I need realize connection from one docker container to another.
docker run -ti is not the solution, I need certainly ssh access.
How to implement this communication type?
Can you help?
docs.docker.com/examples/running_ssh_service –from Wolfgang Fahl
Related
I know k3d can do this magically via k3d cluster create myname --token MYTOKEN --agents 1, but I am trying to figure out how to do the most simple version of that 'manually'. I want to create a server something like:
docker run -e K3S_TOKEN=MYTOKEN rancher/k3s:latest server
And connect an agent something like like:
docker run -e K3S_TOKEN=MYTOKEN -e K3S_URL=https://localhost:6443 rancher/k3s:latest agent
Does anyone know what ports need to be forwarded here? How can I set this up? Nearly everything I try, the agent complains about port 6444 already in use, even if I disable as much as possible about the server with any combination of --no-deploy servicelb --disable-agent --no-deploy traefik
Feel free to disable literally everything other than the server and the agent, I'm trying to make this ultra ultra simple, but just butting my head against a wall at the moment. Thanks!
The containers must "see" each other. Docker isolates the networks by default, so "localhost" in your agent container is the agent container itself.
Possible solutions:
Run both containers without network isolation using --net=host, map API port of the server to the host with --port and use the host IP in the agent container or use docker-compose.
A working example for docker-compose is described here: https://www.trion.de/news/2019/08/28/kubernetes-in-docker-mit-k3s.html
I have two container, one is a container for node.js code and another for a mongodb database. I set the network_mode to host for both containers, there are certain network restrictions making me have to do this. Additionally, both container are on the same physical mac machine. If I want to connect to the mongodb database from the node.js container, what should my connection string look like. I know that if I used a bridged network, I would use the name of the mongo container for the host name. However, in this case I have tried localhost, 0.0.0.0, 127.0.0.1, etc. none of which are working. How would I access the mongdb database in this case?
easiest way to use docker inspect and find the IP of the docker container and login/connect to it. Alternatively you can use VS Code (https://code.visualstudio.com/download) and install docker plugin
find running docker containers and container ids
docker ps
get details of the docker specific docker container
docker inspect <CONTAINER ID> | grep "IPAddress"
example
"SecondaryIPAddresses": null,
"IPAddress": "172.17.0.2",
"IPAddress": "172.17.0.2",
VS Code docker plugin
According to this github issue, network_mode doesn't work on Docker for Mac.
The comment on the issue I linked did say that if you need to access a service on the host from a container, you can use host.docker.internal, but this might not be relevant to your use case.
What is best practice to access the host's services within a docker container?
I'd like to access PostgreSQL running on the host within my application which runs in a docker container.
The easiest approach I've found is to use docker container run --net="host" which, based on this answer, behaves as follows:
Such a container will share the network stack with the docker host and from the container point of view, localhost (or 127.0.0.1) will refer to the docker host.
Be aware that any port opened in your docker container would be opened on the docker host. And this without requiring the -p or -P docker run option.
Which does not seem to be best practice since the containers should be isolated from the host.
Other approaches I've found are awking the hosts IP. May this be the way to go?
The best option in this case to treat the host as a remote machine. That way the container will be portable and would not have a strict dependency on network locations when connecting to the database.
In addition to what is mentioned on the drawbacks of using --network=host, this option will tightly couple the container to the host by assuming that the database is found on localhost.
The way to treat the machine as a remote one, is to use standard network constructs such as IP and DNS. Define a new DNS entry for the container that will point to the host where the DB is found using the
--add-host option to docker run.
docker run --add-host db-static:<ip-address-of-host> ...
Then inside the container you connect to the database via db-static
The Eclipse Remote Systems view is a great tool to connect to VMs and explore their file systems, currently the following options are available:
First I find out the container IP by running this command:
docker inspect <container> | grep IPAddress | cut -d '"' -f 4
Once I have the IP, I launch the New Connection wizard from the Remote Systems view, I tried to select Linux, SSH only and FTP only and in the Hostname field I paste the container IP, click Finish and the connection seems to be successfully created, now when I try to expand the the Files node it prompts for User and Password, the problem is that I don't have that info, does the user/pass vary from container to container? how can I get this info?
You can just instantiate a container with that image but with a shell so that you can see what usernames are configured on that image.
docker run -it node /bin/bash
You can then configure users, password and do a:
docker commit <image-name> my-node:0.1
Then you can instantiate a new container:
docker run -d -p 80:9080 -p 443:9443 my-node
Is ssh also running in that container? If not you will have to install it into the container so that you can ssh to it.
A docker container only runs a single parent process at a time (on your host machine that parent process is 'init' which runs a bunch of system services). In the case of your node container, that parent process is a node server.
Eclipse connects to a remote machine by connecting to a listener on that machine using some protocol. SSH of FTP, for example. With the docker container, there is no process listening for this connection, so you cannot connect using Eclipse as it is. You have two options...
Use the command line and docker exec to connect to the machine and explore its filesystem. No pretty pictures, but you don't need a lot of knowledge.
Modify your container in some way to connect to it. you have two options here...
A. Modify your image to run an SSH daemon. A simple way to do that is to use the phusion/baseimage container as your parent, and have it spawn both the ssh daemon and the node server. You need to know a good amount about linux sysadmin to get this working (not a lot, but a good amount).
B. Launch a second copy of the container with a different command, such as ssh -d. You can then connect to the second copy. This has the downside that it won't be the same container you're interested in, and you STILL have to modify the image since I doubt the node image even has an ssh daemon installed... but it is less knowledge than wrapping your head around runit.
I am trying to deploy a Scala based application to dokku, the application runs a http server and a customised sshd server.
The problem I have is it seems that dokku only supports one port for the application.
I need dokku to expose both my applications ports to the web.
In docker this is possible and quite straight forward to do, but when I implement the same technique in the dokku file, I get an error.
Any suggestions on allowing two ports to be accessible?
Since this is, after all, docker, you can use an ambassador...
You will need a line like:
docker run -t -i -link mysql:mysql -name mysql_ambassador -p 3306:3306 ctlc/ambassador
Replacing with your port and mysql with your container name (from docker images)
See https://www.ctl.io/developers/blog/post/deploying-multi-server-docker-apps-with-ambassadors
NOTE: Make sure you docker pull svendowideit/ambassador:latest before...