How do I change devicemapper to overlay2?
Complete the following steps to migrate device mapper to overlay2 on your worker nodes.
- Log in to the worker node as the root user.
- Check your current storage driver.
- If the node uses the device mapper as a storage controller, you must log in to the CDF administration portal.
Table of Contents
How do I change the default docker storage driver?
Configure Docker with the overlay or overlay2 storage driver
- Stop Docker.
- Copy the contents of /var/lib/docker to a temporary location.
- If you want to use a separate backup filesystem from the one used by /var/lib/ , format the filesystem and mount it to /var/lib/docker .
- Edit /etc/docker/daemon.
- Start Docker.
How do I clear my overlay cache?
- Drain the docker instance from the ELB.
- shutdown docker systemctl stop docker rm -rf /var/lib/docker/overlay/*
- Run the results of the commands for d in $(find /var/lib/docker/image/overlay -type d -name ‘*sha256*’); do echo rm -rf $d/* ; done.
- reboot (easiest way to get everything back)
What is the docker command to view the storage driver docker you are currently using?
To see which storage controller Docker is currently using, use the Docker information and look for the Storage Controller line: To change the storage controller, see the specific instructions for the new storage controller. Some controllers require additional configuration, including setting up physical or logical disks on the Docker host.
What is overlap in DF?
Built into the mainline Linux kernel with version 3.18, OverlayFS allows you to overlay the contents (both files and directories) of one directory onto another. We can think of them as “top” and “bottom”, with the rest of Linux and applications positioned above that. The “bottom” directory is read-only.
How to use OverlayFS storage driver in Docker?
To see the mounts that exist when you use the overlay storage driver with Docker, use the mount command. The following result is truncated for readability. The rw on the second line shows that the overlay mount is read/write. This content applies only to the overlay controller. Docker recommends using the overlay2 driver, which works differently.
How does the device mapper driver work in Docker?
The device mapper driver uses Docker-dedicated block devices and operates at the block level, rather than the file level. These devices can be expanded by adding physical storage to your Docker host and work better than using a file system at the operating system (OS) level.
What happens when you change the storage driver in Docker?
Changing the storage driver makes existing containers and images inaccessible on the local system. Use docker save to save the images you’ve built, or push them to Docker Hub or a private registry before you change the storage controller, so you don’t have to rebuild them later.
How to resize Docker containers with device mapper?
Delete /var/lib/docker. Warning: as mentioned above, this will delete all your containers, all your images. Create the storage directory: mkdir -p /var/lib/docker/devicemapper/devicemapper. Create your pool: dd if=/dev/zero of=/var/lib/docker/devicemapper/devicemapper/data bs=1G count=0 seek=250 will create a 250G sparse file.