Develop Reference

Docker doesn't save permanently files, which create my java app

My java app (backend) create some files during work. And when i make rebuild after some changes, this file deletes and my app need to create it again. How to save this files permanently? I try to create volume but it doesn't work.
This is my docker-compose config:
version: '3'
services:
examledb:
container_name: examle-docker-db
image: postgres
volumes:
- examle-docker-db:/var/lib/postgresql/data
ports:
- "5555:5432"
expose:
- "5555"
environment:
- POSTGRES_PASSWORD=password
- POSTGRES_USER=postgres
- POSTGRES_DB=examle
- PGDATA=/var/lib/postgresql/data/pgdata
networks:
- examle-docker-network
restart: unless-stopped
backend:
container_name: examle-docker-backend
build: ./backend
volumes:
- /var/lib/docker/volumes/example_prod_example-backend-volume/_data:/root/projects/example_PROD/backend
ports:
- "8080:8080"
- "8888:8888"
depends_on:
- examledb
networks:
- examle-docker-network
environment:
SPRING_DATASOURCE_URL: jdbc:postgresql://examle-docker-db:5432/examle
restart: unless-stopped
frontend:
container_name: examle-docker-frontend
build: ./frontend
restart: unless-stopped
command: serve -s dist/vu4y-frontend -l 4200
networks:
- examle-docker-network
nginx:
image: nginx:stable
container_name: examle-docker-nginx
ports:
- "80:80"
- "443:443"
volumes:
- ./data/nginx:/etc/nginx/conf.d
- ./data/certbot/conf:/etc/letsencrypt
- ./data/certbot/www:/var/www/certbot
depends_on:
- frontend
- backend
networks:
- examle-docker-network
command: "/bin/sh -c 'while :; do sleep 6h & wait $${!}; nginx -s reload; done & nginx -g \"daemon off;\"'"
certbot:
image: certbot/certbot
restart: unless-stopped
volumes:
- ./data/certbot/conf:/etc/letsencrypt
- ./data/certbot/www:/var/www/certbot
networks:
- examle-docker-network
entrypoint: "/bin/sh -c 'trap exit TERM; while :; do certbot renew; sleep 12h & wait $${!}; done;'"
volumes:
examle-docker-db: { }
networks:
examle-docker-network:
driver: bridge
Also I try to create volume like this:
volumes:
- example-backend-volume:/root/projects/example_PROD/backend
It also doesn't work.
My docker-compose.yml layout in /root/projects/Example
Any advice will be very helpful. All files creates inside backend folder in the same category with src and pom.xml.

I solved the problem. My problem was that I don't understand how docker's volume works. I thought that need to write root where my docker app is run, but need to write any path in right path (in my case /root/projects/example_PROD/backend) and saves files in app there.

IntelliJ and Docker: Create a remote debug configuration: custom command

I am trying to run my java application (a project at my uni) in debug mode in IntelliJ with a dockerfile.
I found this tutorial:
https://www.jetbrains.com/help/idea/debug-a-java-application-using-a-dockerfile.html#create-remote-debug-config
I tried to follow each step (#create-remote-debug-configuration), but at 4:
Select the Docker configuration that runs your app (MyPassApp) and
specify the command to use when running your app in the Custom Command
field. The remote debug configuration will use this custom command
instead of the one defined in the Dockerfile. This command should
contain the -agentlib option to let the debugger attach to the
process:
java -agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=5005 -jar JavaPassFromConsole.jar
I don't know what any of those commands mean, so I dont know what to put in the custom command section.
This is my docker-compose.yml file:
version: '3'
volumes: mysql_data: {}
networks:
back:
services:
backend:
build:
context: '.'
dockerfile: 'docker_config/backend/Dockerfile'
depends_on:
- db
links:
- db
ports:
- 8080:8080
- 9990:9990
environment:
CONTACT_USERNAME: <XXX>
CONTACT_PASSWORD: <XXX>
networks:
- back db:
container_name: db
image: mysql:5.7
restart: always
volumes:
- mysql_data:/var/lib/mysql
command: --lower_case_table_names=1
environment:
MYSQL_DATABASE: <XXX>
MYSQL_ROOT_PASSWORD: root
networks:
- back
ports:
- 3306:3306
- 5005:5005 phpmyadmin:
depends_on:
- db
image: phpmyadmin/phpmyadmin
restart: always
ports:
- 4000:80
environment:
MYSQL_ROOT_PASSWORD: root
networks:
- back
Any help is appreciated!!

Make HTTP request from one container to another

I am trying to do a httpRequest from library to people-service, but not that i've tried works.
i saw that if use the name it shoud ork, so i have tried http://library:8080, but it returns the error
java.lang.IllegalArgumentException: unsupported URI
Here is my Dockerfile:
FROM openjdk:11-jdk-slim
ARG JAR_FILE
COPY ${JAR_FILE} app.jar
ENTRYPOINT ["java","-jar","/app.jar"]
and my docker-compose:
version: '3.5'
services:
library:
build:
context: ./
ports:
- "8081:8081"
networks:
- library-network
restart: on-failure
mysql-service:
image: mysql:5.7
ports:
- "3306:3306"
networks:
- library-network
environment:
- MYSQL_ROOT_PASSWORD=admin
- MYSQL_USER=admin
- MYSQL_PASSWORD=admin
- MYSQL_DATABASE=bootdb
restart: on-failure
people-service:
build:
context: ./
args:
JAR_FILE: ./target/library.jar
ports:
- "8080:8080"
environment:
- DB_HOST=jdbc:mysql://mysql-service:3306/library
networks:
- library-network
depends_on:
- mysql-service
- library
restart: on-failure
networks:
library-network:
driver: bridge

Your question says:
I am trying to do a httpRequest from library to people-service
From that I assume the request would be initiated in library. Then the URL should look like http://people-service:8080.
But from the error message I'd assume your library is not able to run http requests - regardless of where they are going to, which is a bit strange. Investigate on that first, using simple urls like http://stackoverflow.com (which will return http status 301).

Keycloak docker container throws `java.net.UnknownHostException` during startup

I'm trying to setup a keycloak container on my docker host. Unfortunately the keycloak container can't connect to my db container and always throws a java.net.UnknownHostException.
My docker-compose file:
version: '2'
services:
keycloak:
image: quay.io/keycloak/keycloak:latest
container_name: keycloak
restart: always
networks:
- webgateway
- keycloak-net
environment:
- DB_VENDOR=MYSQL
- DB_ADDR=keycloak-db
- DB_DATABASE=keycloak
- DB_USER=keycloak
- DB_PASSWORD=password
- KEYCLOAK_USER=admin
- KEYCLOAK_PASSWORD=password
depends_on:
- keycloak-db
keycloak-db:
image: mysql:5.7
container_name: keycloak-db
restart: always
volumes:
- /var/keycloak/database:/var/lib/mysql
networks:
- keycloak-net
environment:
- MYSQL_ROOT_PASSWORD=root
- MYSQL_DATABASE=keycloak
- MYSQL_USER=keycloak
- MYSQL_PASSWORD=password
networks:
keycloak-net:
webgateway:
external:
name: docker_webgateway
The error message:
Caused by: java.net.UnknownHostException: keycloak-db: Name or service not known,
at java.base/java.net.Inet4AddressImpl.lookupAllHostAddr(Native Method),
at java.base/java.net.InetAddress$PlatformNameService.lookupAllHostAddr(InetAddress.java:929),
at java.base/java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1515),
at java.base/java.net.InetAddress$NameServiceAddresses.get(InetAddress.java:848),
at java.base/java.net.InetAddress.getAllByName0(InetAddress.java:1505),
at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1364),
at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1298),
at com.mysql.jdbc#8.0.19//com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:132),
at com.mysql.jdbc#8.0.19//com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:65),
... 64 more,
,
23:44:04,490 FATAL [org.keycloak.services] (ServerService Thread Pool -- 72) java.lang.RuntimeException: Failed to connect to database,
Does someone know what I'm doing wrong?
P.S. The docker host is running locally so don't worry about my weak passwords.

Flag depends_on only ensures the order in which container is started but not whether the container is ready to serve the requests or not and that's what is happening here, where SQL container is started but it's not ready to receive the requests as it takes time. Please follow the below commands and the file, in which I added the health checks as well in docker-compose and you need to change the version to 2.1 or higher.
Create an external docker network
docker network create docker_webgateway
docker-compose.yaml
container_name: keycloak
restart: always
networks:
- webgateway
- keycloak-net
environment:
- DB_VENDOR=MYSQL
- DB_ADDR=keycloak-db
- DB_DATABASE=keycloak
- DB_USER=keycloak
- DB_PASSWORD=password
- KEYCLOAK_USER=admin
- KEYCLOAK_PASSWORD=password
depends_on:
- keycloak-db
keycloak-db:
image: mysql:5.7
container_name: keycloak-db
restart: always
healthcheck:
test: ["CMD", "mysqladmin" ,"ping", "-h", "localhost"]
timeout: 20s
retries: 10
volumes:
- /var/keycloak/database:/var/lib/mysql
networks:
- keycloak-net
environment:
- MYSQL_ROOT_PASSWORD=root
- MYSQL_DATABASE=keycloak
- MYSQL_USER=keycloak
- MYSQL_PASSWORD=password
networks:
keycloak-net:
webgateway:
external:
name: docker_webgateway
Create the stack by running the below command
docker-compose up

Zuul Load Balancer

So I have little problem here. I have 4 module:
Eureka Server
Zuul Gateway
Authentication Service
Another MicroService
When I starting it on a local computer it doesn't show any problem like
Caused by: com.netflix.client.ClientException: Load balancer does not have available server for client: authentication-service
But when I started building it on docker it's always getting error like that. Can you tell me the part that I'm wrong?
eureka server properties
spring.application.name=bms-server
# default port for eureka server
server.port=8761
eureka.instance.hostname=bms-server
# eureka by default will register itself as a client. So, we need to set it to false.
# What's a client server? See other microservices (student, auth, etc).
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false
Zuul Server properties
server.port=8762
spring.application.name=bms-api-gateway
eureka.client.fetch-registry=true
eureka.client.service-url.defaultZone=http://bms-server:8761/eureka/
zuul.ignored-services=*
zuul.routes.authentication-service.path=/auth/**
zuul.routes.authentication-service.service-id=authentication-service
zuul.routes.general-setup-service.path=/general-setup/**
zuul.routes.general-setup-service.service-id=general-setup-service
zuul.routes.authentication-service.strip-prefix=false
zuul.routes.authentication-service.sensitive-headers=Cookie,Set-Cookie
zuul.retryable=true
zuul.ignored-headers=Access-Control-Allow-Credentials, Access-Control-Allow-Origin
ribbon.eureka.enabled=false
ribbon.ConnectTimeout=60000
ribbon.ReadTimeout=60000
hystrix.command.default.execution.enabled=false
hystrix.command.default.execution.isolation.strategy=THREAD
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds=240000
Authentication service properties
spring.application.name=authentication-service
server.port=9100
eureka.client.service-url.defaultZone=http://bms-server:8761/eureka/
authentication-service.ribbon.listOfServers=http://localhost:9100
spring.cloud.loadbalancer.ribbon.enabled=false
this is my Another service properties
spring.application.name=authentication-service
server.port=9100
eureka.client.service-url.defaultZone=http://bms-server:8761/eureka/
general-setup-service.ribbon.listOfServers=http://localhost:9100
spring.cloud.loadbalancer.ribbon.enabled=false
And last this is my docker-compose.yml
version: '3.5'
services:
bms-server:
image: bms-server:v1
container_name: bms-server
hostname: bms-server
build:
context: ./bms-server
dockerfile: Dockerfile
volumes:
- maven-home:/root/.m2
ports:
- "8761:8761"
networks:
- bms-network
bms-api-gateway:
image: bms-api-gateway:v1
container_name: bms-api-gateway
build:
context: ./bms-api-gateway
dockerfile: Dockerfile
ports:
- "8762:8762"
depends_on:
- bms-server
volumes:
- maven-home:/root/.m2
links:
- bms-server:bms-server
hostname: bms-api-gateway
networks:
- bms-network
bms-authentication-service:
image: bms-authentication-service:v1
container_name: bms-authentication-service
build:
context: ./bms-authentication-service
dockerfile: Dockerfile
ports:
- "9100:9100"
volumes:
- maven-home:/root/.m2
depends_on:
- bms-server
links:
- bms-server:bms-server
hostname: authentication-service
networks:
- bms-network
bms-general-setup-service:
image: bms-general-setup-service:v1
container_name: bms-general-setup-service
build:
context: ./bms-general-setup-service
dockerfile: Dockerfile
ports:
- "9102:9102"
depends_on:
- bms-server
links:
- bms-server:bms-server
volumes:
- maven-home:/root/.m2
hostname: general-setup-service
networks:
- bms-network
volumes:
maven-home:
networks:
bms-network:
name: bms-network
driver: bridge
Please tell me the part that I'm wrong. Thank you very much.