Is it possible to exclude a specific subdirectory from a podman volume mount? - containers

For example, let's say you have a directory dir/ with an arbitrary number of subdirectories including dir/subdir/, and you want to mount dir/ to a podman container with every subdirectory also mounted except dir/subdir/.
Is this possible in podman? If so, is it possible to do this purely with the arguments of a podman run command?

Is not possible, the entire folder will be available inside the container.
You can overcome this with permissions, acl or even symbolic links. In the last case, create a second folder with links pointing to only the folders you want to be available inside the container.

Use an extra bind-mount to hide the directory dir/subdir/
In other words, first bind-mount dir/ and then bind-mount an empty directory over dir/subdir to hide its contents.
$ mkdir dir
$ mkdir dir/subdir
$ mkdir dir/subdir2
$ mkdir emptydir
$ touch dir/subdir/file1.txt
$ touch dir/subdir2/file2.txt
$ podman pull -q docker.io/library/fedora
b2aa39c304c27b96c1fef0c06bee651ac9241d49c4fe34381cab8453f9a89c7d
$ podman run --rm \
-v ./dir:/dir:Z \
-v ./emptydir:/dir/subdir:Z \
docker.io/library/fedora find /dir
/dir
/dir/subdir
/dir/subdir2
/dir/subdir2/file2.txt
In the output from the command find /dir there is no file dir/subdir/file1.txt

Related

How to use external files as arguments in Docker images [duplicate]

I am trying to mount a host directory into a Docker container so that any updates done on the host is reflected into the Docker containers.
Where am I doing something wrong. Here is what I did:
kishore$ cat Dockerfile
FROM ubuntu:trusty
RUN apt-get update
RUN apt-get -y install git curl vim
CMD ["/bin/bash"]
WORKDIR /test_container
VOLUME ["/test_container"]
kishore$ tree
.
├── Dockerfile
└── main_folder
├── tfile1.txt
├── tfile2.txt
├── tfile3.txt
└── tfile4.txt
1 directory, 5 files
kishore$ pwd
/Users/kishore/tdock
kishore$ docker build --tag=k3_s3:latest .
Uploading context 7.168 kB
Uploading context
Step 0 : FROM ubuntu:trusty
---> 99ec81b80c55
Step 1 : RUN apt-get update
---> Using cache
---> 1c7282005040
Step 2 : RUN apt-get -y install git curl vim
---> Using cache
---> aed48634e300
Step 3 : CMD ["/bin/bash"]
---> Running in d081b576878d
---> 65db8df48595
Step 4 : WORKDIR /test_container
---> Running in 5b8d2ccd719d
---> 250369b30e1f
Step 5 : VOLUME ["/test_container"]
---> Running in 72ca332d9809
---> 163deb2b1bc5
Successfully built 163deb2b1bc5
Removing intermediate container b8bfcb071441
Removing intermediate container d081b576878d
Removing intermediate container 5b8d2ccd719d
Removing intermediate container 72ca332d9809
kishore$ docker run -d -v /Users/kishore/main_folder:/test_container k3_s3:latest
c9f9a7e09c54ee1c2cc966f15c963b4af320b5203b8c46689033c1ab8872a0eakishore$ docker run -i -t k3_s3:latest /bin/bash
root#0f17e2313a46:/test_container# ls -al
total 8
drwx------ 2 root root 4096 Apr 29 05:15 .
drwxr-xr-x 66 root root 4096 Apr 29 05:15 ..
root#0f17e2313a46:/test_container# exit
exitkishore$ docker -v
Docker version 0.9.1, build 867b2a9
I don't know how to check boot2docker version
Questions, issues facing:
How do I need to link the main_folder to the test_container folder present inside the docker container?
I need to make this automatically. How do I to do that without really using the run -d -v command?
What happens if the boot2docker crashes? Where are the Docker files stored (apart from Dockerfile)?
There are a couple ways you can do this. The simplest way to do so is to use the dockerfile ADD command like so:
ADD . /path/inside/docker/container
However, any changes made to this directory on the host after building the dockerfile will not show up in the container. This is because when building a container, docker compresses the directory into a .tar and uploads that context into the container permanently.
The second way to do this is the way you attempted, which is to mount a volume. Due to trying to be as portable as possible you cannot map a host directory to a docker container directory within a dockerfile, because the host directory can change depending on which machine you are running on. To map a host directory to a docker container directory you need to use the -v flag when using docker run, e.g.,:
# Run a container using the `alpine` image, mount the `/tmp`
# directory from your host into the `/container/directory`
# directory in your container, and run the `ls` command to
# show the contents of that directory.
docker run \
-v /tmp:/container/directory \
alpine \
ls /container/directory
The user of this question was using Docker version 0.9.1, build 867b2a9, I will give you an answer for docker version >= 17.06.
What you want, keep local directory synchronized within container directory, is accomplished by mounting the volume with type bind. This will bind the source (your system) and the target (at the docker container) directories. It's almost the same as mounting a directory on linux.
According to Docker documentation, the appropriate command to mount is now mount instead of -v. Here's its documentation:
--mount: Consists of multiple key-value pairs, separated by commas. Each key/value pair takes the form of a <key>=<value> tuple. The --mount syntax is more verbose than -v or --volume, but the order of the keys is not significant, and the value of the flag is easier to understand.
The type of the mount, which can be bind, volume, or tmpfs. (We are going to use bind)
The source of the mount. For bind mounts, this is the path to the file or directory on the Docker daemon host. May be specified as source or src.
The destination takes as its value the path where the file or directory will be mounted in the container. May be specified as destination, dst, or target.
So, to mount the the current directory (source) with /test_container (target) we are going to use:
docker run -it --mount src="$(pwd)",target=/test_container,type=bind k3_s3
If these mount parameters have spaces you must put quotes around them. When I know they don't, I would use `pwd` instead:
docker run -it --mount src=`pwd`,target=/test_container,type=bind k3_s3
You will also have to deal with file permission, see this article.
you can use -v option from cli, this facility is not available via Dockerfile
docker run -t -i -v <host_dir>:<container_dir> ubuntu /bin/bash
where host_dir is the directory from host which you want to mount.
you don't need to worry about directory of container if it doesn't exist docker will create it.
If you do any changes in host_dir from host machine (under root privilege) it will be visible to container and vice versa.
2 successive mounts:
I guess many posts here might be using two boot2docker, the reason you don't see anything is that you are mounting a directory from boot2docker, not from your host.
You basically need 2 successive mounts:
the first one to mount a directory from your host to your system
the second to mount the new directory from boot2docker to your container like this:
1) Mount local system on boot2docker
sudo mount -t vboxsf hostfolder /boot2dockerfolder
2) Mount boot2docker file on linux container
docker run -v /boot2dockerfolder:/root/containerfolder -i -t imagename
Then when you ls inside the containerfolder you will see the content of your hostfolder.
Is it possible that you use docker on OS X via boot2docker or something similar.
I've made the same experience - the command is correct but nothing (sensible) is mounted in the container, anyway.
As it turns out - it's already explained in the docker documentation. When you type docker run -v /var/logs/on/host:/var/logs/in/container ... then /var/logs/on/host is actually mapped from the boot2docker VM-image, not your Mac.
You'll have to pipe the shared folder through your VM to your actual host (the Mac in my case).
For those who wants to mount a folder in current directory:
docker run -d --name some-container -v ${PWD}/folder:/var/folder ubuntu
I'm just experimenting with getting my SailsJS app running inside a Docker container to keep my physical machine clean.
I'm using the following command to mount my SailsJS/NodeJS application under /app:
cd my_source_code_folder
docker run -it -p 1337:1337 -v $(pwd):/app my_docker/image_with_nodejs_etc
[UPDATE] As of ~June 2017, Docker for Mac takes care of all the annoying parts of this where you have to mess with VirtualBox. It lets you map basically everything on your local host using the /private prefix. More info here. [/UPDATE]
All the current answers talk about Boot2docker. Since that's now deprecated in favor of docker-machine, this works for docker-machine:
First, ssh into the docker-machine vm and create the folder we'll be mapping to:
docker-machine ssh $MACHINE_NAME "sudo mkdir -p \"$VOL_DIR\""
Now share the folder to VirtualBox:
WORKDIR=$(basename "$VOL_DIR")
vboxmanage sharedfolder add "$MACHINE_NAME" --name "$WORKDIR" --hostpath "$VOL_DIR" --transient
Finally, ssh into the docker-machine again and mount the folder we just shared:
docker-machine ssh $MACHINE_NAME "sudo mount -t vboxsf -o uid=\"$U\",gid=\"$G\" \"$WORKDIR\" \"$VOL_DIR\""
Note: for UID and GID you can basically use whatever integers as long as they're not already taken.
This is tested as of docker-machine 0.4.1 and docker 1.8.3 on OS X El Capitan.
Using command-line :
docker run -it --name <WHATEVER> -p <LOCAL_PORT>:<CONTAINER_PORT> -v <LOCAL_PATH>:<CONTAINER_PATH> -d <IMAGE>:<TAG>
Using docker-compose.yaml :
version: '2'
services:
cms:
image: <IMAGE>:<TAG>
ports:
- <LOCAL_PORT>:<CONTAINER_PORT>
volumes:
- <LOCAL_PATH>:<CONTAINER_PATH>
Assume :
IMAGE: k3_s3
TAG: latest
LOCAL_PORT: 8080
CONTAINER_PORT: 8080
LOCAL_PATH: /volume-to-mount
CONTAINER_PATH: /mnt
Examples :
First create /volume-to-mount. (Skip if exist)
$ mkdir -p /volume-to-mount
docker-compose -f docker-compose.yaml up -d
version: '2'
services:
cms:
image: ghost-cms:latest
ports:
- 8080:8080
volumes:
- /volume-to-mount:/mnt
Verify your container :
docker exec -it CONTAINER_ID ls -la /mnt
docker run -v /host/directory:/container/directory -t IMAGE-NAME /bin/bash
docker run -v /root/shareData:/home/shareData -t kylemanna/openvpn /bin/bash
In my system I've corrected the answer from nhjk, it works flawless when you add the -t flag.
On Mac OS, to mount a folder /Users/<name>/projects/ on your mac at the root of your container:
docker run -it -v /Users/<name>/projects/:/projects <container_name> bash
ls /projects
If the host is windows 10 then instead of forward slash, use backward slash -
docker run -it -p 12001:80 -v c:\Users\C\Desktop\dockerStorage:/root/sketches
Make sure the host drive is shared (C in this case). In my case I got a prompt asking for share permission after running the command above.
For Windows 10 users, it is important to have the mount point inside the C:/Users/ directory. I tried for hours to get this to work. This post helped but it was not obvious at first as the solution for Windows 10 is a comment to an accepted answer. This is how I did it:
docker run -it -p 12001:80 -v //c/Users/C/Desktop/dockerStorage:/root/sketches \
<your-image-here> /bin/bash
Then to test it, you can do echo TEST > hostTest.txt inside your image. You should be able to see this new file in the local host folder at C:/Users/C/Desktop/dockerStorage/.
As of Docker 18-CE, you can use docker run -v /src/path:/container/path to do 2-way binding of a host folder.
There is a major catch here though if you're working with Windows 10/WSL and have Docker-CE for Windows as your host and then docker-ce client tools in WSL. WSL knows about the entire / filesystem while your Windows host only knows about your drives. Inside WSL, you can use /mnt/c/projectpath, but if you try to docker run -v ${PWD}:/projectpath, you will find in the host that /projectpath/ is empty because on the host /mnt means nothing.
If you work from /c/projectpath though and THEN do docker run -v ${PWD}:/projectpath and you WILL find that in the container, /projectpath will reflect /c/projectpath in realtime. There are no errors or any other ways to detect this issue other than seeing empty mounts inside your guest.
You must also be sure to "share the drive" in the Docker for Windows settings.
Jul 2015 update - boot2docker now supports direct mounting. You can use -v /var/logs/on/host:/var/logs/in/container directly from your Mac prompt, without double mounting
I've been having the same issue.
My command line looked like this:
docker run --rm -i --name $NAME -v `pwd`:/sources:z $NAME
The problem was with 'pwd'. So I changed that to $(pwd):
docker run --rm -i --name $NAME -v $(pwd):/sources:z $NAME
How do I link the main_folder to the test_container folder present inside the docker container?
Your command below is correct, unless your on a mac using boot2docker(depending on future updates) in which case you may find the folder empty. See mattes answer for a tutorial on correcting this.
docker run -d -v /Users/kishore/main_folder:/test_container k3_s3:latest
I need to make this run automatically, how to do that without really
using the run -d -v command.
You can't really get away from using these commands, they are intrinsic to the way docker works. You would be best off putting them into a shell script to save you writing them out repeatedly.
What happens if boot2docker crashes? Where are the docker files stored?
If you manage to use the -v arg and reference your host machine then the files will be safe on your host.
If you've used 'docker build -t myimage .' with a Dockerfile then your files will be baked into the image.
Your docker images, i believe, are stored in the boot2docker-vm. I found this out when my images disappeared when i delete the vm from VirtualBox. (Note, i don't know how Virtualbox works, so the images might be still hidden somewhere else, just not visible to docker).
Had the same problem. Found this in the docker documentation:
Note: The host directory is, by its nature, host-dependent. For this reason, you can’t mount a host directory from Dockerfile, the VOLUME instruction does not support passing a host-dir, because built images should be portable. A host directory wouldn’t be available on all potential hosts.
So, mounting a read/write host directory is only possible with the -v parameter in the docker run command, as the other answers point out correctly.
I found that any directory laying under system directive like /var, /usr, /etc could not be mount under the container.
The directive should be at user's space -v switch instructs docker daemon to mount local directory to the container, for example:
docker run -t -d -v /{local}/{path}:/{container}/{path} --name {container_name} {imagename}
Here's an example with a Windows path:
docker run -P -it --name organizr --mount src="/c/Users/MyUserName/AppData/Roaming/DockerConfigs/Organizr",dst=/config,type=bind organizrtools/organizr-v2:latest
As a side note, during all of this hair pulling, having to wrestle with figuring out, and retyping paths over and over and over again, I decided to whip up a small AutoHotkey script to convert a Windows path to a "Docker Windows" formatted path. This way all I have to do is copy any Windows path that I want to use as a mount point to the clipboard, press the "Apps Key" on the keyboard, and it'll format it into a path format that Docker appreciates.
For example:
Copy this to your clipboard:
C:\Users\My PC\AppData\Roaming\DockerConfigs\Organizr
press the Apps Key while the cursor is where you want it on the command-line, and it'll paste this there:
"/c/Users/My PC/AppData/Roaming/DockerConfigs/Organizr"
Saves a lot to time for me. Here it is for anyone else who may find it useful.
; --------------------------------------------------------------------------------------------------------------
;
; Docker Utility: Convert a Windows Formatted Path to a Docker Formatter Path
; Useful for (example) when mounting Windows volumes via the command-line.
;
; By: J. Scott Elblein
; Version: 1.0
; Date: 2/5/2019
;
; Usage: Cut or Copy the Windows formatted path to the clipboard, press the AppsKey on your keyboard
; (usually right next to the Windows Key), it'll format it into a 'docker path' and enter it
; into the active window. Easy example usage would be to copy your intended volume path via
; Explorer, place the cursor after the "-v" in your Docker command, press the Apps Key and
; then it'll place the formatted path onto the line for you.
;
; TODO:: I may or may not add anything to this depending on needs. Some ideas are:
;
; - Add a tray menu with the ability to do some things, like just replace the unformatted path
; on the clipboard with the formatted one rather than enter it automatically.
; - Add 'smarter' handling so the it first confirms that the clipboard text is even a path in
; the first place. (would need to be able to handle Win + Mac + Linux)
; - Add command-line handling so the script doesn't need to always be in the tray, you could
; just pass the Windows path to the script, have it format it, then paste and close.
; Also, could have it just check for a path on the clipboard upon script startup, if found
; do it's job, then exit the script.
; - Add an 'all-in-one' action, to copy the selected Windows path, and then output the result.
; - Whatever else comes to mind.
;
; --------------------------------------------------------------------------------------------------------------
#NoEnv
SendMode Input
SetWorkingDir %A_ScriptDir%
AppsKey::
; Create a new var, store the current clipboard contents (should be a Windows path)
NewStr := Clipboard
; Rip out the first 2 chars (should be a drive letter and colon) & convert the letter to lowercase
; NOTE: I could probably replace the following 3 lines with a regexreplace, but atm I'm lazy and in a rush.
tmpVar := SubStr(NewStr, 1, 2)
StringLower, tmpVar, tmpVar
; Replace the uppercase drive letter and colon with the lowercase drive letter and colon
NewStr := StrReplace(NewStr, SubStr(NewStr, 1, 2), tmpVar)
; Replace backslashes with forward slashes
NewStr := StrReplace(NewStr, "\", "/")
; Replace all colons with nothing
NewStr := StrReplace(NewStr, ":", "")
; Remove the last char if it's a trailing forward slash
NewStr := RegExReplace(NewStr, "/$")
; Append a leading forward slash if not already there
if RegExMatch(NewStr, "^/") == 0
NewStr := "/" . NewStr
; If there are any spaces in the path ... wrap in double quotes
if RegExMatch(NewStr, " ") > 0
NewStr := """" . NewStr . """"
; Send the result to the active window
SendInput % NewStr
To get this working in Windows 10 I had to open the Docker Settings window from the system tray and go to the Shared Drives section.
I then checked the box next to C. Docker asked for my desktop credentials to gain authorisation to write to my Users folder.
Then I ran the docker container following examples above and also the example on that settings page, attaching to /data in the container.
docker run -v c:/Users/<user.name>/Desktop/dockerStorage:/data -other -options
boot2docker together with VirtualBox Guest Additions
How to mount /Users into boot2docker
https://medium.com/boot2docker-lightweight-linux-for-docker/boot2docker-together-with-virtualbox-guest-additions-da1e3ab2465c
tl;dr Build your own custom boot2docker.iso with VirtualBox Guest
Additions (see link) or download
http://static.dockerfiles.io/boot2docker-v1.0.1-virtualbox-guest-additions-v4.3.12.iso
and save it to ~/.boot2docker/boot2docker.iso.
Note that in Windows you'll have to provide the absolute path.
Host: Windows 10
Container: Tensorflow Notebook
Below worked for me.
docker run -t -i -v D:/projects/:/home/chankeypathak/work -p 8888:8888 jupyter/tensorflow-notebook /bin/bash
i had same issues , i was trying to mount C:\Users\ folder on docker
this is how i did it Docker Toolbox command line
$ docker run -it --name <containername> -v /c/Users:/myVolData <imagename>
You can also do this with Portainer web application for a different visual experience.
First pull the Portainer image:
docker pull portainer/portainer
Then create a volume for Portainer:
docker volume create portainer_data
Also create a Portainer container:
docker run -d -p 8000:8000 -p 9000:9000 --name=portainer --restart=always -v /var/run/docker.sock:/var/run/docker.sock -v portainer_data:/data portainer/portainer
You will be able to access the web app with your browser at this URL: "http://localhost:9000". At the first login, you will be prompted to set your Portainer admin credentials.
In the web app, follow these menus and buttons: (Container > Add container > Fill settings > Deploy Container)
I had trouble to create a "mount" volume with Portainer and I realized I had to click "bind" when creating my container's volume. Below is an illustration of the volume binding settings that worked for my container creation with a mounted volume binded to the host.
P.S.: I'm using Docker 19.035 and Portainer 1.23.1
I had the same requirement to mount host directory from container and I used volume mount command. But during testing noticed that it's creating files inside container too but after some digging found that they are just symbolic links and actual file system used form host machine.
Quoting from the Official Website:
Make sure you don’t have any previous getting-started containers running.
Run the following command from the app directory.
x86-64 Mac or Linux device:
docker run -dp 3000:3000 \
-w /app -v "$(pwd):/app" \
node:12-alpine \
sh -c "yarn install && yarn run dev"
Windows (PowerShell):
docker run -dp 3000:3000 `
-w /app -v "$(pwd):/app" `
node:12-alpine `
sh -c "yarn install && yarn run dev"
Aple silicon Mac or another ARM64 device:
docker run -dp 3000:3000 \
-w /app -v "$(pwd):/app" \
node:12-alpine \
sh -c "apk add --no-cache python2 g++ make && yarn install && yarn run dev"
Explaining:
dp 3000:3000 - same as before. Run in detached (background) mode and create a port mapping
w /app - sets the “working directory” or the current directory that the command will run from
v "$(pwd):/app" - bind mount the current directory from the host into the /app directory in the container
node:12-alpine - the image to use.
Note that this is the base image for our app from the Dockerfile sh -c "yarn install && yarn run dev" - the command.
We’re starting a shell using sh (alpine doesn’t have bash) and running yarn install to install all dependencies and then running yarn run dev. If we look in the package.json, we’ll see that the dev script is starting nodemon.

How to generate code coverage with running lcov program at the same time

I have a large project with unittest binaries running on the other machines. So, the gcda files were generated on the other machines. Then, I download them to the local machine but the different dirs. Each of the dirs has the sources code.
For example: dir gcda1/src/{*.gcda, *.gcno, *.h, *.cpp}..., dir gcda2/src/{*.gcda, *.gcno, *.h, *.cpp}....
Because the project is very large, so I have to run multiple lcov processes at the same time to generate info files to save time. And then merge these info files.
The problem is, when I merge these info files, it will take dir infos, for example:
gcda1/src/unittest1.cpp
gcda2/src/unittest1.cpp
I want this:
src/unittest1.cpp
#src/unittest1.cpp # this is expected to merge with above
The commands I use:
$ cd gcda1
$ lcov --rc lcov_branch_coverage=1 -c -d ./ -b ./ --no-external -o gcda1.info
$ cd ../gcda2
$ lcov --rc lcov_branch_coverage=1 -c -d ./ -b ./ --no-external -o gcda2.info
$ cd ..
$ lcov -a gcda1/gcda1.info -a gcda1/gcda2.info -o gcda.info
$ genhtml gcda.info -o output
The root dir contains the source code.
Description
Well, I have found a method to solve this problem finally.
The info files lcov generated are plain text file. So we can edit them directly.
Once you open these files, you will see every file line start with SF. Like below:
SF:/path/to/your/source/code.h
SF:/path/to/your/source/code.cpp
...
Problem
In my problem, these will be:
// file gcda1.info
SF:/path/to/root_dir/gcda1/src/unittest1.cpp
// file gcda2.info
SF:/path/to/root_dir/gcda2/src/unittest1.cpp
And, after lcov merge, it will be:
// file gcda.info
SF:/path/to/root_dir/gcda1/src/unittest1.cpp
SF:/path/to/root_dir/gcda2/src/unittest1.cpp
But, I expect this:
// file gcda.info
SF:/path/to/root_dir/src/unittest1.cpp
Method
My method to solve the problem is editing the info files directly.
First, edit gcda1.info and gcda2.info, change /path/to/root_dir/gcda1/src/unittest1.cpp to /path/to/root_dir/src/unittest1.cpp, and /path/to/root_dir/gcda2/src/unittest1.cpp to /path/to/root_dir/src/unittest1.cpp.
Then merge them like below and generate html report:
$ lcov -a gcda1.info -a gcda2.info -o gcda.info
$ genhtml gcda.info -o output
In a large project, we could not manually edit each info file, otherwise you will collapse.
We can use sed to help us. Like below:
$ sed "s/\(^SF.*\/\)gcda[0-9]+\/\(.*\)/\1\2/g" gcda_tmp.info > gcda.info

Cannot delete files on docker host

I'm using the following shell script to extract my databases in the entrypoint and startup the container.
#!/bin/bash
if [ ! -d "/var/lib/mysql/assetmanager" ]; then
tar -zxvf mysql.tar.gz
fi
exec /usr/bin/mysqld_safe
On startup I mount a local directory to the /var/lib/mysql directory with the -v parameter and extract then the files with the above script.
But now I can't delete the extracted files on my host, because permission denied error.
Can someone help me with this problem.
Thx
You cannot delete them because by default process in container executed by root user and extracted files belong to root. if you don't need these files in mapped dir, use different location for it -v ...:/myassets and in script:
if [ ! -d "/var/lib/mysql/assetmanager" ]; then
tar -zxvf /myassets/mysql.tar.gz
fi
you also could map a single file instead of whole directory if you need only that file.
There are many other solutions, depends what you need:
you could delete these files as root: sudo rm ...
you could delete them in container before exit
you could create user in container and create files from this user

docker cp doesn't work for this mysql container

Tried copying a directory and it doesn't seem to work.
Start a MySQL container.
docker cp mysql:/var/lib/mysql .
cd mysql
ls
NOTHING.
Here's the script to try it yourself.
extra info.
On Ubuntu 14.04
jc#dev:~/work/jenkins/copy-sql/mysql$ docker -v
Docker version 1.2.0, build fa7b24f
In the Dockerfile for the image your container comes from, there is the VOLUME instruction which tells Docker to leave the /var/lib/mysql directory out of the container filesystem.
The docker cp can only access the container filesystem and thus won't see the files in mounted volumes.
If you need to backup your mysql data, I suggest you follow the instructions from the Docker userguide in section Backup, restore, or migrate data volumes. You might also find the discordianfish/docker-backup docker image useful for that task.
Here's a little example to illustrate your case.
given a simple Dockerfile with just a VOLUME instruction
$ cat Dockerfile
FROM base
VOLUME /data
build an image named test
$ docker build --force-rm -t test .
run a container named container_1 which will create two files, one being on the mounted volume
$ docker run -d --name container_1 test bash -c 'echo foo > /data/foo.txt; echo bar > /tmp/bar.txt; while true; do sleep 1; done'
make sure the container is running
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
9e97aa18ac83 test:latest "bash -c 'echo foo > 3 seconds ago Up 2 seconds container_1
use the docker cp command to cp file /tmp/bar.txt and check its content
$ docker cp container_1:/tmp/bar.txt .
$ cat bar.txt
bar
try the same with the file which is in the mounted volume (won't work)
$ docker cp container_1:/data/foo.txt .
2014/09/27 00:03:43 Error response from daemon: Could not find the file /data/foo.txt in container container_1
now run a second container to print out the content of that file
$ docker run --rm --volumes-from container_1 base cat /data/foo.txt
foo
It looks like you're trying to pass the name of your container to the docker cp command. The docs say it takes a container id. Try grepping for "CONTAINER ID" in your script instead.
EDIT:
Since changing your script to grep for the Container ID didn't help, you should start by trying this manually (outside of your script).
The docker cp command works. The reason it's not working for you is either:
a permission thing
you're not formatting the command correctly, or
the directory doesn't exist in your container.
With a running container id of XXXX, try this (using your container id):
sudo docker cp XXXX:/var/lib/mysql .
If this doesn't work, and you don't get an error, I'd maybe suggest that that directory doesn't exist in your container.
EDIT2:
As I said, it's one of the 3 things above.
I get this when I run your script:
2014/09/26 16:10:18 lchown mysql: operation not permitted
Changing the last line of your script to prefix with sudo now gives no errors, but no directory either.
Run the container interactively:
docker run -t -i mysql /bin/bash
Once inside the container:
cd /var/lib/mysql
ls
...no files.
So your script is working fine. The directory is just empty (basically #3 above).
For reference, the mysql Dockerfile is here.

Creating custom DVD for RHEL 7 with kickstart

I am trying to create a custom CD/DVD to deploy RHEL 7 with kickstart file. Here is what I did:
Edited isolinux.cfg (in the ISOLinux folder) and grub.cfg file (in the EFI\BOOT folder).
Created ISO using mkisofs.
But it is not working. Am I using correct files/method?
Edit the ISO image and put the ks.cfg file that you have created.
Preferably, put the ks.cfg file inside ks directory. More information can be found here.
You need to use the new command. Here is an example of what will work:
Add the kickstart file to your download and exploded ISO.
Run this command in the area with the ISO and kickstart and point to another location to build the ISO:
genisoimage -r -v -V "OEL6 with KS for OVM Manager" -cache-inodes -J -l -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -o OEL6U6_OVM_Manager.iso /var/www/html/Template/ISO/
I found the way to create custom DVD from the RHEL7 page.
Mount the downloaded image
mount -t iso9660 -o loop path/to/image.iso /mnt/iso
Create a working directory - a directory where you want to place the contents of the ISO image.
mkdir /tmp/ISO
Copy all contents of the mounted image to your new working directory. Make sure to use the -p option to preserve file and directory permissions and ownership.
cp -pRf /mnt/iso /tmp/ISO
Unmount the image.
umount /mnt/iso
Make sure your current working directory is the top-level directory of the extracted ISO image - e.g. /tmp/ISO/iso. Create the new ISO image using genisoimage:
genisoimage -U -r -v -T -J -joliet-long -V "RHEL-7.1 Server.x86_64" -Volset "RHEL-7.1 Server.x86_64" -A "RHEL-7.1 Server.x86_64" -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e images/efiboot.img -no-emul-boot -o ../NEWISO.iso .
Hope the answer will helpful:
I am editing my answer due to the comments posted. Here is a more comprehensive solution:
(A) You need to create the ISO properly. I found helpful information in this URL.
Here is the line that I actually ended up with, for my MBR/UEFI ISO creation:
mkisofs -U -A "<Volume Header>" -V "RHEL-7.1 x86_64" -volset "RHEL-7.1 x86_64" -J -joliet-long -r -v -T -x ./lost+found -o ${OUTPUT}/${HOST}.iso -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e images/efiboot.img -no-emul-boot -boot-load-size 18755 /dir/where/sources/for/ISO/are/located
Be careful with the -V parameter, as it has to match what the kernel has defined for inst.stage2. In the default grub.conf included in the boot disk, it is configured to be "hd:LABEL=RHEL-7.1\x20x86_64" which matches with the settings above.
(B) You need the correct setup for EFI for RHEL7. For some reason, this has changed from RHEL6, where you could just use the /EFI/BOOT/BOOTX64.conf. Now it uses the /EFI/BOOT/grub.cfg. Common wisdom from Red Hat Manuals state to add the inst.ks= parameter to the kernel line. The grub.cfg that comes in the /EFI/BOOT directory of the RHEL7 boot iso actually has the linuxefi parameter, instead of the kernel one, I would guess they would work the same. If you are including the KS file on the CD, this should get you there.
Good Luck!