I´ve been trying to validade my microservices on a Docker structure, where i connect everything through linking containers but i´m not having success when trying to pass through an API Gateway with Zuul.
Basically i have theses microservices:
config-server
boutique-eureka-server
api-gateway
product-service
All of these start with success but i can´t acess the product-service behing the api-gateway.
My code is all at:
https://github.com/kalilmvp/myboutique/
along with the docker commands that i´ve used.
The error usually is:
com.netflix.zuul.exception.ZuulException: Forwarding error
In my later tests i´ve been also having this error:
Caused by: java.lang.RuntimeException: java.net.UnknownHostException: product-service
You can check it on the branch docker
Docker advises not to use --link option to link the containers and therefore this switch of docker run is deprecated.
There are many problems creating end-to-end links, like for example environment variables are being shared between 2 linked containers (imagine different values of JAVA_HOME for example).
Instead try coordinating your services using docker compose or define network using docker:
$ docker network create my-net
$ docker create --name my-eureka --network my-net --publish 8888:80 eureka:latest
...
$ docker network disconnect my-net my-eureka
Find more info in the docker docs
Related
I have one container of springboot application on docker,and one container of postgres with all the settings.How can I run both of them by linking them together.
The image springboot-postgresql corresponds to spring boot application,and postgres refers to postgresql.
Postgres is listening to 0.0.0.0,port 5432.
Please suggest,if there's another way other than making a .yml file and using docker compose up .
Thanks for the help.
The way you can communicate between each container is using docker network,
First, you need to create a network:
$ docker network create sprintapp
Above, the command creates a network named sprintapp
Then, you need to specify to a container to be inside the network:
$ docker run --name [CONTAINERNAME] --network sprintapp [IMAGE]
This way, all containers within the network could talk to each other, using [CONTAINERNAME] as the URI to locate it.
More info about this:
docker run reference
docker network reference
I have recently started exploring the microservice architecture using jhipster and was trying to install and run the jhipster-registry from docker hub. Docker shows that the registry is running, but I am unable to access it on port 8761.
Pulled the image with docker pull jhipster/jhipster-registry
Started the container with docker run --name jhipster-registry -d jhipster/jhipster-registry
Here's a snapshot of what docker container ls returns:
Am I missing something over here?
You are starting the JHipster Registry container, but you aren't exposing the port.
You can expose a port by passing the port flag -p 8761:8761 which will enable you to connect to it via localhost:8761 or 127.0.0.1:8761 in a browser.
You may need to configure some environment variables for the JHipster Registry to start correctly. These may depend on your generated app's options, such as authentication type. For convenience JHipster apps come with a docker-compose.yml file. You can start it with docker-compose -f src/main/docker/jhipster-registry.yml up, as documented.
I have a spring-config-sever project that I am trying to run via Docker. I can run it from the command line and my other services and browser successfully connect via:
http://localhost:8980/aservice/dev
However, if I run it via Docker, the call fails.
My config-server has a Dockerfile:
FROM openjdk:8-jdk-alpine
VOLUME /tmp
ARG JAR_FILE=build/libs/my-config-server-0.1.0.jar
ADD ${JAR_FILE} my-config-server-0.1.0.jar
EXPOSE 8980
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/my-config-server-0.1.0.jar"]
I build via:
docker build -t my-config-server .
I am running it via:
docker run my-config-server -p 8980:8980
And then I confirm it is running via
docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
1cecafdf99fe my-config-server "java -Djava.securit…" 14 seconds ago Up 13 seconds 8980/tcp suspicious_brahmagupta
When I run it via Docker, the browse fails with a "ERR_CONNECTION_REFUSED" and my calling services fails with:
Could not locate PropertySource: I/O error on GET request for
"http://localhost:8980/aservice/dev": Connection refused (Connection
refused);
Adding full answer based on comments.
First, you have to specify -p before image name.
docker run -p 8980:8980 my-config-server.
Second, just configuring localhost with host port won't make your my-service container to talk to other container. locahost in container is within itself(not host). You will need to use appropriate docker networking model so both containers can talk to each other.
If you are on Linux, the default is Bridge so you can configure my-config-server container ip docker inspect {containerIp-of-config-server} as your config server endpoint.
Example if your my-config-server ip is 172.17.0.2 then endpoint is - http://172.17.0.2:8980/
spring:
cloud:
config:
uri: http://172.17.0.2:8980
Just follow the docker documentation for little bit more understanding on how networking works.
https://docs.docker.com/network/network-tutorial-standalone/
https://docs.docker.com/v17.09/engine/userguide/networking/
If you want to spin up both containers using docker-compose, then you can link both containers using service name. Just follow Networking in Compose.
I could imagine that the application only listens on localhost, ie 127.0.0.1.
You might want to try setting the property server.address to 0.0.0.0.
Then port 8980 should also be available externally.
According to the docker documentation here
https://docs.docker.com/network/host/
The host networking driver only works on Linux hosts, and is not supported on Docker for Mac, Docker for Windows, or Docker EE for Windows Server.
On Mac what alternatives do people use?
My scenario
I want to run a docker container that'll host a micro-service
The micro-service has dependencies upon databases that I'm also running via docker
I thought I'd be able to use --net=host on Mac when running the micro-service
But the micro-service port is not exposed
I can override the db addresses (they default to localhost) on the microservice.
But that involves robust --env usage
What's the simplest / most elegant solution?
The most simple and most elegant solution is to use docker named bridge network.
You can create a custom bridge network (default is bridge) like this:
docker network create my-network
Every container deployed inside this network can communicate with each other by using the container name.
$ docker run --network=my-network --name my-app ...
$ docker run --network=my-network --name my-database...
In the example above you can connect to your database from inside your application by using my-database:port. If the container port is exposed in the Dockerfile you don't need to map it on your host and you can keep all your communication internal inside your custom docker bridge network.
In most cases the application its port is mapped (example: -p 80:80) so localhost:80 is mapped on container:80 and you can access the app from on your localhost. If the app needs to communicate with a db you don't need to expose the port of the db and you don't have to map it on localhost as explained already above.
Just keep the communication between app and db internal in your custom bridge network.
I have spring boot application which communicate with ElasticSearch 5.0.0 alpha 2.
My application successfully communicate with elastic and preform several queries.
When I try to dockerize my application, it fails to communicate with ElasticSearch, and I get the following error:
None of the configured nodes are available: [{#transport#-1}{127.0.0.1}{127.0.0.1:9300}]
I have spent a lot of time on the internet, but I have found problems when the ElasticSearch is dockerized, but in my case, the client is dockerized, and it is working fine without the docker.
The command I used to create the docker image is: docker build -t my-service .
The DockerFile is:
FROM java:8
VOLUME /tmp
ADD ./build/libs/myjarfile-2.0.0.jar app.jar
EXPOSE 8090
RUN sh -c 'touch /app.jar'
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]
To execute the image i use: docker run --name myname -d -p 8090:8090 -t my-service
Can someone share his/her experience with this issue?
Thanks
Guy Hudara
The problem is that your elasticsearch is not available on your dockerized host. When you put something in a docker container it also gets isolated on a network layer and localhost is localhost of the docker container but not the host itself. Therefore if you have elasticsearch also in a docker container use container linking and environment variable injection or reference your host machines address of your main network interface – not loopback – to your app.
Option 1
assuming that elasticsearch exposes 9200 try to run the following
$ docker run -d --name=elasticsearch elasticsearch
$ docker run -d --name=my-app --link elasticsearch:elasticsearch -p 8090:8090 my-app
Then you can define elasticsearch address in your app using env variable ${ELASTICSEARCH_PORT_9200_TCP_ADDR}.
Option 2
assuming your host machine runs on 192.168.1.10 you can also do the following:
$ docker run -d -p 9200:9200 elasticsearch
$ docker run -d -p 8090:8090 my-app
note that the name for the easticsearch container is optional here but the exposing of elasticsearch port mandatory. In this case you'll have to configure your elasticsearch host in your app given address of 192.168.1.10.