I need to connect spring boot application in one docker container to a Cassandra database in another container.
There are two ways.
"scripted" approach, where you first docker run cassandra container, then you docker run your app. You have to make sure first container exposes ports second container can connect to, or while starting second container reference ports from first by name
use docker compose, that should more or less look like this:
version: '2'
services:
cassandra:
image: cassandra:3.11.5
ports:
- 7000:7000
springapp:
image: springapp:latest
ports:
- 8080:8080
environment:
CASSANDRA_CONTACTPOINTS: 127.0.0.1
CASSANDRA_PORT: 7000
Related
I have a problem here that I really cannot understand. I already saw few topics here with the same problem and those topics was successfully solved. I basically did the same thing and cannot understand what I'm doing wrong.
I have a Spring application container that tries to connect to a Mongo container through the following Docker Composer:
version: '3'
services:
app:
build: .
ports:
- "8080:8080"
links:
- db
db:
image: mongo
volumes:
- ./database:/data
ports:
- "27017:27017"
In my application.properties:
spring.data.mongodb.uri=mongodb://db:27017/app
Finally, my Dockerfile:
FROM eclipse-temurin:11-jre-alpine
WORKDIR /home/java
RUN mkdir /home/java/bar
COPY ./build/libs/foo.jar /home/java/bar/foo.jar
CMD ["java","-jar", "/home/java/bar/foo.jar"]
When I run docker compose up --build I got:
2022-11-17 12:08:53.452 INFO 1 --- [null'}-db:27017] org.mongodb.driver.cluster : Exception in monitor thread while connecting to server db:27017
Caused by: java.net.UnknownHostException: db
Running the docker compose ps I can see the mongo container running well, and I am able to connect to it through Mongo Compass and with this same Spring Application but outside of container. The difference running outside of container is the host from spring.data.mongodb.uri=mongodb://db:27017/app to spring.data.mongodb.uri=mongodb://localhost:27017/app.
Also, I already tried to change the host for localhost inside of the spring container and didnt work.
You need to specify MongoDB host, port and database as different parameters as mentioned here.
spring.data.mongodb.host=db
spring.data.mongodb.port=27017
spring.data.mongodb.authentication-database=admin
As per the official docker-compose documentation the above docker-compose file should worked since both db and app are in the same network (You can check if they are in different networks just in case)
If the networking is not working, as a workaround, instead of using localhost inside the spring container, use the server's IP, i.e, mongodb://<server_ip>:27017/app (And make sure there is no firewall blocking it)
I'm pretty new to docker, and I've tried searching about networking but haven't found a solution that's worked.
I have a Laravel app that is using Laradock.
I also have an external 3rd party API that runs in its own docker container.
I basically want to specify the container name of the api inside my laravel .env file, and have it dynamically resolve the container ip so I can make API calls from my Laravel app. I can already do this with services that are already part of laradock like mariadb/mysql, but since my API is located in an external container, it can't connect to it.
I tried making a network and attaching them with;
docker network create my-network
Then inside my docker-compose.yml files for each of the containers, I specified;
networks:
my-network:
name: "my-network"
But if I try and ping them with;
docker exec -ti laradock-workspace-1 ping my-api
I can't connect and can't really figure out why. Was hoping someone familiar with docker might be able to explain why since I'm sure it's something very obvious I'm missing. Thanks!
By default Docker Compose uses a bridge network to provision inter-container communication. Read this article for more info about inter-container networking.
What matters for you, is that by default Docker Compose creates a hostname that equals the service name in the docker-compose.yml file.
Consider the following docker-compose.yml:
version: '3.9'
services:
server:
image: node:16.9.0
container_name: server
tty: true
stdin_open: true
depends_on:
- mongo
command: bash
mongo:
image: mongo
environment:
MONGO_INITDB_DATABASE: my-database
When you run docker-compose up, Docker will create a default network and assigns the service name as hostname for both mongo and server.
You can now access the backend container via:
docker exec -it server bash
And now you can ping the mongo container using Dockers internal network (default on port 27017 in this case):
curl -v http://mongo:27017/my-database
That's it. The same applies for your setup.
I have created a spring app and i want to connect it to redis server which is deployed on docker-compose i put the needed properties as follow :
spring.redis.host=redis
spring.redis.port=6379
But i keep getting a ConnexionException so how can i Know on which host redis is running and how to connect to it.
Here is my docker-compose file :
version: '2'
services:
redis:
image: 'bitnami/redis:5.0'
environment:
# ALLOW_EMPTY_PASSWORD is recommended only for development.
- ALLOW_EMPTY_PASSWORD=yes
- REDIS_DISABLE_COMMANDS=FLUSHDB,FLUSHALL
ports:
- '6379:6379'
volumes:
- 'redis_data:/bitnami/redis/data'
volumes:
redis_data:
driver: local
From docker compose documentation
By default Compose sets up a single network for your app. Each container for a service joins the default network and is both reachable by other containers on that network, and discoverable by them at a hostname identical to the container name
If you want to access redis by container name ('redis' in this case), the Spring boot application has also be deployed as a docker compose service, but it doesn't appear in the docker-compose file that you've provided in the question, so please add it.
Alternatively If you're trying to run the spring boot application on host machine, use 'localhost' instead of 'redis' in order to access the redis container.
Another approach you can use is "docker network" , Below are the steps to follow :
Create a docker network for redis
docker network create redis-docker
Spin up redis container is redis-docker network.
docker run -d --net redis-docker --name redis-stack -p 6379:6379 -p 8001:8001 redis/redis-stack:latest
Inspect the redis-docker container
docker network inspect redis-docker
Copy the "IPv4Address" IP and paster in application.yml
Now build , start your application.
I have two docker containers, one with hazelcast java application (the core for the web application - jar package) and one with rest service for the web application (war package). I'm using docker-compose to build up whole project in docker which looks like this:
version: "3"
services:
escomled_datagrid:
image: escomled/escomled_datagrid
build:
context: ./sh_scripts/escomled_data_grid
tomcat:
image: escomled/tomcat
build:
context: ./tomcat/app
ports:
- 8585:8080
depends_on:
- escomled_datagrid
links:
- escomled_datagrid:escomled_datagrid
I also have Dockerfile for each container:
-escomled_datagrid:
FROM openjdk:8-jdk-alpine as build
WORKDIR /EscomledML
COPY ./. ./
COPY ./escomled.properties
/home/escomled/escomled_server/config/escomled.properties
CMD ["sh","/EscomledML/escomled_data_grid.sh","start"]
EXPOSE 8085
-tomcat
FROM tomcat:8.5-alpine
COPY ./sample.war /usr/local/tomcat/webapps/
COPY ./escomled-rest.war /usr/local/tomcat/webapps/
COPY ./escomled.properties
/home/escomled/escomled_server/config/escomled.properties
RUN sh -c 'touch /usr/local/tomcat/webapps/sample.war'
RUN sh -c 'touch /usr/local/tomcat/webapps/escomled-rest.war'
EXPOSE 8080
First container uses sh script in the runtime.
This way everyting works fine, the containers start and stay active.
The only problem is that they dont see each other, hazelcast server starts and waits for "member" to connect, war file (hazelcast member) also starts, but they dont "see" each other and wont connect. I put in the docker-compose file "links" and "depends on" tags, but that wont help.
The code for the project works fine when I start it localy, first I start data grid server as java application, then I start the tomcat containing rest service and the connection is established in no time.
So my question is, how do I link this two containers so they can see each other and work together?
try putting the containers in the same "network" by specifying the network bridge
version: "3"
services:
escomled_datagrid:
image: escomled/escomled_datagrid
build:
context: ./sh_scripts/escomled_data_grid
networks:
- networknamename
tomcat:
image: escomled/tomcat
build:
context: ./tomcat/app
ports:
- 8585:8080
depends_on:
- escomled_datagrid
links:
- escomled_datagrid:escomled_datagrid
networks:
- networknamename
networks:
networknamename:
driver: bridge
TL;DR: How do I have to change my below docker-compose.yml in order to allow one container to use a service of another over a custom (non-standard) port?
I have a pretty common setup: containers for a web app (Padrino [Ruby]), Postgres, Redis, and a queueing framework (Sidekiq). The web app comes with its custom Dockerfile, the remaining services come either from standard images (Postgres, Redis), or mount the data from the web app (Sidekiq). They are ties together via the following docker-compose.yml:
version: '2'
services:
web:
build: .
command: 'bundle exec puma -C config/puma.rb'
volumes:
- .:/myapp
ports:
- "9000:3000"
depends_on:
- postgres
- redis
sidekiq:
build: .
command: 'bundle exec sidekiq -C config/sidekiq.yml -r ./config/boot.rb'
volumes:
- .:/myapp
depends_on:
- postgres
- redis
postgres:
image: postgres:9.5
environment:
POSTGRES_USER: my-postgres-user
POSTGRES_PASSWORD: my-postgres-pass
ports:
- '9001:5432'
volumes:
- 'postgres:/var/lib/postgresql/data'
redis:
image: redis
ports:
- '9002:6379'
volumes:
- 'redis:/var/lib/redis/data'
volumes:
redis:
postgres:
One key point to notice here is that I am exposing the containers services on non-standard ports (9000-9002).
If I start the setup with docker-compose up, the Redis and Postgres containers come up fine, but the containers for the web app and Sidekiq fail since they can't connect to Redis at redis:9002. Remarkably enough, the same setup works if I use 6379 (the standard Redis port) instead of 9002.
docker ps also looks fine afaik:
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
9148566c2509 redis "docker-entrypoint.sh" Less than a second ago Up About a minute 0.0.0.0:9002->6379/tcp rubydockerpadrino_redis_1
e6d47321c939 postgres:9.5 "/docker-entrypoint.s" Less than a second ago Up About a minute 0.0.0.0:9001->5432/tcp rubydockerpadrino_postgres_1
What's even more confusing: I can access the Redis container from the host via redis-cli -h localhost -p 9002 -n 0, but the web app and Sidekiq containers fail to establish a connection.
I am using this docker version on MacOS:
Docker version 1.12.3, build 6b644ec, experimental
Any ideas what I am doing wrong? I'd appreciate any hint how to get my setup running.
When you bind ports like this '9002:6379' you're telling Docker to forward traffic from localhost:9002 -> redis:6379. That's why this works from your host machine:
redis-cli -h localhost -p 9002 -n 0
However, when containers talk to each other, they are all connected to the same network by default (the Docker bridge or docker0). By default, containers can communicate with each other freely on this network, without needing any ports opened. Within this network, your redis container is listening for traffic on it's usual port (6379), host isn't involved at all. That's why your container to container communication works on 6379.