How to migrate to Docker?

https://docs.docker.com/storage/volumes/

Just move your data and then either create bind mounts to those directories or create a new volume in docker and copy the data to the volume path in your filesystem.

I also suggest looking into podman instead of docker. Its basically a drop in replacement for docker.

I'll try to answer the specific question here about importing data and sandboxing. You wouldn't have to sandbox, but it's a good idea. If we think of a Docker container as an "encapsulated version of the host", then let's say you have:

• Service A running on your cloud
• Requires apt-get install -y this that and the other to run
• Uses data in /data/my-stuff
• Service B running on your cloud
• Requires apt-get install -y other stuff to run
• Uses data in /data/my-other-stuff

In the cloud, the Service A data can be accessed by Service B, increasing the attack vector of a leak. In Docker, you could move all your data from the cloud to your server:

# On cloud
cd /
tar cvfz data.tgz data
# On local server
mkdir /local/server/
cd /local/server
tar xvfz /tmp/data.tgz ./
# Now you have /local/server/data as a copy

You're Dockerfile for Service A would be something like:

FROM ubuntu
RUN apt-get install -y this that and the other
RUN whatever to install Service A
CMD whatever to run

You're Dockerfile for Service B would be something like:

FROM ubuntu
RUN apt-get install -y other stuff
RUN whatever to install Service B
CMD whatever to run

This makes two unique "systems". Now, in your docker-compose.yml, you could have:

version : '3.8'

services:
  
  service-a:
    image: service-a
    volumes:
      - /local/server/data:/data

  service-b:
    image: service-b
    volumes:
      - /local/server/data:/data

This would make everything look just like the cloud since /local/server/data would be bind mounted to /data in both containers (services). The proper way would be to isolate:

version : '3.8'

services:
  
  service-a:
    image: service-a
    volumes:
      - /local/server/data/my-stuff:/data/my-stuff

  service-b:
    image: service-b
    volumes:
      - /local/server/data/my-other-stuff:/data/my-other-stuff

This way each service only has access to the data it needs.

I hand typed this, so forgive any errors, but hope it helps.

You can copy files into the docker image via a COPY in the dockerfile or you can mount a volume to share data from the host file system into the docker container at runtime.

Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:

Fewer Letters	More Letters
DNS	Domain Name Service/System
VPN	Virtual Private Network
k8s	Kubernetes container management package

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3 acronyms in this thread; the most compressed thread commented on today has 8 acronyms.

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