External access to Node.JS app, within Docker container - node.js

i have a Node app running within a Docker container, hosted on Elastic Beanstalk (single instance). The docker has port 3000 exposed to access the app within the docker, and I can 'curl 172.17.0.32:3000/test' from the host which returns the expected response.
The problem I have is accessing this port externally using the elastic beanstalk url. i.e
http://XXXXXX-env.elasticbeanstalk.com:3000/test
This will time out.. can anyone recommend how to gain access to this port externally?
thanks

Check this for reference
http://victorlin.me/posts/2014/11/26/running-docker-with-aws-elastic-beanstalk
see what your docker ps command returns.
The ip you have shared looks like private ip address of the docker service used for internal network. You have to enable a bridge between your host and docker container by supplying -p 3000:3000 to the run command and finally enable the app in your elastic console.

Related

Unable to communicate between docker and external service

I have a docker container running in localhost:3000
Also, I have a node app running in localhost:8081
Now if I want to make post or get request from localhost:3000 to localhost:8001 its not working at all.
Now if run the service as a binary (not a docker file) on localhost:3000 the same API requests works.
How do I communicate if using docker?
Each container runs on it's own bridge network where localhost means the container itself.
To access the host, you can add the option --add-host=host.docker.internal:host-gateway to the docker run command. Then you can access the host using the host name host.docker.internal. I.e. if you have a REST service on the host, your URL would look something like http://host.docker.internal:8081/my/service/endpoint.
The name host.docker.internal is the common name to use for the host, but you can use any name you like.
You need docker version 20.10 for this to work.

Docker cannot access mariadb server

I am newbie on docker.
I want to migrate my nodejs app to docker, and existing database already installed on server (172.17.2.1). I set mariadb host 172.17.2.1 on my nodejs config.
After that, I created an images and run with :
docker run -p 3009:3009 -d my-node
actually its already running, but when I tested to open by browser, I got an error that my app cannot connect to 172.17.2.1 (connecting to database).
I try to create bridge IP (172.17.2.135) and make a same subnet, but still got a same error.
My images on docker inside doesn't know 172.17.2.1 on my LAN.
Please help me,
I use windows 10 environment
You have two options to allow your container to reach an external server:
Run your docker container on your host network:
docker run -p 3009:3009 --network host -d my-node
This way your container will be able to reach anything reachable from your machine
create a network bridge: in this case docker will route the traffic from the container to the external server. the bridge IP can't be your docker machine IP as you tried to do.

Two docker container (nginx and a web app) not working together (linux)

I built both containers using a Dockerfile (for each). I have the NGINX container pointing (proxy_pass http://localhost:8080) to the port that the web app is exposed (via -p 8080:80). I am able to get it to work when I just install NGINX in the linux machine, but when I use a dockerized NGINX, I just get the default NGINX index.html. Do I have to build both containers using Docker-Compose.yml file (as oppose to Dockerfile) when I want the containers working together? Sorry, if I didn't put any code, but at this point, I'm just wanting to know if I'm taking the correct approach (using Dockerfile or Docker-Compose).
The Nginx proxy needs access to the host (!) network for this to work, e.g.:
docker container run ... --net=host ... nginx
Without it, localhost refers to the proxy (localhost) which likely has nothing on :8080 and certainly not your web app.
Alternatively, if the proxy's container (!), can resolve|access the host then processes in the container can refer to host-accessible ports using the host's DNS name or IP.
Docker Compose (conventionally) solves this by putting the containers onto a new virtual network. The difference then would be that, rather than mapping everything onto host ports, each container (called a service) gets a unique name and a container called proxy could refer to a container called web on port 8080 as http://web:8080.
You may achieve similar results with Docker only by creating a network and then running containers on it, e.g:
docker network create ${NETWORK}
docker container run ... --net=${NETWORK} --name=proxy ...
...

Exposing node Server running on docker doesn't work

I am running a angular app on node server and in server.js I have specified app.listen(8084,localhost)..So when i run npm start in the docker container and try to -p 8084:8084 in docker run I was not able to get anything, even though the curl command inside my container curl localhost:8084 was giving me right result.
So i change the app.listen(8084) and the -p 8084:8084 started working..I am not sure why ?
When you open socket, you need to bind it to some interface in your system. There are predefined values:
0.0.0.0 - all interfaces, your service will be available from any interface
locahost, 127.0.0.1 - bind locally. That means service is NOT available from oustide -- this is your case.
You also can specify particular interface IP address to bind to it.
When you start your container, by default docker start default bridge network, so your container is being put into separate network and to access it, you need to allow incoming remote connections in container.
You bind your service to localhost into a container, so no communication is possible outside the container. localhost for your node server is not the same than localhost for your container.

Send request from one docker container to another

I'm trying to move some existing servers to be housed within docker containers. I have two: an app server and an api server but developed with node.js. I have them both working within an ubuntu vm and can hit both apps from outside the vm which is great.
Each server has it's own domain. The app server uses the domain app and the api server uses the api domain, clever I know. Locally I added both domains to my hosts file to point to the ip assigned to the ubuntu vm.
The only issue I'm having is there is a request sent from the app server that needs to be routed to the api server. Tried editing the hosts file of both the app server container (via the Dockerfile) and the ubuntu vm however the request fails.
Is there a simple way to get that request to not go out and try to resolve the api domain but get it to point to the api container?
A typical solution to this would be to use Docker's --link option to link the containers. That is, if you do:
docker run -d --name api myapi
docker run -d --name app --link api:api myapp
Then within the app container, the hostname api will map to the api container. You will also have a set of environment variables available that describe the exposed ports on the linked container. E.g., if your "api" container exposed port 80, the variable would look like:
API_PORT_80_TCP=tcp://172.17.0.10:80
API_PORT_80_TCP_PORT=80
API_PORT_80_TCP_PROTO=tcp
API_PORT=tcp://172.17.0.10:80
API_NAME=/app/api
API_PORT_80_TCP_ADDR=172.17.0.10
There are some disadvantages to the link option:
This only works for containers hosted on the same physical host
If you restart the "api" container, you have to restart the "app" container, too.
Both of these particular problems can probably be resolved by the orchestration tool of your choice if you are operating in a multi-host environment.
The linking feature (--link) is a legacy feature.
You should always prefer using Docker network drivers over linking.
Example: running a Redis container with Redis binding to localhost then running the redis-cli command and connecting to the Redis server over the localhost interface.
$ docker run -d --name redis example/redis --bind 127.0.0.1
$ # use the redis container's network stack to access localhost
$ docker run --rm -it --network container:redis example/redis-cli -h 127.0.0.1
See the docs for details.
https://docs.docker.com/compose/link-env-deprecated/
https://docs.docker.com/engine/reference/run/#network-settings

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