Docker Data generated by the container , If you do not back up , After the container instance is deleted , Naturally, there is no data in the container . In order to save data in docker We use volumes in .
characteristic ：
1： Data volumes can share or reuse data between containers
2： Changes in the volume can take effect directly in real time
3： Changes in the data volume are not included in the update of the mirror
4： The life cycle of a data volume lasts until no container uses it
Mount command ：
# docker run -it --privileged=true -v / Host absolute directory :/ Absolute directory in container Container name docker run -it
--privileged=true -v /tmp/my_dir:/tmp/docker_dir ubuntu /bin/bash
After mounting , have access to
docker inspect container ID
View the information in the container , find "Mount" node
{ ... "Mounts": [{ { "Type": "bind", // Absolute directory of the host "Source": "/tmp/my_dir", //
Absolute directory in container "Destination": "/tmp/docker_dir", "Mode": "", "RW": true,
"Propagation": "rprivate" } ] ... }
When container stop after , Continue to update files under the directory in the host machine , When the container again start Then you can see the updated file .
be careful ： When multiple containers mount the directory of the same host , Then these containers can read and write files under the directory of the host .
Read write rules ：ro and rw
The mounted directory is for the container directory , Default is RW（ Read only write only ） Permissions for , The following commands are used to control the read and write rules ：
# Set the read-only write permission of the container directory docker run -it -privileged=true -v
/tmp/my_dir:/tmp/docker_dir:rw ubuntu /bin/bash # Set container directory read-only permission docker run -it
-privileged=true -v /tmp/my_dir:/tmp/docker_dir:ro ubuntu /bin/bash #
If set ro jurisdiction , When updating files in the container directory , Will prompt ：touch: cannot touch 'd.txt': Read-only file system
Volume inheritance and sharing ：--volumes-from
# Create the first container docker run -it --privileged=true --name do1 -v
/tmp/my_dir:/tmp/docker_dir ubuntu /bin/bash # When creating the second container , Inherit the volume rule of the first container , format ： #
docker run -it --volumes-from Parent class container name ubuntu /bin/bash docker run -it
--privileged=true --name do2 --volumes-from do1 ubuntu /bin/bash
In this way, the second container also has the same host directory mount point as the first container .
Technology
Daily Recommendation