@veronikya said in mongodb replica set:

The host’s local dns resolution is not configured. The problem of the host’s hosts being unable to be resolved in docker has been solved. Surprisingly
Solution:
Edit the /etc/resovel.conf file
Add 127.0.0.53

One immediate issue I can think of here is that editing resolv.conf directly is no longer supported and not recommended (because the changes do not survive a reboot) - unless you install the resolvconf package?

@phenomlab
Sorry to delay in responding, yes as i mentioned above, i had to remove my redis from docker and reinstall a new image with this command

docker run --name=redis -p 127.0.0.1:6379:6379 -d -t redis:alpine

and now when i test my ip and port on
https://www.yougetsignal.com/tools/open-ports/

the status of my redis port is closed. I think which to configure firewall in droplet digital ocean is a good idea too, and i will configure soon.
Thanks for the help!

@Hari sort of, but not in the sense of a full blown system

In simple terms, Docker is a software platform that simplifies the process of building, running, managing and distributing applications. It does this by virtualizing the operating system of the computer on which it is installed and running.