====== erstes Docker Image selbst bauen ======
===== Pakete =====
  * Rocky Linux (9):
    * erst ''epel-release'' installieren (fügt neues Repository hinzu)
    * debootstrap
  * Debian (ab 12): debootstrap

===== Image bauen =====
(( anders als das Image aus https://hub.docker.com/_/debian ist dieses Image nicht reproduzierbar ))
  sudo debootstrap --variant=minbase trixie ./debian http://debian/debian
  sudo tar cC debian/ . | docker image import - ingo/debian:trixie
Tag ''latest'' hinzufügen:
  docker image ls ingo/debian:trixie
-> id rauskopieren (z.B. ''dc9f1edde160'')
  docker image tag dc9f1edde160 ingo/debian:latest

==== testen ====
  docker container run ingo/debian echo hello world

====== Dockerfile - Docker Images weiterbauen ======
  mkdir nginx
  cd nginx
<file txt Dockerfile>
FROM ingo/debian:trixie
LABEL version="0.0.1"
LABEL maintainer="me@example.com"
ENV DEBIAN_FRONTEND=noninteractive
ENV REFRESHED_AT=2026-01-07
RUN set -eux; \
  apt-get -qq update; \
  apt-get install -y --no-install-recommends nginx
RUN find / -xdev -user root -type f -perm /u+s -exec chmod u-s {} +
RUN echo 'A warm welcome from your Dockerfile' > /var/www/html/index.html
EXPOSE 80
ENTRYPOINT ["/usr/sbin/nginx", "-g", "daemon off;"]
</file>
  docker build -t='ingo/nginx:0.0.1' .
  docker image ls ingo/nginx:0.0.1
-> id rauskopieren (z.B. ''5879d7773761'')
  docker image tag 5879d7773761 ingo/nginx:latest
  docker container run -d -p 80:80 --name my_nginx ingo/nginx
  curl -s http://localhost:80
-> im Browser http://localhost öffnen

===== ENTRYPOINT / CMD / run-Command =====
^ ''ENTRYPOINT'' ^ ''CMD'' ^ run-Command ^ ausgeführt wird ^
|<code>["script.sh"]</code>|                          |                        | <code>script.sh</code> |
|<code>["script.sh"]</code>|                          | <code>/bin/dash</code> | <code>script.sh /bin/dash</code> |
|<code>["script.sh"]</code>| <code>["httpd"]</code>   |                        | <code>script.sh httpd</code> |
|<code>["script.sh"]</code>| <code>["httpd"]</code>   | <code>/bin/dash</code> | <code>script.sh /bin/dash</code> |
|                          | <code>["/bin/sh"]</code> |                        | <code>/bin/sh</code>   |
|                          | <code>["/bin/sh"]</code> | <code>/bin/dash</code> | <code>/bin/dash</code> |
|                          |                          |                        | <code>/bin/bash</code>((https://docs.docker.com/reference/dockerfile/#understand-how-cmd-and-entrypoint-interact sagt ''error, not allowed''. Docker Version 20.10.24+dfsg1 hat ''bash'' ausgeführt.)) |