Changes between Version 3 and Version 4 of Docker

Timestamp:

07/18/2025 06:00:02 PM (3 months ago)

Author:

Tim Harvey

Comment:

update instructions to use more simplistic --volume arg for bind mounts

Docker

@@ -135 +135 @@
  - run container with a bind-mount from host {{{/usr/src/}}} to containers {{{/usr/src}}}
 {{{#!bash
-docker run -it --mount type=bind,source=/usr/src,target=/usr/src ubuntu-16.04
-}}}
- - run container in privileged mode (necessary to perform some root-specific functions like 'mount' within the container)
-{{{#!bash
-docker run --privileged -it --mount type=bind,source=/usr/src,target=/usr/src ubuntu-16.04
+docker run -it --volume /usr/src:/usr/src ubuntu-16.04
+}}}
+ - run container in privileged mode (necessary to access host devices within the container)
+{{{#!bash
+docker run --privileged -it --volume /usr/src:/usr/src ubuntu-16.04
 }}}
  - Notes:
@@ -177 +177 @@
  - run container with a bind-mount from host {{{/usr/src/}}} to containers {{{/usr/src}}}
 {{{#!bash
-docker run -it --mount type=bind,source=/usr/src,target=/usr/src ubuntu-16.04
+docker run -it --volume /usr/src:/usr/src ubuntu-16.04
 }}}
  - create a volume and mount it in a container:
@@ -198 +198 @@
 
 This example shows how to create an Ubuntu 20.04 Focal container from an Ubuntu host OS. The steps will vary a bit on other host Operating Systems.
+
+The example here creates a local user with sudo access using variables (USER, UID, GID) that can be specified when you build the image to make it easier to share files on your host when using a bind mount.
 
 1. Create a docker 'image' based on Ubuntu 20.04:
@@ -224 +226 @@
 
 # and set the prompt as a reminder 
-RUN echo 'export PS1="\u@focal:\w\$ "' >> /home/$USER/.bashrc
+RUN echo 'export PS1="\u@docker-focal:\w\$ "' >> /etc/bash.bashrc
 # switch to this user
 USER $USER
@@ -230 +232 @@
 EOF
 }}}
- - use the 'docker build' command to build the OS image:
-{{{#!bash
-docker build --tag ubuntu-22.04 --build-arg USER=$USER --build-arg UID=$(id -u) --build-arg GID=$(id -g) ubuntu-jammy/
+ - use the 'docker build' command to build the OS image passing in args for your USER, UID, GID
+{{{#!bash
+docker build --tag ubuntu-22.04 --build-arg USER=$USER --build-arg UID=$(id -u) --build-arg GID=$(id -g) ubuntu-focal/
 }}}
   * the '--build-arg' options above are optional but show how you can use your host Linux OS user/group to replace the default ones specified in the DockerFile. This can be very useful if you mount a filesystem from your host OS into your container and want to share user permissions
@@ -240 +242 @@
 {{{#!bash
 docker run -it --privileged \
-  --mount type=bind,source=/usr/src,target=/usr/src \
-  --mount type=bind,source=/tftpboot,target=/tftpboot \
+  --volume /home/$USER:/home/$USER \
+  --volume /tftpboot/tftpboot \
   --name jammy ubuntu-jammy
 }}}
- * the '--mount' options are optional but show how you can mount directories from your host OS to the container's OS. In this case we have mounted /tftpboot so we can copy files from the container to the hosts's tftpboot directory where a TFTP server may be running. We also mount /usr/src from the host OS to allow our host OS to get to source files we use
+ * the '--volume' options are optional but show how you can bind mount directories from your host OS to the container's OS. In this case we have mounted /tftpboot so we can copy files from the container to the hosts's tftpboot directory where a TFTP server may be running. We also mount your home director from the host OS to allow our host OS to get to source files we use
  * Note that once you 'run' a container it remains present even if you have detached from it meaning you can later re-attach to it
  * The '--it' option is a shortcut for '--interactive' and '--tty' which allocates a pseudo-TTY terminal and keeps STDIN open even if not attached. These options allow the bash process to start in the container, attaches the host OS console to the processes standard input/output/error, and allocates a text-only console.