My Spring app running on Docker for Windows crashes due to an UnknownHostException - spring

Question

I'm trying to run a Spring app in a Docker container, but it keeps crashing due to an UnknownHostException caused by an image named "some-postgres". I had downloaded the official Postgres Docker image at https://hub.docker.com/_/postgres, and followed the setup instructions, and I created an image called "some-postgres". At some point, I set spring.datasource.url in my applications.properties to jdbc:postgresql://some-postgres:5432/docker_atm, and now, no matter what I use as my data source URL, and regardless of whether there's any usages of "some-postgres" in my project, I keep getting this error stacktrace:
2022-10-04T10:56:32.114821300Z at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:331) ~[postgresql-42.5.0.jar!/:42.5.0]
2022-10-04T10:56:32.114843600Z at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49) ~[postgresql-42.5.0.jar!/:42.5.0]
2022-10-04T10:56:32.114847500Z at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:247) ~[postgresql-42.5.0.jar!/:42.5.0]
2022-10-04T10:56:32.114850500Z at org.postgresql.Driver.makeConnection(Driver.java:434) ~[postgresql-42.5.0.jar!/:42.5.0]
2022-10-04T10:56:32.114853100Z at org.postgresql.Driver.connect(Driver.java:291) ~[postgresql-42.5.0.jar!/:42.5.0]
2022-10-04T10:56:32.114855800Z at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) ~[HikariCP-4.0.3.jar!/:na]
2022-10-04T10:56:32.114858400Z at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:364) ~[HikariCP-4.0.3.jar!/:na]
2022-10-04T10:56:32.114861100Z at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206) ~[HikariCP-4.0.3.jar!/:na]
2022-10-04T10:56:32.114863800Z at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:476) [HikariCP-4.0.3.jar!/:na]
2022-10-04T10:56:32.114866500Z at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:561) [HikariCP-4.0.3.jar!/:na]
2022-10-04T10:56:32.114869200Z at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) [HikariCP-4.0.3.jar!/:na]
2022-10-04T10:56:32.114871900Z at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) [HikariCP-4.0.3.jar!/:na]
2022-10-04T10:56:32.114874600Z at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122) [hibernate-core-5.6.11.Final.jar!/:5.6.11.Final]
2022-10-04T10:56:32.114877400Z at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess.obtainConnection(JdbcEnvironmentInitiator.java:181) [hibernate-core-5.6.11.Final.jar!/:5.6.11.Final]
2022-10-04T10:56:32.114884400Z at org.hibernate.resource.transaction.backend.jdbc.internal.DdlTransactionIsolatorNonJtaImpl.getIsolatedConnection(DdlTransactionIsolatorNonJtaImpl.java:44) [hibernate-core-5.6.11.Final.jar!/:5.6.11.Final]
2022-10-04T10:56:32.114887400Z at org.hibernate.tool.schema.internal.exec.ImprovedExtractionContextImpl.getJdbcConnection(ImprovedExtractionContextImpl.java:63) [hibernate-core-5.6.11.Final.jar!/:5.6.11.Final]
2022-10-04T10:56:32.114890300Z at org.hibernate.tool.schema.extract.spi.ExtractionContext.getQueryResults(ExtractionContext.java:43) [hibernate-core-5.6.11.Final.jar!/:5.6.11.Final]
2022-10-04T10:56:32.114893000Z at org.hibernate.tool.schema.extract.internal.SequenceInformationExtractorLegacyImpl.extractMetadata(SequenceInformationExtractorLegacyImpl.java:39) [hibernate-core-5.6.11.Final.jar!/:5.6.11.Final]
2022-10-04T10:56:32.114896100Z at org.hibernate.tool.schema.extract.internal.DatabaseInformationImpl.initializeSequences(DatabaseInformationImpl.java:66) [hibernate-core-5.6.11.Final.jar!/:5.6.11.Final]
2022-10-04T10:56:32.114898900Z at org.hibernate.tool.schema.extract.internal.DatabaseInformationImpl.<init>(DatabaseInformationImpl.java:60) [hibernate-core-5.6.11.Final.jar!/:5.6.11.Final]
2022-10-04T10:56:32.114904900Z at org.hibernate.tool.schema.internal.Helper.buildDatabaseInformation(Helper.java:183) [hibernate-core-5.6.11.Final.jar!/:5.6.11.Final]
2022-10-04T10:56:32.114908000Z at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.doMigration(AbstractSchemaMigrator.java:104) [hibernate-core-5.6.11.Final.jar!/:5.6.11.Final]
2022-10-04T10:56:32.114911100Z at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:196) [hibernate-core-5.6.11.Final.jar!/:5.6.11.Final]
2022-10-04T10:56:32.114915000Z at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:85) [hibernate-core-5.6.11.Final.jar!/:5.6.11.Final]
2022-10-04T10:56:32.114919000Z at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:335) [hibernate-core-5.6.11.Final.jar!/:5.6.11.Final]
2022-10-04T10:56:32.114922700Z at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:471) [hibernate-core-5.6.11.Final.jar!/:5.6.11.Final]
2022-10-04T10:56:32.114927000Z at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1498) [hibernate-core-5.6.11.Final.jar!/:5.6.11.Final]
2022-10-04T10:56:32.114931700Z at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:58) [spring-orm-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114936200Z at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) [spring-orm-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114940600Z at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:409) [spring-orm-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114944800Z at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:396) [spring-orm-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114949200Z at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) [spring-orm-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114953900Z at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1863) [spring-beans-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114958200Z at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1800) [spring-beans-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114962100Z at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:620) [spring-beans-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114965500Z at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) [spring-beans-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114968300Z at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) [spring-beans-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114975000Z at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114978400Z at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) [spring-beans-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114982400Z at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) [spring-beans-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114985200Z at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1154) ~[spring-context-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114988100Z at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:908) ~[spring-context-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114991100Z at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.23.jar!/:5.3.23]
2022-10-04T10:56:32.114993800Z at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:147) ~[spring-boot-2.7.4.jar!/:2.7.4]
2022-10-04T10:56:32.114996500Z at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:734) ~[spring-boot-2.7.4.jar!/:2.7.4]
2022-10-04T10:56:32.114999200Z at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:408) ~[spring-boot-2.7.4.jar!/:2.7.4]
2022-10-04T10:56:32.115001900Z at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) ~[spring-boot-2.7.4.jar!/:2.7.4]
2022-10-04T10:56:32.115004500Z at org.springframework.boot.SpringApplication.run(SpringApplication.java:1306) ~[spring-boot-2.7.4.jar!/:2.7.4]
2022-10-04T10:56:32.115007100Z at org.springframework.boot.SpringApplication.run(SpringApplication.java:1295) ~[spring-boot-2.7.4.jar!/:2.7.4]
2022-10-04T10:56:32.115009800Z at xxxxxxxxxxxxxxxxxx.MyApplication.main(DockerAtmApplication.java:10) ~[classes!/:na]
2022-10-04T10:56:32.115012400Z at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_212]
2022-10-04T10:56:32.115015400Z at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_212]
2022-10-04T10:56:32.115019000Z at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_212]
2022-10-04T10:56:32.115022800Z at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_212]
2022-10-04T10:56:32.115026200Z at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:49) ~[app.jar:na]
2022-10-04T10:56:32.115030000Z at org.springframework.boot.loader.Launcher.launch(Launcher.java:108) ~[app.jar:na]
2022-10-04T10:56:32.115033800Z at org.springframework.boot.loader.Launcher.launch(Launcher.java:58) ~[app.jar:na]
2022-10-04T10:56:32.115037700Z at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:65) ~[app.jar:na]
2022-10-04T10:56:32.115040500Z Caused by: java.net.UnknownHostException: some-postgres
2022-10-04T10:56:32.115046600Z at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:184) ~[na:1.8.0_212]
2022-10-04T10:56:32.115053400Z at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:1.8.0_212]
2022-10-04T10:56:32.115056900Z at java.net.Socket.connect(Socket.java:589) ~[na:1.8.0_212]
2022-10-04T10:56:32.115059500Z at org.postgresql.core.PGStream.createSocket(PGStream.java:241) ~[postgresql-42.5.0.jar!/:42.5.0]
2022-10-04T10:56:32.115062000Z at org.postgresql.core.PGStream.<init>(PGStream.java:98) ~[postgresql-42.5.0.jar!/:42.5.0]
2022-10-04T10:56:32.115064800Z at org.postgresql.core.v3.ConnectionFactoryImpl.tryConnect(ConnectionFactoryImpl.java:109) ~[postgresql-42.5.0.jar!/:42.5.0]
2022-10-04T10:56:32.115067600Z at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:235) ~[postgresql-42.5.0.jar!/:42.5.0]
2022-10-04T10:56:32.115070400Z ... 57 common frames omitted
Here's my Dockerfile:
FROM openjdk:8-jdk-alpine
ARG JAR_FILE=build/libs/*-SNAPSHOT.jar
COPY ${JAR_FILE} app.jar
EXPOSE 8081
ENTRYPOINT ["java", "-jar", "/app.jar"]
And here's my docker-compose.yaml:
services:
webapp:
build:
context: .
dockerfile: Dockerfile
ports:
- "8081:8081"
postgres:
container_name: postgres
image: postgres
environment:
POSTGRES_USER: postgres
POSTGRES_PASSWORD: password!
PGDATA: /data/postgres
volumes:
- postgres:/data/postgres
ports:
- "5432:5432" #maps the host's port 5432 to the container's port 5432
networks:
- postgres
restart: unless-stopped
pgadmin: #access this on localhost:5050
container_name: pgadmin_container
image: dpage/pgadmin4
environment:
PGADMIN_DEFAULT_EMAIL: ${PGADMIN_DEFAULT_EMAIL:-pgadmin4#pgadmin.org}
PGADMIN_DEFAULT_PASSWORD: ${PGADMIN_DEFAULT_PASSWORD:-admin}
PGADMIN_CONFIG_SERVER_MODE: 'False'
volumes:
- pgadmin:/var/lib/pgadmin
ports:
- "5050:80"
networks:
- postgres
restart: unless-stopped
networks:
postgres:
driver: bridge
volumes:
postgres:
pgadmin:
I've tried a Gradle refresh, I've tried rebuilding the whole project, I've tried docker-compose build --no-cache, I've even tried the "nuclear option" of docker system prune, but no matter what, this one Docker image keeps haunting my code.
EDIT: Here's the application.properties file I'm using:
server.port=8081
spring.datasource.url=jdbc:postgresql://localhost:5432/docker_atm
spring.datasource.username=postgres
spring.datasource.password=password!
spring.jpa.properties.hibernate.jdbc.lob.non_contextual_creation=true
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect
#Database initialisation - change to "validate" when in production
spring.jpa.hibernate.ddl-auto=update

Answer 1

In your docker-compose.yml under the following part
postgres:
container_name: postgres
image: postgres
you have named the database service as postgres. So by default docker will expose a host as ...postgres...
But from Spring-boot application it seems you try to connect to host some-postgres.
2022-10-04T10:56:32.115040500Z Caused by: java.net.UnknownHostException: some-postgres
The configuration that spring boot app has as you mention is jdbc:postgresql://some-postgres:5432/docker_atm
So to fix the situation you have 2 options:
change the spring boot configuration into jdbc:postgresql://postgres:5432/docker_atm
keep the existing spring boot configuration url property jdbc:postgresql://some-postgres:5432/docker_atm and change the docker-compose.yml into
some-postgres:
container_name: postgres
image: postgres
so that the host available becomes the some-postgres.
Edit:
As to provide a clear specific solution please do the following.
Modify your compose.yml with the following
some-postgres: <---------------------
container_name: postgres
image: postgres
environment:
POSTGRES_DB: docker_atm <-------------
POSTGRES_USER: postgres
POSTGRES_PASSWORD: password!
PGDATA: /data/postgres
volumes:
- postgres:/data/postgres
ports:
- "5432:5432" #maps the host's port 5432 to the container's port 5432
networks:
- postgres
restart: unless-stopped
.....
You have also forgot to declare in your docker the database name for your postgresql instance.
Then your spring boot application property should be
spring.datasource.url=jdbc:postgresql://some-postgres:5432/docker_atm
Rebuild the docker image and the jar for the application and repackage and redeploy and it shall work.