COPY in Dockerfile does not work

Question

Hi everyone,

I want to change my hostname throgh the Dockerfile copying a local file hosts in /etc/hosts but does not work.

This is my Dockerfile:

FROM  ubuntu

RUN apt-get update && apt-get install -y bind9 bind9utils bind9-doc

COPY hosts /etc/hosts
COPY named.conf.local /etc/bind/named.conf.local

The file called named.conf.local is successfully copied in my container while hosts file not. Anyone knows the problem?

Thank you.

Comments

Instead Copy, you can try CMD cat hosts >> /etc/hosts;

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Should be permission issue

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replacing the hosts file does not change your hostname. why do you want to change the hostname at all?

Answer 1

Your query is similar to https://www.edureka.co/community/7415/copy-is-not-working-in-docker Check this out!

Answer 2

1. RUN hostname new-server-name

2. RUN echo "new-server-name" >> /etc/hostname

3. RUN echo "127.0.0.1 new-server-name" >> /etc/hosts?

Answer 3

You cannot overwrite /etc/hosts in a docker container. That file is exclusively managed by the docker daemon. You can, however add host entries with the extra-hosts instruction. These hosts are then used to generate the hosts file when the container starts up.