Docker/Volumes - Revision history

Admin: /* Mounting Host Folders */

2017-04-05T07:17:13Z

Mounting Host Folders

← Older revision		Revision as of 07:17, 5 April 2017
Line 23:		Line 23:
	==Mounting Host Folders==		==Mounting Host Folders==

	Can mount folders on the host machine to drives in the docker machine:		Can mount folders on the host machine to drives in the docker machine using the -v flag when calling docker run.

			See docker run docs for details: https://docs.docker.com/engine/reference/run/

			<pre>
			$ docker run \
			-v /host/path:/container/path:options
			</pre>

			For example, this will mount the current directory to the same location inside the docker container, and set that location as the working directory for the new image:

	<pre>		<pre>

Admin: /* Mounting a Data Volume Container */

2017-03-25T03:49:10Z

Mounting a Data Volume Container

← Older revision		Revision as of 03:49, 25 March 2017
Line 102:		Line 102:
	This is the optimal solution - it applies the concept of the container to data, the nouns of software, instead of just to actions or verbs.		This is the optimal solution - it applies the concept of the container to data, the nouns of software, instead of just to actions or verbs.

	Here is an example ~~use-case~~: ~~you have a postgres database file that~~ you want to ~~make accessible to~~ a bunch of ~~arbitrary postgres containers~~. Start by creating a ~~container that will hold your~~ data, and ~~make sure you~~ add a ~~persistent data volume to it~~:		Here is an example: let's say you want to share some data between a whole bunch of ubuntu machines. Start by creating a new ubuntu machine with a persistent data volume at <code>/data</code>, and create some data there (we'll add a flag):

	<pre>		<pre>
	$ docker ~~create~~ -v /~~dbdata~~ --name ~~dbstore training~~/~~postgres~~ /bin/~~true~~		$ docker run -v /data --name ctf -it ubuntu
			root@b426841907f7:/# echo $SHELL
			/bin/bash
			root@b426841907f7:/# echo "The flag is 2aae6c35c94fcfb415dbe95f408b9ce91ee846ed" > /data/flag.txt
			root@b426841907f7:/# exit
	</pre>		</pre>

	Now ~~you~~ can ~~run this Docker, optionally adding a local host directory to pass through to the container so you can copy data from the host system onto~~ the ~~persistent~~ <code>/~~dbdata~~</code> ~~volume. Once you're finished, the contents of the data volume will persist.~~		Now we can create other ubuntu docker containers and mount the <code>/data</code> directory in those containers:

	~~Now you can create new postgres containers, and tell them to mount the new~~ data ~~container's volume, containing the database file~~.		<pre>
			$ docker run --volumes-from ctf --name ctfclone1 -it ubuntu
			root@5bc1c9f61aec:/# cat /data/flag.txt
			The flag is 2aae6c35c94fcfb415dbe95f408b9ce91ee846ed
			root@5bc1c9f61aec:/#

			$ docker run --volumes-from ctf --name ctfclone2 -it ubuntu
			root@e2072bdf7926:/# cat /data/flag.txt
			The flag is 2aae6c35c94fcfb415dbe95f408b9ce91ee846ed
			root@e2072bdf7926:/#
			</pre>

			etc...

	==Using Host Directory for Data==		==Using Host Directory for Data==

Admin: /* Data Volumes */

2017-03-25T03:42:55Z

Data Volumes

← Older revision		Revision as of 03:42, 25 March 2017
Line 76:		Line 76:
	The first approach scales better; the second is good for one-off Docker container solutions.		The first approach scales better; the second is good for one-off Docker container solutions.

	==Data ~~Volumes~~==		==Making a New Data Volume==

	{{Quote\|		{{Quote\|
Line 97:		Line 97:

	This would spin up a Python docker container that runs hello_files.py with a filesystem at <code>/mydata</code>.		This would spin up a Python docker container that runs hello_files.py with a filesystem at <code>/mydata</code>.

			==Mounting a Data Volume Container==

			This is the optimal solution - it applies the concept of the container to data, the nouns of software, instead of just to actions or verbs.

			Here is an example use-case: you have a postgres database file that you want to make accessible to a bunch of arbitrary postgres containers. Start by creating a container that will hold your data, and make sure you add a persistent data volume to it:

			<pre>
			$ docker create -v /dbdata --name dbstore training/postgres /bin/true
			</pre>

			Now you can run this Docker, optionally adding a local host directory to pass through to the container so you can copy data from the host system onto the persistent <code>/dbdata</code> volume. Once you're finished, the contents of the data volume will persist.

			Now you can create new postgres containers, and tell them to mount the new data container's volume, containing the database file.

	==Using Host Directory for Data==		==Using Host Directory for Data==

Admin: /* Patterns */

2017-03-25T03:34:09Z

Patterns

@@ Line 66: / Line 66: @@
 </pre>
-=Patterns=
+=Volumes with Data=
-This section covers some patterns for organizing files so that you can move things in and out from containers, while also keeping in line with the philosophy behind docker containers, which is that they should be stateless.
+==Data Volumes==
 {{Quote|
@@ Line 79: / Line 87: @@
 [https://docs.docker.com/engine/tutorials/dockervolumes/ Docker Volumes tutorial]
 }}
 =Flags=
 {{DockerFlag}}

Admin: /* Mounting Read-Only Directories */

2017-03-25T03:21:57Z

Mounting Read-Only Directories

@@ Line 34: / Line 34: @@
 This starts a docker container with the name "pwd", and mounts the current working directory (say, <code>/home/someone/docker</code>) to the same path in the docker image <code>/home/someone/docker</code>. It then sets the working directory to that directory.
-==Mounting Read-Only Directories==
+==Making Container Filesystem Read-Only==
 Read only control can be set on volumes as well: <code>--read-only</code> flag. This flag makes the entire contents of the container's root filesystem read-only, except for volumes mounted with the <code>-v</code> flag. To illustrate:
@@ Line 47: / Line 47: @@
 $ # no error, no poblem!
 </pre>

Admin: /* Patterns */

2017-03-25T03:13:41Z

Patterns

← Older revision		Revision as of 03:13, 25 March 2017
Line 53:		Line 53:
	This section covers some patterns for organizing files so that you can move things in and out from containers, while also keeping in line with the philosophy behind docker containers, which is that they should be stateless.		This section covers some patterns for organizing files so that you can move things in and out from containers, while also keeping in line with the philosophy behind docker containers, which is that they should be stateless.

			{{Quote\|
			A data volume is a specially-designated directory within one or more containers that bypasses the Union File System to provide several useful features for persistent or shared data:

			* Data volumes can be shared and reused between containers
			* Changes to a data volume are made directly
			* Changes to a data volume will not be included when you update an image

			[https://docs.docker.com/engine/tutorials/dockervolumes/ Docker Volumes tutorial]
			}}

	=Flags=		=Flags=

	{{DockerFlag}}		{{DockerFlag}}

Admin: /* Mounting Read-Only Directories */

2017-03-25T02:52:34Z

Mounting Read-Only Directories

← Older revision		Revision as of 02:52, 25 March 2017
Line 36:		Line 36:
	==Mounting Read-Only Directories==		==Mounting Read-Only Directories==

			Read only control can be set on volumes as well: <code>--read-only</code> flag. This flag makes the entire contents of the container's root filesystem read-only, except for volumes mounted with the <code>-v</code> flag. To illustrate:

			<pre>
			$ # this will not work, because /canttouchthis is part of the container's root filesystem
			$ docker run -t --read-only -v /icanwrite busybox touch /canttouchthis
			touch: /canttouchthis: Read-only file system

			$ # this will work, because /icanwrite is mounted with -v and is not read-only
			$ docker run --read-only -v /icanwrite busybox touch /icanwrite/here

			$ # no error, no poblem!
			</pre>

	=Patterns=		=Patterns=

Admin: /* Mounting Host Folders */

2017-03-25T02:46:44Z

Mounting Host Folders

← Older revision		Revision as of 02:46, 25 March 2017
Line 33:		Line 33:

	This starts a docker container with the name "pwd", and mounts the current working directory (say, <code>/home/someone/docker</code>) to the same path in the docker image <code>/home/someone/docker</code>. It then sets the working directory to that directory.		This starts a docker container with the name "pwd", and mounts the current working directory (say, <code>/home/someone/docker</code>) to the same path in the docker image <code>/home/someone/docker</code>. It then sets the working directory to that directory.

			==Mounting Read-Only Directories==


			=Patterns=

			This section covers some patterns for organizing files so that you can move things in and out from containers, while also keeping in line with the philosophy behind docker containers, which is that they should be stateless.


			=Flags=

			{{DockerFlag}}

Admin: Created page with "=Basics= ==Working Directory== First, we can set the working directory when we run a container by using the -w flag:

 $ docker  run -w /path/to/dir/ -i -t  ubuntu pwd..."

2017-03-25T02:45:29Z

Created page with "=Basics= ==Working Directory== First, we can set the working directory when we run a container by using the -w flag: <pre> $ docker run -w /path/to/dir/ -i -t ubuntu pwd..."

New page

=Basics=

==Working Directory==

First, we can set the working directory when we run a container by using the -w flag:

<pre>
$ docker run -w /path/to/dir/ -i -t ubuntu pwd
</pre>

This starts a new ubuntu image called pwd with the current working directory (when it starts up) set to <code>/path/to/dir</code>.

==Setting Disk Space==

We can set the amount of storage for the docker container using --storage-opt flag:

<pre>
$ docker run -it --storage-opt size=120G fedora /bin/bash
</pre>

This starts a fedora image with a bash shell, and uses 120 gb for the container.

==Mounting Host Folders==

Can mount folders on the host machine to drives in the docker machine:

<pre>
$ docker run \
-v `pwd`:`pwd` \
-w `pwd` \
-i -t ubuntu pwd
</pre>

This starts a docker container with the name "pwd", and mounts the current working directory (say, <code>/home/someone/docker</code>) to the same path in the docker image <code>/home/someone/docker</code>. It then sets the working directory to that directory.