CommandLine.java:2179)
    at picocli.CommandLine$RunLast.execute(CommandLine.java:2316)
    at picocli.CommandLine.execute(CommandLine.java:2078)
    at liquibase.integration.commandline.LiquibaseCommandLine.lambda$execute$1(LiquibaseCommandLine.java:336)
    at liquibase.Scope.child(Scope.java:189)
    at liquibase.Scope.child(Scope.java:165)
    at liquibase.integration.commandline.LiquibaseCommandLine.execute(LiquibaseCommandLine.java:301)
    at liquibase.integration.commandline.LiquibaseCommandLine.main(LiquibaseCommandLine.java:90)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.base/java.lang.reflect.Method.invoke(Unknown Source)
    at liquibase.integration.commandline.LiquibaseLauncher.main(LiquibaseLauncher.java:91)

排查与解决步骤 #

按优先级从高到低逐一验证：

• 修正JDBC连接地址（90%以上同类问题根因）
  当前JDBC地址里写的localhost是错误指向：Docker容器内的localhost是Liquibase容器自身的回环地址，不是宿主机/MySQL所在服务的地址，根据MySQL部署场景替换主机地址：
  • 如果MySQL部署在Docker宿主机上：
    • Linux环境：将localhost替换为172.17.0.1（Docker默认网桥的宿主机网关IP），或启动Liquibase容器时添加--network=host参数直接共享宿主机网络栈
    • Mac/Windows（Docker Desktop环境）：将localhost替换为host.docker.internal，该域名是Docker Desktop内置的宿主机解析地址
  • 如果MySQL同样运行在Docker容器中：提前创建自定义Docker网络，将Liquibase容器和MySQL容器都加入该网络，JDBC地址中直接写MySQL容器的服务名/容器名作为主机地址，不要用IP或localhost
• 验证MySQL访问权限与监听配置
  • 检查MySQL配置文件中的bind-address参数，不要绑定127.0.0.1，需配置为0.0.0.0或对应服务网卡IP，否则外部请求无法到达MySQL
  • 检查连接使用的数据库账号权限，确保账号允许从Liquibase所在IP段登录，不要仅限定localhost本地登录，可执行如下SQL授权：

    GRANT ALL PRIVILEGES ON denmark.* TO '你的连接用户名'@'%' IDENTIFIED BY '你的连接密码';
    FLUSH PRIVILEGES;
    

  • 连通性校验：先在宿主机通过mysql -h <你配置的连接IP> -P 3306 -u 用户名 -p验证端口和账号可用，再进入Liquibase容器内部通过telnet、nc等工具验证到MySQL 3306端口的网络连通性
• 补全JDBC连接必要参数
  部分MySQL 8.x版本会因为SSL、公钥检索、时区配置问题导致连接失败，可将JDBC URL调整为如下格式重试：

  jdbc:mysql://<正确的主机地址>:3306/denmark?useSSL=false&allowPublicKeyRetrieval=true&serverTimezone=UTC
  

• 检查网络规则
  确认宿主机、云服务器安全组、本地防火墙规则已放通3306端口的入站请求，且3306端口确实由MySQL服务监听，未被其他进程占用。

内容的提问来源于stack exchange，提问作者Vibhu Banga