What kind of configuration for docker do I need to read data from host's ethernet port inside a container? On the host machine (Ubuntu 20.04.4), I go to network -> Wired -> IPv4 Method, select Manual and set the static address and netmask from where I can receive the data via a socket. When running the code inside a docker container that is on the default network (so no configuration related to networking at all), I don't receive any data.
The solution was to publish my port with UDP, like so:
ports:
- "50000:50000/udp"
Related
Here is my situation：
First，I run a MySQL container(IP:172.17.0.2) on centOS;
Then I run a Nacos contanier with specified datasource(MySQL above) on the same host, but i didn't use the ip of the MySQL container, instead I used the ip of the bridge Gateway(172.17.0.1)(two containers both link to the default bridge).
What surprised me was that Nacos works well, it can query config data from MySQL container normally.
How did this happen? I have read some documention but didn't get the answer.It really confused me.
On modern Docker installations, try to avoid using the default bridge network. docker network create a network (it doesn't need any special options, but it does need to be created) and then launch your containers on --net that network. If you're using Compose, it creates a ("user bridge") network named default for you.
On your CentOS host, if you run ifconfig, you should see a docker0 interface with the 172.17.0.1 address. When you launch a container with the docker run -p option, that container is accessible via the first port number on all host interfaces, including the docker0 interface.
Meanwhile, inside a container (on the default bridge network), it sees that same IP address as the normal IPv4 gateway address (try docker run --rm busybox route -n). So, when you connect to 172.17.0.1:3306, you're connecting out to the host, and then connecting to the published port of the database container.
This isn't a totally standard way to connect between containers, though it will work. You should prefer using Docker named networks, which will let you connect to another container using the container's name without manually doing any IP-address lookups. If you really can't move off of the default bridge network, then the standard approach is to --link to the other container, but this entire path is considered outdated.
I'm trying to set up an HTTP server in a Docker container on port 8888 on a Raspbian host. I use -p 8888:8888 to bind the port to all interfaces. This allows me to connect to it with localhost:8888 without issue. However, when I connect to the bound port on the host from another device in the same NAT using its IP address (192.168.1.xxx), my connection is refused.
I'm using the bridge networking mode for this. I tried the "host" mode and that didn't work at all.
You need to link the containers with the (deprecated) —-link command documented here. Otherwise they run in isolated networks. You can also use the more modern and supported way and create a network that each shares; both are described in the linked page.
I deployed a demo web API project on port 8086.I am able to run it on my local browser using localhost:8086/api/controllername and also using local machine IP address for example: 192.0.0.0:8086/api/controllername. I tried accessing the URL from another machine on same LAN and I am able to access it.
But now I want to access it from machines on other networks (publicly).
How can I assign a static IP so that I can use the API from any machine irrespective of network? I created a network using below commands
docker network create --driver bridge --subnet 172.18.0.0/16 -- gateway=172.18.0.1 IPStatic
and
docker network connect --ip 172.18.0.2 IPStatic Containerid.
But unable to access the api using 172.18.0.2:8086/api. Am I missing something? I am using asp.net core web api and I am fairly new to Docker.
You always use the host IP address for this, the same way as if you were running the service outside of Docker. The container-private IP addresses are unreachable from other hosts (and on some platforms aren't even reachable from outside Docker on the same host); it's usually wrong to manually set them or to try to look them up.
If it's specifically important that this service have its own IP address, you need to ask your network administrator to assign an additional address to the host. The docker run -p option can bind a service to only specific network interfaces or addresses. On a Linux host I might run
# Assign the alias address
ifconfig eth0:0 192.0.0.2
# Run the service bound to only this interface
docker run -p 192.0.0.2:80:8080 ...
You might need to reconfigure other services to not listen on this new interface. For Docker services you'd use the same docker run -p option to bind to only the host's primary interface and to localhost (127.0.0.1); configuration for non-Docker services is specific to the service.
I am using Docker 18.06.1-ce-win73 on windows 10 and trying to perform the following udp operation:
Docker port 10001 --------------> host port 10620
It is mandatory for the application running on the host to receive packets from the port 10001.
Inside the docker container, using python I bind on the IP ('0.0.0.0', 10001) and use the socket to send my packets to the host IP on port 16020.
I have also started the container with the argument -p 10001:10001/udp.
Unfortunately, when receiving the packet on the Host application, the origin port is not 10001 but a random one.
Is it possible to force docker to use a specific source port when using UDP from inside the container ?
You can control the container source port, but when you communicate outside of docker, even to your host, the request will go through a NAT layer that will change the source to be the host with a random port. You may be able to modify the iptables rules to work around this NAT effect.
However, if you really need control of the source port like this, you may be better off switching to host networking (--net=host or network_mode: host depending on how you run your containers), or change to a networking driver like macvlan that exposes the container directly without going through the NAT rules.
I'm having a few docker containers (Using docker-compose and a single network - network-sol)
One of the containers is a Spring Boot application that sends UDP broadcast to the local network. 255.255.255.255 fails because It's the local broadcast address of network-sol
How can I broadcast UDP messages such as the "top local network" Will get those packets? Do i have to use directed broadcast address for that?
P.S
broadcast works if the application is deployed outside of docker (part of the local network
You should either run the service defined in your docker-compose.yml file with network_mode: host.
Alternatively you can publish the port of the container you intended to communicate with by publishing it using the following configuration. Note that the /udp is required for UDP communication to work.
service:
ports:
- "8080:8080/udp"
I have gotten some luck out of this. The guide specifies sysctl parameters that are needed for broadcast forwarding from a docker network, you should then be able to either use his script or specify these parameters when running docker.