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Meaning of SPRING.ZIPKIN.BASEURL: http://zipkin-server:9411 [duplicate]

I am new to Docker. I am trying to dockerize my Spring Boot application but getting the error
connection to localhost:5432 refused .
The Spring Boot application has a postgresql db connection and uses random port to run on Tomcat.
Please find the details below, requesting to please check and help in resolving the issue. Please give a detailed solution as I am new to Docker.
Dockerfile
FROM openjdk:8-jdk-alpine
ARG JAR_FILE=target/SpringConversionFactor-0.0.1-SNAPSHOT.jar
WORKDIR /opt/app
COPY ${JAR_FILE} app.jar
ENTRYPOINT ["java","-jar","app.jar"]
Docker run
docker run springconversionfactor
Exception
Connection to localost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections

When you are running any application in docker it gets isolated from your existing environment.Here you are running spring boot application in docker and provided postgresql url as localhost:5432,because of that your spring boot application is finding postgres db inside your spring boot docker container.Please make sure where your postgres db is running.If it is running on your server give url as server_ip:5432 or if it is running in other conatiner then give it as container_name:5432 (here you can do port mapping with your server also).

Spring Boot, using oracle-ldap url through ssh tunnel on local machine

There are 3 machines:
local -> some remote server -> oracle db server (via ldap)
I want to set up datasource connection (in my spring boot app) to the oracle db.
There is no direct connectivity between local machine and the one with oracle db.
So, i'm using the ssh tunnel through remote server:
ssh -L 127.0.0.1:8081:some.ldap.host:389 user#remote.server.host
In application.yml file i'm using further url:
spring:
datasource:
url: jdbc:oracle:thin:#ldap://127.0.0.1:8081//srvcnm,cn=OracleContext,dc=yy,dc=xx,dc=com
And when my app trying to get db connection, im getting the following error:
Caused by: oracle.net.nt.TimeoutInterruptHandler$IOReadTimeoutException: Socket read timed out
at oracle.net.nt.TimeoutSocketChannel.handleInterrupt(TimeoutSocketChannel.java:254)
at oracle.net.nt.TimeoutSocketChannel.connect(TimeoutSocketChannel.java:103)
at oracle.net.nt.TimeoutSocketChannel.<init>(TimeoutSocketChannel.java:77)
at oracle.net.nt.TcpNTAdapter.connect(TcpNTAdapter.java:192)
... 126 common frames omitted
Whenever i'm deploying app on the remote server and enter "direct" url in application.yml the connection is being obtained without any timeouts, and the app works well.
jdbc:oracle:thin:#ldap://some.ldap.host:389//srvcnm,cn=OracleContext,dc=yy,dc=xx,dc=com
Does anyone know how to handle this? How to get connection from local machine?

I may do some thing like this, I am going to create file call ~/.ssh/config then add following
Host remoteserver1
User usermane
Hostname ip or host name
ForwardAgent yes
Host oracleserver
User username
Hostname some.ldap.host
Port 22
# ForwardAgent yes if you need to forward one more instance
LocalForward 8081 some.ldap.host:389
ProxyCommand ssh -q -W %h:%p remoteserver1
What this does is that when I attempt to connect to ssh oracleserver from remoteserver1, it connects to hopper and then proxies the SSH connection to port 22 on overthere (ie: SSH on oracleserver).
now to connect via ssh do following ssh oracleserver , as it will make ssh tunnel between your machine and oracleserver via remoteserver1. along with port forwarding.

The problem was in redirecting source connection request to another machine with oracle db itself (after ldap auth).
So, the request's path looked like:
1.local -> 2.remote server -> 3.ldap server -> 4.oracle db server
There wasn't connectivity between 1st and 4th machine as the tunnel was only between 1th and 3rd one.
So, you if you faced this issue, you may add one more ssh tunnel (First tunnel is for ldap server, second one for oracle db) and enrich your "etc/hosts" with oracle server's routing.
In my case the issue was in access restrictions. The oracle server is filtering sockets somehow and grants access to certain machines.

Cannot connect to remote MSSQL database from stacked docker container

I have a problem with connecting to existing remote MSSQL database from inside of a docker container running in stack.
My application consists of three modules (backend, frontend and haproxy)
Backend module is written in Java (SpringBoot app) and it's also the one that needs to connect do remote MSSQL database (by remote I mean placed on different sever, separate of docker part).
I have the following docker compose file:
I start the stack by using following command:
docker stack deploy -c docker-compose.yml myapp
The result is, all containers are up and running, but spring app reports that connection to DB is timed out:
Server seems to be configured properly, I am able to access the host from container through telnet.
When running independently (even from docker container) backend app is able to connect to database with no problems, while stacked with docker-compose however it's unable to connect to the very same db.
I've also tried to provide db server IP instead of host name - no success.
Maybe setting up networks section in docker compose would do the trick?

UPDATE
Another thing you can do is to use host.docker.internal instead of the IP address of the database. This ONLY works on docker for windows or docker for mac.
Source: I want to connect from a container to a service on the host
OLD, only works when not in swarm mode
You need to specify that docker should use the same network as the host, you can do this in the following way:
version: '3'
services:
web-app:
build:
dockerfile: web-app/something
ports:
- 8080:8080
network_mode: "host"
Reference: Use host networking

It seems that the issue was caused by networks overlapping.
Adding network configured as show below, allowed either to connect to my remote database and keep my endpoints hidden:
networks:
backend:
ipam:
driver: default
config:
- subnet: 192.168.40.0/26

Connection refused from docker (in swarm)

I have a docker swarm setup with services registered in an overlay network. Comunication between services is working fine however I get a "Connection refused" from one of my services that connects to an external DB. The service is a Java based application (spring boot).
The connection is defined with its IP (jdbc:mysql://192.168.130.141:3306/database?autoReconnect=true)
I have checked that I can ping the server from the container docker exec -it e093 ping 192.168.130.141 gives expected answer
I have rechecked (4 times) my credentials
I can connect to the DB from the host
Host is Ubuntu 16.04.4 LTS
I am running docker 18.03.0-ce and the exact error is
java.net.ConnectException: Connection refused (Connection refused)
at java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:1.8.0_151]
I'll skip the full stack trace here.
Any help would be greatly appreciated
--EDIT--
Let me clarify that the database is a Galera cluster and the IP I try to connect to is the load balancer (HAProxy) in front of it. I know the setup works as I have other applications connecting to the cluster in this matter as well as the service itself (when not in a docker container).
So, as far as I can tell, my connection informations are correct but it doesn't connect from inside docker services.

Can you show your docker-compose.yml? In the ports you have to expose the port that you need to access.
ports:
- 3306:3306
You can install telnet to test if the port is open using this commands inside the container
docker container ls
docker exec -it conainerid bash
apt-get update
apt-get install telnet

Trouble communicating between two docker containers

I’m new to docker and I’m trying to connect my spring boot app running into my boot-example docker container to a mysql server running into my mymysql docker container on port 6603, both running on the same phisical machine.
The fact is: if I connect my spring-boot app to my mymysql docker container in order to communicate with the database, I get no errors and everything works fine.
When I move my spring boot application into my boot-example container and try to communicate (through Hibernate) to my mymysql container, then I get this error:
2018-02-05 09:58:38.912 ERROR 1 --- [ main] o.a.tomcat.jdbc.pool.ConnectionPool : Unable to create initial connections of pool.
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: 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 sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_111]
My spring boot application.properties are:
server.port=8083
spring.jpa.hibernate.ddl-auto=create-drop
spring.datasource.url=jdbc:mysql://localhost:6603/mydockerdb
spring.datasource.username=root
spring.datasource.password=mypassword
It works fine until my spring boot app runs in a docker container on port 8082, (after the docker image is correctly built):
docker run -it -p 8082:8083 boot-example

You cannot use localhost inside the container, it's the container itself. Hence, you will always get the connection refused error.
You can do below things -
Add your host machine IP in application.properties file of your spring boot application. (Not recommended since it breaks docker portability logic)
In case you want to use localhost, use --net=host while starting the container. (Not recommended for Production since no logical network layer exists)
Use --links for container communication with a DNS name. (deprecated/legacy)
Create a compose file & call your DB from spring boot app with the service name since they will be in same network & highly integrated with each other. (Recommended)
PS - Whenever you need to integrate multiple containers together, always go for docker-compose version 3+. Use docker run|build to understand the fundamentals & performing dry/test runs.

As #vivekyad4v suggested - the easiest way to achieve your desire, is to use docker-compose which has better container communication integration.
Docker-compose is a tool for managing single or multiple docker container/s. It uses single configuration file called docker-compose.yml.
For better information about docker-compose, please take a look at documentation and compose file reference
In my experience, it is good practice to follow SRP (single responsibility principle), thus - creating one container for your database and one for your application. Both of them are communicating using network you specify in your configuration.
Following example of docker-compose.yml might help you:
version: '2'
networks:
# your network name
somename:
driver: bridge
services:
# PHP server
php:
image: dalten/php5.6-apache
ports:
- 80:80
volumes:
- .application_path:/some/application/path
# your container network name defined at the beggining
networks:
- somename
# Mysql server for backend
mysql:
image: dalten/mysql:dev
ports:
- 3306:3306
# The /var/lib/mysql volume MUST be specified to achieve data persistence over container restart
volumes:
- ./mysql_data:/var/lib/mysql
environment:
MYSQL_ROOT_PASSWORD: root
MYSQL_DATABASE: backend
# your container network name defined at the beggining
networks:
- somename
Note: Communication between containers inside network can be achieved by calling the service name from inside container.
The connection parameters to MySQL container from PHP, would in this example be:
hostname: mysql
port: 3306
database: backend
user: root
password: root

As per above suggestion, Docker-compose is a way but if you don't want to go with compose/swarm mode.
Simply create your own network using docker network create myNet
Deploy your containers listening on a created network --network myNet
Change your spring.datasource.url to jdbc:mysql://mymysql:6603/mydockerdb
By using DNS resolution of docker demon, containers can discover each other and hence can communicate.
[DNS is not supported by default bridge. A user-defined network using bridge does.]
For more information: https://docs.docker.com/engine/userguide/networking/