E.g., my local setup is to run a server (listens to :1111) and a docker container (with -p 5555:5555). The purpose is that a server can send the requests to docker container as well (to :5555).
I think that the typical way to deploy servers is to wrap it in a docker image and run the docker image in the cloud. How can I do the same thing but run my custom docker container inside of a server automatically (e.g., add docker run command to a Dockerfile)?
Related
I am reading a docker run command where it maps /var/run/docker.sock
like:
docker run -it --net=host --rm -v /var/run/docker.sock:/var/run/docker.sock theimage /bin/bash
Why would the container would need access to the socket? (this article says it is a very bad idea.)
What would be one case where the container need access to the socket?
It is not necessary until the container needs to invoke itself the docker daemon, for example, in order to create and run an inner container.
For example, in my CI chain Jenkins builds a docker image to run the build and test process. Inside it we need to create an image to test and then submit it to K8S. In such situation Jenkins, when builds the pipeline container, passes to it the docker socket to allow the container to create other containers using the host server docker daemon.
I have docker on my host machine with a container running. I was wondering if it's possible, and what the best approach would be, to "trigger" a container creation from the running container.
Let's say my machine is host and I have a container called app (with id 123456789) running on host.
root#host $ docker contain ls
123456789 app_mage .... app
I would like to create a container on host from within app
root#123456789 $ docker run --name app2 ...
root#host docker container ls
123456789 app_mage .... app
12345678A app_mage .... app2
What I need is for my app to be running on docker and to run arbitrary applications in an isolated environment (but I'd rather avoid docker-in-docker)
A majority of the Docker community will veer away from these types of designs, however it is very doable.
Similar to Starting and stopping docker container from other container you can simply mount the docker.sock file from the host machine into the container, giving it privilege to access the docker daemon.
To make things more automated, you could use the docker-py sdk to start containers from inside a container, which would in turn access the Docker deamon on the host machine hosting the container that you are spawning more containers from.
For example:
docker run -v /var/run/docker.sock:/var/run/docker.sock image1 --name test1
----
import docker
def create_container():
docker.from_env().containers.run("image2", name="test2")
This example starts container test1, and runs that method inside the newly created container, which in turn creates a new container test2 running on the same host as test1.
I am creating a Spring Boot monitoring agent that collects docker metrics. The agent can be attached through POM dependency to any client Spring Boot application that runs inside a docker container.
In the agent, I am trying to programatically run docker stats
But, it fails to execute because the docker container doesn't have docker client installed in it.
So how can I run docker commands in docker container? Please note, I can't make changes to the Dockerfile of client.
You may execute docker commands within the container by defining the docker socket in the container.
run the container and mount the 'docker.sock' in the following manner:
docker run -v /var/run/docker.sock:/var/run/docker.sock ...
so mainly you have to mount docker.sock to order to run docker commands within container.
how to access a path of a container from docker-machine? I have the ip docker-machine and I want to connect via remote in a docker image, e.g:
when I connect to ssh docker#5.5.5.5, all file are docker-machine, but I wat to conect a docker image via ssh.
whe I use this comman docker exec -u 0 -it test bash all files from the imagen are ok, but I want to access with ssh using docker-machine.
How can I do it?
This is tricky as Docker is designed to run a single process in foreground and containers dies when the process completed. This means Docker containers don't run anything additional other than what you define in the Dockerfile or docker-compose.yml.
What you can try is using docker-compose.yml file, expose the port 22 to outside world (also can be done through command line with Dockerfile). This is NOT guaranteed to work as this require the image to run an SSH daemon and most cases it runs one process.
If you're looking to persist files that are used by containers, such as when a container is re-deployed it starts where it left off, you can mount a folder from host machine to the container as a volume.
So far, I have always copied files from the docker container to my VM first (web host), and later, run scp command line from my local machine to download it from the VM. Similar scenario happening for uploading files/folders. Is there a direct way to do that using scp?
In order to directly copy from your container you need sshd installed on the container and expose an port for ssh to public when you run the container.
Take in count that if you do you have to make sure that ssh is properly configured and secured.
Example:
*We take in count that you already have ssh configured on the container
docker run -d -p 8000:22 --name docker image
scp -P 8000 username#myserver.com:/root/file.txt ~/file.txt