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Last active October 4, 2018 23:48
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Some notes for docker in docker.
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docker.in.docker.md

Docker in docker implementation:

https://github.com/jpetazzo/dind

Issue:

docker pull consume tremendous amount of storage until no space left on device.

Check backing file system host docker is using with command docker info:

$ docker info
Storage Driver: overlay
 Backing Filesystem: xfs
 Supports d_type: true

On file system with support d_type: false, docker in docker (check docker info inside docker container) uses Storage Driver: vfs.

If host file system is XFS, we need d_type = true to ensure docker works fine using overlay file system. If not, we can either reformat host file system to support d_type = true, or simply change host docker storage location (default is /var/lib/docker). Be aware this will cause previously pulled docker images disappear. To do so, on CentOS, we need to:

sudo systemctl stop docker
ln -s <directory> /var/lib/docker
sudo systemctl start docker

The directory has to be on a file system that is XFS with d_type support. Or other file system such as ext4. Use command df -Th to see disks available.

References:

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