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--- wiki2:docker-advanced [2018/12/22 15:54]
alfred [Save and load an image]
+++ wiki2:docker-advanced [2020/05/09 09:25] (actual)
@@ Línea 1: / Línea 1: @@
 ====== Docker Advanced ======
+===== Dockerfiles =====
+==== ARGS ====
+Con el comando ARGS puedes definir, dentro del Dockerfile, qué argumentos se pueden usar para construir una imagen:
+<code>
+ARG <name>[=<default value>]
+</code>
+En el siguiente ejemplo se añade un argumento sin valor por defecto ''user'', uno con valor por defecto ''3'' y luego se usa el argumento con la sintaxis ''$user''.
+<code>
+FROM busybox
+ARG user
+ARG buildno=3
+USER $user
+</code>
 ===== Images =====
@@ Línea 13: / Línea 31: @@
 ==== Save and load a physical image ====
+<code>
+docker save --output ../dist/puma-app-docker.tar gtd/puma_app:$VERSION
+</code>
+<code>
+docker load --input puma-app-docker.tar
+</code>
 ===== Networks =====
-===== Other concepts =====
+===== Volumenes =====
+<code>
+$ docker volume create portainer_data
+$ docker run -d -p 9000:9000 -v /var/run/docker.sock:/var/run/docker.sock -v portainer_data:/data portainer/portainer
+</code>
+Listar, eliminar... volumenes
+<code>
+$ docker volume ls
+$ docker volume rm <nombre_volumen>
+</code>
+==== Copiar un fichero a un volumen ====
+Imaginemos que queremos copiar un fichero a un volúmen que está siendo usado por un contenedor (y luego darle permisos y ejecutar una acción concreta):
+<code>
+$ docker cp file_backup.tar <container>:/var/opt/gitlab/backups
+$ docker exec <container> chown git:root /var/opt/gitlab/backups/COMA-CORE1-dataset_gitlab_backup.tar
+$ docker exec -it fa38 gitlab-rake gitlab:backup:restore
+</code>
+Siempre necesitaremos un contenedor corriendo para copiar el fichero, tenemos las siguientes opciones:
+<code>
+docker container create --name dummy -v myvolume:/root hello-world
+docker cp c:\myfolder\myfile.txt dummy:/root/myfile.txt
+docker rm dummy
+</code>
+En una línea:
+<code>
+docker run --rm -v $PWD:/source -v my_volume:/dest -w /source alpine cp myfile.txt /dest
+</code>
+O incluso en un contenedor creado desde cero con un Dockerfile con:
+<code>
+FROM scratch
+CMD
+</code>
+Luego:
+<code>
+docker build -t nothing .
+docker container create --name dummy -v myvolume:/root nothing
+docker cp c:\myfolder\myfile.txt dummy:/root/myfile.txt
+docker rm dummy
+</code>
+==== Creación de un volumen mapeado en nfs (docker-compose) ====
+<code yml>
+volumes:
+  nas-owncloud:
+    driver: local
+    driver_opts:
+      type: nfs
+      o: "addr=10.10.10.10,nolock,soft,rw"
+      device: ":/volume1/sir-vices/owncloud"
+services:
+  owncloud:
+    volumes:
+      - nas-owncloud:/mnt/data
+</code>
+===== Compose =====
+==== Environment variables ====
+It’s possible to use environment variables in your shell to populate values inside a Compose file:
+<code>
+web:
+  image: "webapp:${TAG}"
+</code>
+You can set environment variables with the ''environment'' key, just like with ''docker run -e VARIABLE=VALUE ...'':
+<code>
+web:
+  environment:
+    - DEBUG=1
+</code>
+Pass environment variables to containers without giving a value:
+<code>
+web:
+  environment:
+    - DEBUG
+</code>
+You can pass multiple environment variables from an external file with the ''env_file'' option, just like with ''docker run --env-file=FILE ...'':
+<code>
+web:
+  env_file:
+    - web-variables.env
+</code>
+Just like with ''docker run -e'', you can set environment variables with ''docker-compose run -e'':
+<code>
+docker-compose run -e DEBUG=1 web python console.py
+</code>
+You can also pass a variable through from the shell by not giving it a value:
+<code>
+docker-compose run -e DEBUG web python console.py
+</code>
+You can set default values for any environment variables referenced in the Compose file, or used to configure Compose, in an environment file named .env:
+<code>
+$ cat .env
+TAG=v1.5
+$ cat docker-compose.yml
+version: '3'
+services:
+  web:
+    image: "webapp:${TAG}"
+</code>
+===== Execute GUI programs =====
+You can create a Dockerfile where you install a Firefox, a Visual Studio Code... Whatever. Then, as the X11 Linux programs work like client\server you only need to bind the socket. \\
+For example, a Dockerfile could be this:
+<code>
+FROM ubuntu:14.04
+RUN apt-get update && apt-get install -y firefox
+RUN export uid=1000 gid=1000 && \
+    mkdir -p /home/developer && \
+    echo "developer:x:${uid}:${gid}:Developer,,,:/home/developer:/bin/bash" >> /etc/passwd && \
+    echo "developer:x:${uid}:" >> /etc/group && \
+    echo "developer ALL=(ALL) NOPASSWD: ALL" > /etc/sudoers.d/developer && \
+    chmod 0440 /etc/sudoers.d/developer && \
+    chown ${uid}:${gid} -R /home/developer
+USER developer
+ENV HOME /home/developer
+CMD /usr/bin/firefox
+</code>
+Then you only need to buid it:
+<code>
+docker build -t firefox .
+</code>
+And launch it using your x11 socket:
+<code>
+docker run -ti --rm \
+       -e DISPLAY=$DISPLAY \
+       -v /tmp/.X11-unix:/tmp/.X11-unix \
+       firefox
+</code>
+You could also use the run with the cmd as parameter, in this way you could install several programs and launch them with this.
+==== Launch them from SSH ====
+As it says here [[https://docs.docker.com/engine/examples/running_ssh_service/]] you can create a Dockerfile with...
+<code>
+FROM ubuntu:16.04
+RUN apt-get update && apt-get install -y openssh-server
+RUN mkdir /var/run/sshd
+RUN echo 'root:THEPASSWORDYOUCREATED' | chpasswd
+RUN sed -i 's/PermitRootLogin prohibit-password/PermitRootLogin yes/' /etc/ssh/sshd_config
+# SSH login fix. Otherwise user is kicked off after login
+RUN sed 's@session\s*required\s*pam_loginuid.so@session optional pam_loginuid.so@g' -i /etc/pam.d/sshd
+ENV NOTVISIBLE "in users profile"
+RUN echo "export VISIBLE=now" >> /etc/profile
+EXPOSE 22
+CMD ["/usr/sbin/sshd", "-D"]
+</code>
+... for an ssh server.
+This one will be prepared for launching a remote firefox in your local machine if you connect to it via ssh and launch it.
+<code>
+FROM ubuntu:14.04
+RUN apt-get update && apt-get install -y firefox openssh-server
+RUN mkdir /var/run/sshd
+RUN echo 'root:train' | chpasswd
+RUN sed -i 's/PermitRootLogin without-password/PermitRootLogin yes/' /etc/ssh/sshd_config
+# SSH login fix. Otherwise user is kicked off after login
+RUN sed 's@session\s*required\s*pam_loginuid.so@session optional pam_loginuid.so@g' -i /etc/pam.d/sshd
+ENV NOTVISIBLE "in users profile"
+RUN echo "export VISIBLE=now" >> /etc/profile
+RUN echo "X11UseLocalhost no" >> /etc/ssh/sshd_config
+EXPOSE 22
+CMD ["/usr/sbin/sshd", "-D"]
+# CMD tail -f /dev/null
+</code>

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