I have a postgres image running my database and I run this as a Docker container and I can connect to it from psql, but when I connect to it from my application server, I get the following error:
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.
cpo-platform-server-cpo-platform-1 | at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:342)
cpo-platform-server-cpo-platform-1 | at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:54)
cpo-platform-server-cpo-platform-1 | at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:263)
cpo-platform-server-cpo-platform-1 | at org.postgresql.Driver.makeConnection(Driver.java:443)
cpo-platform-server-cpo-platform-1 | at org.postgresql.Driver.connect(Driver.java:297)
cpo-platform-server-cpo-platform-1 | at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:677)
cpo-platform-server-cpo-platform-1 | at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:228)
cpo-platform-server-cpo-platform-1 | at doobie.util.transactor$Transactor$FromDriverManagerUnapplied.$anonfun$apply$19(transactor.scala:378)
cpo-platform-server-cpo-platform-1 | at doobie.util.transactor$Transactor$FromDriverManagerUnapplied.$anonfun$create$2(transactor.scala:347)
cpo-platform-server-cpo-platform-1 | at blocking @ doobie.util.transactor$Transactor$FromDriverManagerUnapplied.$anonfun$create$1(transactor.scala:347)
cpo-platform-server-cpo-platform-1 | at fromAutoCloseable @ doobie.util.transactor$Transactor$FromDriverManagerUnapplied.$anonfun$create$1(transactor.scala:347)
cpo-platform-server-cpo-platform-1 | at fromAutoCloseable @ doobie.util.transactor$Transactor$FromDriverManagerUnapplied.$anonfun$create$1(transactor.scala:347)
cpo-platform-server-cpo-platform-1 | at use @ doobie.util.transactor$Transactor$$anon$4.apply(transactor.scala:164)
Is there anything that I have to watch out for when connecting from one Docker container where my application server is running to another Docker container where my database is running? I use the docker compose to start both of them like this:
services:
my-app:
image: me/my-app-server:1.1-SNAPSHOT
ports:
- 127.0.0.1:9000:9000
environment:
configEnv: test
my-db:
image: my-db-postgres-test-container
ports:
- 127.0.0.1:5432:5432
After starting, I can connect to the database using psql, but connecting via my application server fails. The credentials, database server etc., are all correctly configured, but still it won’t connect. Any ideas?
>Solution :
When you have two containers started, exposed ports for the host are not exposed across containers.
Use the hostname of the postgres container, my-db in your case, instead of localhost, to connect from my-app.