I have docker container and execute command
# rm -rf /etc/
rm: cannot remove '/etc/hosts': Device or resource busy
rm: cannot remove '/etc/resolv.conf': Device or resource busy
rm: cannot remove '/etc/hostname': Device or resource busy
How to recover deleted files and directories?
UPD: according to comment about https://unix.stackexchange.com/questions/91297/how-to-undelete-just-deleted-directory-with-rm-r-command
It doest not work for me beacause I have removed /etc/ directory and unable to install any additional software inside docker container.
Your not going to be able to recover them reliably without a backup which would most likely come in the form of a docker commit of the container or a snapshot of the underlying docker filesystem.
You can get the original /etc back from the image you started the container from though, which is at least better than where you are now.
docker run {your_image} tar -cf - /etc | docker exec {your_container_missing_etc} tar -xvf -
{your_image} being the image your container is running.
{your_container_missing_etc} being the id or name of the container missing /etc