I have several containers running in a stack controlled by docker-compose.
Amongst these is one running node-red.
The node-red container needs to be able to search the network for a device that is on the hosts network (192.168.1.0/24).
With the default networking the containers can ping and connect to the host network when they know the IP, unfortunately the node-red implementation only scans the local networks, and it only has the docker bridge network (172...) so it only searches there.
I've tried multiple combinations of the docker network setups to try and get the containers to see the 192 network as local. When I am able to get a 192 network address, the containers can not ping other hosts on the external (to the host machine) network.
TLDR: Docker container needs to be able to see other docker containers and also have an IP address on the hosts network and be able to connect to other services on the hosts network.
Okay, I found a solution that works for me:
In the docker-compose.yml
app:
image: youimage
network_mode: "host"
adding the network_mode: "host" was what I needed
Related
I have set up multiple containers in one docker compose file.
I want all containers to share a network. One container needs network_mode: host.
As I understand, adding network_mode: host to one container prevents this container from accessing the other containers which does not have network mode host.
So I tried to define two networks, one with driver bridge (network A) (all containers should be connected to this network) and one with driver macvlan (network B) (only the container that requires network_mode: host should be connected to this network).
In general, everything works as expected. The container which is connected to network B got an ip addres in my local network and can communicate with the other containers connected to network A.
The problem is, that the ports configuration seems to not work. I want to expose a port of the container connected to network A and B to all connected host networks. This doesn't work when I connect the container to network A and B.
Thank you!
I am learning docker network. I created a simple docker-compose file that starts two tomcat containers:
version: '3'
services:
tomcat-server-1:
container_name: tomcat-server-1
image: .../apache-tomcat-10.0:1.0
ports:
- "8001:8080"
tomcat-server-2:
container_name: tomcat-server-2
image: .../apache-tomcat-10.0:1.0
After I start the containers with docker-compose up I can see that tomcat-server-1 responses on http://localhost:8001. At the first glance, the tomcat-server-2 is not available from localhost. That great, this is what I need.
When I inspect the two running containers I can see that they use the following internal IPs:
tomcat-server-1: 172.18.0.2
tomcat-server-2: 172.18.0.3
I see that the tomcat-server-1 is available from the host machine via http://172.18.0.2:8080 as well.
Then the following surprised me:
The tomcat-server-2 is also available from the host machine vie http://172.18.0.3:8080 despite port mapping is not defined for this container in the docker-compose.yml file.
What I would like to reach is the following:
The two tomcat servers must see each other in the internal docker network via hostnames.
Tomcat must be available from the host machine ONLY if the port mapping is defined in the docker-compose file, eg.: "8001:8080".
If no port mapping definition then the container could NOT be unavailable. Either from localhost or its internal IP, eg.: 172.18.0.3.
I have tried to use different network configurations like the bridge, none, and host mode. No success.
Of course, the host mode can not work because both tomcat containers use internally the same port 8080. So if I am correct then only bridge or none mode that I can consider.
Is that possible to configure the docker network this way?
That would be great to solve this via only the docker-compose file without any external docker, iptable, etc. manipulation.
Without additional firewalling setup, you can't prevent a Linux-native host from reaching the container-private IP addresses.
That having been said, the container-private IP addresses are extremely limited. You can't reach them from other hosts. If Docker is running in a Linux VM (as the Docker Desktop application provides on MacOS or Windows) then the host outside the VM can't reach them either. In most cases I would recommend against looking up the container-private IP addresses up at all since they're not especially useful.
I wouldn't worry about this case too much. If your security requirements need you to prevent non-Docker host processes from contacting the containers, then you probably also have pretty strict controls over what's actually running on the host and who can log in; you shouldn't have unexpected host processes that might be trying to connect to the containers.
My program is consisting of a network of ROS1 and ROS2 nodes, which are software that work with a publish/subscribe way of communication.
Assume there is 4 nodes running inside a custom network: onboard_network.
Those 4 nodes (ROS1) can only communicate together, therefore we have a bridge node (ROS1 & ROS2) that needs to be sitting on the edge on both onboard_network and host network. The reason why we need the host network is because the host is inside a VPN (Zerotier). Inside the VPN we have also our server (ROS2).
We also need the bride node to work with host network because ROS2 work with some multicast stuff that works only on host mode.
So basically, I want a docker compose file running 4 containers inside an onboard_network & a container running inside the host network. The last container needs to be seen from the containers in the onboard_network and being able to see them too. How could I do it ? Is it even possible ?
If you're running a container on the host network, its network setup is identical to a non-container process running on the host.
A container can't be set to use both host networking and Docker networking.
That means, for your network_mode: host container, it can call other containers using localhost as a hostname and their published ports: (because its network is the host's network). For your bridge-network containers, they can call the host-network container using the special hostname host.docker.internal on MacOS or Windows hosts, or on Linux they need to find some reachable IP address (this is discussed further in From inside of a Docker container, how do I connect to the localhost of the machine?.
How can I access the hosts network with a docker container? Can I put a container in the hosts network with another IP from the hosts network?
Current situation:
Docker container (default bridge network): 172.17.0.2/16
Host (server): 10.0.0.2/24
Question:
Can I put the docker container on the 10.0.0.0/24 network as a secondary address?
(or) Can I access the hosts network on the container and vica versa?
Reason:
I want to access the hosts network from my container (for example: monitoring server).
I want the container to act as a server accessible from the hosts network on all ports.
Note:
I run several docker containers so a few ports are already forwarded from the host and these should remain so. So an all-port-forward from the hosts IP isn't really a solution here.
Setup on host:
basic docker system
Centos 7
Macvlan networks may be the solution you are looking for.
You could assign multiple MAC/IP addresses on virtual NICs over single physical NIC.
There are some prerequisites for using Macvlan.
I have several services specified inside a docker compose file that are communication with each other via links. Now I want one of these services to talk to the outside world and fetch some data from another server in the host network. But the docker service uses its internally assigned IP address which leads to the firewall of the host network blocking his requests. How can I tell this docker service to use the IP address of the host instead?
EDIT:
I got a step further, what I'm looking for is the network_mode option with the value host. But the Problem is that network_mode: "host" cannot be mixed with links. So i guess i have to change the configuration of all the docker services to not use links. I will try how this works out.
You should open a port like to that service
ports:
8000:8000
The 8000 on the left is the host port and the 8000 on the right will be the IP port