====== Volumes ======
[[https://docs.docker.com/engine/tutorials/dockervolumes/]]

  Data volumes are designed to persist data, independent of the container’s life cycle. Docker therefore never automatically delete volumes when you remove a container, nor will it “garbage collect”     volumes that are no longer referenced by a container.
  A Docker data volume persists after a container is deleted.


Volumes types:
  * Anonymous Volume: any volume without a source, docker will create this as a local volume with a long unique id, and it behaves as a named volume
  * Named Volume - local storage (original image data located in specified directory are copied to volume during creation)
    * **local** driver is using ''/var/lib/docker/volumes'' for storage
    * original image data **is copied** if volume is empty. 
    * All UID/GIDs are correctly set
    * user has to take care about free space at ''/var/lib/docker/volumes''
  * Host volume: bind-mounted host
    * original image data are **not copied**
    * fastest - no volume driver is used
    * possible problem with UID/GID permisions
    * volume can be created on any location (different discs, etc)
  * volume plugins

Move volume between discs:
<code bash>rsync -aqxP jenkins1_jenkins_homeSNAP/ /mnt/NVMe/@jenkins1_jenkins_home</code>

===== BTRFS Volume plugin for Docker =====
[[https://github.com/anybox/buttervolume]]


Volume destination inside container must be a absolute path.

Run shell with mounted volume from another docker:
<code bash>docker run --rm -i --volumes-from dbdata busybox ash</code>
<code bash>docker run --rm -i --volumes-from dbdata debian:jessie-slim /bin/bash</code>

Single file can be mounted as volume:
<code bash>docker run --rm -it -v ~/.bash_history:/root/.bash_history debian:jessie-slim bash /bin/bash</code>

Create named volume and share it between multiple containers:
<code bash>
docker run -d -P -v my-named-volume:/opt --name test1 debian:jessie-slim bash
docker run -d -P -v my-named-volume:/opt --name test2 debian:jessie-slim bash
docker run -d -P -v my-named-volume:/opt --name test3 debian:jessie-slim bash
</code>

To protect data from being deleted with volume use ''local-persist'' plugin: [[https://github.com/CWSpear/local-persist]]

Find orphaned volumes
<code bash>
docker volume ls -f dangling=true
docker volume rm <volume name>
</code>

Transfer volume to another host [[https://www.guidodiepen.nl/2016/05/transfer-docker-data-volume-to-another-host/]]

[[https://github.com/gdiepen/docker-convenience-scripts/blob/master/docker_get_data_volume_info.sh]]

====== data persistence in swarm ======
[[http://mysqlrelease.com/2016/08/trying-out-mysql-in-docker-swarm-mode/]]
[[https://forums.docker.com/t/data-base-persistence-in-docker-swarm-mode/20665/7]]