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--- docker:persistent_storage [2020/04/16 08:17] – created peter
+++ docker:persistent_storage [2020/05/13 08:48] (current) – removed peter
@@ Line 1: / Line 1: @@
-====== Docker - Persistent Storage ======
-<WRAP todo>
-TODO...
-</WRAP>
-The approach that seems to work best for production is to use a **data only container**.
-The data only container is run on a barebone image and actually does nothing except exposing a data volume.
-Then you can run any other container to have access to the data container volumes:
-<code bash>
-docker run --volumes-from data-container some-other-container command-to-execute
-</code>
-  * [[http://www.offermann.us/2013/12/tiny-docker-pieces-loosely-joined.html|Here]] you can get a good picture of how to arrange the different containers.
-  * [[http://crosbymichael.com/advanced-docker-volumes.html|Here]] there is a good insight on how volumes work.
-UPDATE:
-In [[http://container42.com/2013/12/16/persistent-volumes-with-docker-container-as-volume-pattern/|this blog post]] there is a good description of the so called **container as volume pattern** which clarifies the main point of having **data only containers**.
-UPDATE 2:
-[[https://docs.docker.com/engine/userguide/dockervolumes/|Docker documentation has now the DEFINITIVE description of the container as volume/s pattern]].
-UPDATE 3:
-Updated docs with backup/restore procedure
-BACKUP:
-<code bash>
-sudo docker run --rm --volumes-from DATA -v $(pwd):/backup busybox tar cvf /backup/backup.tar /data
-</code>
-  * --rm: remove the container when it exits
-  * --volumes-from DATA: attach to the volumes shared by the DATA container
-  * -v $(pwd):/backup: bind mount the current directory into the container; to write the tar file to
-  * busybox: a small simpler image - good for quick maintenance
-  * tar cvf /backup/backup.tar /data: creates an uncompressed tar file of all the files in the /data directory
-RESTORE:
-<code bash>
-# create a new data container
-$ sudo docker run -v /data -name DATA2 busybox true
-# untar the backup files into the new container᾿s data volume
-$ sudo docker run --rm --volumes-from DATA2 -v $(pwd):/backup busybox tar xvf /backup/backup.tar
-data/
-data/sven.txt
-# compare to the original container
-$ sudo docker run --rm --volumes-from DATA -v `pwd`:/backup busybox ls /data
-sven.txt
-</code>
-UPDATE 4
-A nice [[http://container42.com/2014/11/18/data-only-container-madness/|article from the excellent Brian Goff]] explaining why it is good to use the same image for a container and a data container.
-UPDATE 5
-Docker 1.9.0 has new volume API!
-<code bash>
-docker volume create --name hello
-docker run -d -v hello:/container/path/for/volume container_image my_command
-</code>
-this means that the data only container pattern must be abandoned in favour of the new volumes.
-Actually the volume API is only a better way to achieve what was the data-container pattern.
-If you create a container with a **-v volume_name:/container/fs/path** docker will automatically create a named volume for you that can:
-  - Be listed through the **docker volume ls**.
-  - Be identified through the **docker volume inspect volume_name**.
-  - Backed up as a normal dir.
-  - Backed up as before through a **<nowiki>--volumes-from</nowiki>** connection.
-The new volume api adds a useful command that let you identify dangling volumes:
-<code bash>
-docker volume ls -f dangling=true
-</code>
-And then remove it through its name:
-<code bash>
-docker volume rm <volume name>
-</code>
-----
-===== References =====
-http://stackoverflow.com/questions/18496940/how-to-deal-with-persistent-storage-e-g-databases-in-docker?rq=1
-http://txt.fliglio.com/2013/11/creating-a-mysql-docker-container/