I have 2 hosts with Docker: Ubuntu and Windows(docker-desktop). I want to connect a container with Adminer(Windows) to a container with MariaDB(Ubuntu). Is it possible?
My hosts locate in the same local network, and containers are isolated from each other(of course). I was trying to create overlay network and to bind between each other, but worker's message has been: "docker: Error response from daemon: attaching to network failed, make sure your network options are correct and check manager logs: context deadline exceeded." My goal is to make communication between different host containers. Please, can you help me with my problem :)
Important: Make sure your host machines can communicate with each other over the network, and there are no issues due to network firewalls, etc.
Looks like need to bind the port of your container to your host machine.
When you are running your Docker containers use the -p option. You can find a lot of examples at https://docs.docker.com/config/containers/container-networking/.
After you have exposed your containers port, you can access them using <host-machine-ip>:<host-machine-port-you-used-to-bind-container>
Related
Question:
How can I access specific containers inside a docker swarm network from outside the network?
I don't need to access arbitrary ports, the exposed container ports are fine, but I need to be able to connect to a specific container, not just any container I am routed to via load balancing.
As in, I can currently do:
curl localhost:8582/service_id
And get something like:
1589697532253.0.8570331623512102
But the result varies, because it is load balanced to a different container each time I make the request. I only need this for debugging, I usually want the load balancing behavior, but when there is an issue with a specific container it is essential that I make requests only to that container.
I can do it within a container inside the network, but it is a lot easier to debug from my local machine, instead of inside a container.
Environment:
I am not sure if it is relevant, but I am on windows, running docker desktop, engine v19.03.8.
Things I tried:
I tried tunneling into the docker network with wireguard, however I believe that is a non-starter because my host OS is windows, and I can't find any wireguard images that support non-linux host OSes (and I'm not sure that is even technically possible).
When I run docker network inspect ingress -v I can see there appears to be IPs associated with each container (10.0.0.12, 10.0.0.13) which differ from the IPs on the overlay network (10.0.18.7, 10.0.18.8), but when I try to access my exposed port over any of those IPs, the connection attempt is ignored and does not connect.
I tried adding a specific network route to make sure the packets were going to docker, by forcing all packets in the /24 address range to go through the docker gateway, but that didn't work either (route add -p 10.0.0.0 MASK 255.255.255.0 192.168.8.177 METRIC 1 IF 49).
Any suggestions would be greatly appreciated!
It's been several days now trying to create a redis cluster with docker-compose, but it doesn't work because redis doesn't send a good ip address when my client sends a request (it sends to my host internal ip from docker, but i want he send host ip).
I'm looking for "cluster-announce-ip" but no success.
I've tried to create with host mode but it doesn't work ... I don't understand why..
Now redis-cli shows:
Waiting for the cluster to join
You could find my work here: https://github.com/fhebuterne/redis-cluster
If someone has a solution, I'm interested
Thanks
After some tests, it not possible to use internal network in docker with multiple docker container and redis cluster (even with "cluster-announce-ip"), so the only solution i has found, is to define on each service (on docker compose), this option :
network_mode: "host"
And using the brige docker ip between host and containers, on windows i found it with ipconfig and look for "vEthernet (DockerNAT)", base ip is 10.0.75.1, on my redis-cli and redis.conf, i put 10.0.75.2, so each containers can be connected with others and cluster send good response when i send request with my host computer, i'm sorry if is not clear, i has push my solution on my repository (the link is on my previous message).
How do you access remote Docker container by its hostname?
I need to access remote Docker containers by its hostnames (or some constant IP's) for development and testing purposes. I have tried:
looking for any DNS approach (have not found any clues),
importing /ets/hosts (probably impossible),
creating tunnes (only this works but it is very time consuming).
It's the same as running any other process on a host, Docker or not Docker: you access it via the host name or IP address of the host and the port the service is listening on (the first port of the docker run -p argument). Docker containers don't have externally visible individual IP addresses any more than non-Docker HTTP or ssh daemons do.
If you do have DNS infrastructure available to you, you could set up CNAME records to resolve particular service names to the specific hosts that are running them.
One solution that may help you is some sort of service registry; in the past I've used Consul with some success. You can configure Consul with some health checks or other probes ("look for an HTTP service on port 12345 that answers GET / calls"), and it will provide its own DNS service ("okay, http://whatevername.service.consul:12345/ will reach your service on whichever hosts it happens to be running on").
Nothing in the Docker infrastructure specifically helps this. Using /etc/hosts is distinctly not a best practice: the name-to-IP mapping needs to be kept in sync across all machines and you'll start wishing you had a network service to publish it for you, which is exactly what DNS is for.
I am setting up a simple cluster using docker on several hosts. Before using docker the processes were simply started with a argument giving the address to a config server. The first thing each process does is to connect to the config server, get the addresses (host and port) of all the other services as well as register itself with host (and several different ports, one for each the services it provides).
However, it does not seem to be possible to dockerize this workflow? Since a process in a container seems not to be able to get the address and ports on the host (based on for example How to get the IP address of the docker host from inside a docker container) it does not know what to register itself as. Is this really not possible?
If not, are there any alternative ways this sort of setup is intended to be run using docker?
An application server is running as one Docker container and database running in another container. IP address of the database server is obtained as:
sudo docker inspect -f '{{ .NetworkSettings.IPAddress }}' db
Setting up JDBC resource in the application server to point to the database gives "java.net.ConnectException".
Linking containers is not an option since that only works on the same host.
How do I ensure that IP address of the database container is visible to the application server container?
If you want private networking between docker containers on remote hosts you can use weave to setup an overlay network between docker containers. If you don't need a private network just expose the ports using the -p switch and configure the addresses of the host machine as the destination IP in the required docker container.
One simple way to solve this would be using Weave. It allows you to create many application-specific networks that can span multiple hosts as well as datacenters. It also has a very neat DNS-based service discovery mechanism.
I should disclaim, I am one of Weave engineering team.
Linking containers is not an option since that only works on the same host.
So are you saying your application is a container running on docker server 1 and your db is a container on docker server 2? If so, you treat it like ordinary remote hosts. Your DB port needs to be exposed on docker server 2 and that IP:port needs to be configured into your application server, typically via environment variables.
The per host docker subnetwork is a Private Network. It's perhaps possible to have this address be routable, but it would be much pain. And it's further complicated because container IP's are not static.
What you need to do is publish the ports/services up to the host (via PORT in dockerfile and -p in your docker run) Then you just do host->host. You can resolve hosts by IP, Environment Variables, or good old DNS.
Few things were missing that were not allowing the cross-container communication:
WildFly was not bound to 0.0.0.0 and thus was only accepting requests on eht0. This was fixed using "-b 0.0.0.0".
Firewall was not allowing the containers to communication. This was removed using "systemctl stop firewall; systemctl disable firewall"
Virtual Box image required a Host-only adapter
After this, the containers are able to communicate. Complete details are available at:
http://blog.arungupta.me/2014/12/wildfly-javaee7-mysql-link-two-docker-container-techtip65/