Docker storage after kernel upgrade

I recently upgraded my linux kernel to 4.9.75, the latest 4.14 release gave me network related issues, on Ubuntu 16.04.2 after hearing about the Meltdown and Spectre security flaws and reading Greg Kroah-Hartman’s blog.

Upgrading the kernel

$ cd /tmp/
$ wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.9.75/linux-headers-4.9.75-040975-generic_4.9.75-040975.201801051530_amd64.deb
$ wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.9.75/linux-image-4.9.75-040975-generic_4.9.75-040975.201801051530_amd64.deb
$ wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.9.75/linux-headers-4.9.75-040975_4.9.75-040975.201801051530_all.deb
$ sudo dpkg -i \*.deb
$ sudo update-grub
$ sudo reboot

Bob was my uncle until I had to get on with my daily development workflow which makes heavy use of docker. I got an error that pointed to storage driver \"aufs\" failed: driver not supported.

After some digging, I found that for aufs one has to install, depending on the distribution, linux-image-extra. However, only the kernel version that ships with the distribution is officially supported. I then discovered that overlay2 is recommended for kernel v4.0 and higher.

Changing the storage driver

NOTE: You will lose access to all your current images and containers due to layers! Reverting your changes will make your old images and containers accessible again. You can use

$ docker save IMAGE:TAG > IMAGE.tar.gz

to save your current images, and

$ docker load < IMAGE.tar.gz

to import them on the new storage driver.

Stop docker:

$ sudo systemctl stop docker

Edit the file /etc/docker/daemon.json (create it if doesn’t exist) and add the following to the file:

{
  "storage-driver": "overlay2"
}

Start docker:

$ sudo systemctl start docker

Use docker info to verify that the storage driver is being used:

$ docker info
...
Storage Driver: overlay2
...

Hope someone out there finds this helpful.