Docker run script in host on docker layout up

Question

Thank you for watching this question.

So my question is about best practices for running the script in the docker-compose up directive.

I am currently sharing volumes between the host and container so that script changes are displayed for both the host and the container. Similar to viewing a polling script for changes to a configuration file.

The script must act on the host when changes are made according to predefined rules.

So my question is:

How can I run this script in the docker-compose up directive or even from the docker file for this service, so that whenever the container goes up, the “observer” can detect any changes made and write.

The container in question will always work on the debian / ubuntu OS and should be architecture independent, that is, it should also work on ARM.

Thank you in advance

I would also like to know why the question was suppressed only because some people do not understand this.

I want to run the script on the host, not inside the container. I need the host to change its network interface configurations to easily adapt any environment. HOST needs to be changed. I repeat. It should be a user and easily edited on a web interface running inside CONTAINER to adapt to new environments.

I am currently doing this with a script running on a crontab based host. I just want to know the best practices and examples of how to run a script in a HOST from an INSIDE CONTAINER, so deployment can be simple for the installation operator to just run docker build.

thanks

Answer 1

I just want to learn the best practices and examples of how to run a script in a HOST from an INSIDE CONTAINER, so for the install statement it can be as simple as just running docker-compose up

It seems that there is no best practice that can be applied to your case. The workaround suggested here: How to run a shell script on a host from a docker container? - use the client/server trick.

• The host should start a small server (select the port and specify the type of request you should expect)
• The container, after its launch, should send this request to this server
• Then the host should run script / trigger the desired changes.

This can have serious security problems, so use them at your own risk.

Answer 2

The script should run continuously in the foreground.

In your Dockerfile, use the CMD directive and define the script as a parameter.

When using cli, use docker run -d IMAGE SCRIPT

Answer 3

You can create an alias for docker-compose up . Put something like this in ~/.bash_aliases (on Ubuntu):

 alias up="docker-compose up; ~/your_script.sh" 

I'm not sure if scripting on the host from the container is possible, but if possible, this is a serious security flaw. Containers must be insulated in order to use containers.