CoreOS : when pulling large docker image of size greater than 4 GB

Question

docker pull myimagename

leads to:

/var/lib/docker/overlay/670c89b1815cc9e3e27441690e47042fc554e432472ed8507`4284a890db56da0/    : no space left on device

df -h :

╔══════════════════════════════════════════════════════╗
║ Filesystem      Size  Used Avail Use% Mounted on     ║
╠══════════════════════════════════════════════════════╣
║ devtmpfs        4.3G     0  4.3G   0% /dev           ║
║ tmpfs           4.4G     0  4.4G   0% /dev/shm       ║
║ tmpfs           4.4G   17M  4.3G   1% /run           ║
║ tmpfs           4.4G     0  4.4G   0% /sys/fs/cgroup ║
║ tmpfs           4.4G  3.0G  1.4G  70% /              ║
║ /dev/loop0      162M  162M     0 100% /usr           ║
║ tmpfs           4.4G  228K  4.4G   1% /tmp           ║
║ tmpfs           4.4G     0  4.4G   0% /media         ║
╚══════════════════════════════════════════════════════╝

I can understand that, this is a space issue. But does that mean I cannot work on docker images of big size (in this case its 4 GB). How do I handle this problem?

Solution already tried:

I am running CoreOS on virtualbox.I tried increasing the virtual disk image size (even to 75 GB) , but still getting the same error.

Answer 1

From the output of your df -h command it looks like you are running CoreOS Live ISO image. So entire OS is loaded in RAM from the ISO (CD) and that CoreOS is not installed on the disk.

See https://coreos.com/os/docs/latest/installing-to-disk.html on how to install CoreOS onto the disk (in most basic version of the installation you can execute coreos-install -d /dev/sda and CoreOS will be installed on sda, deleting all the data on the disk).

See output of df -h on my CoreOS installation:

Filesystem      Size  Used Avail Use% Mounted on
devtmpfs         16G     0   16G   0% /dev
tmpfs            16G     0   16G   0% /dev/shm
tmpfs            16G  1.9M   16G   1% /run
tmpfs            16G     0   16G   0% /sys/fs/cgroup
/dev/sda9       901G  588G  276G  69% /
/dev/sda4       985M  390M  545M  42% /usr
/dev/sda1       128M   58M   70M  46% /boot
tmpfs            16G     0   16G   0% /media
tmpfs            16G     0   16G   0% /tmp
/dev/sda6       108M   52K   99M   1% /usr/share/oem
/dev/md126p1    1.8T  591G  1.2T  34% /home

Notice that mounting points are read disks and not tmpfs as in your case.

Installing and running CoreOS from disk will solve your problem.

Edit:

If you have already installed CoreOS, you might be booting OS from the CD (ISO) you used to do installtion from. You need to change boot order or to remove CD (ISO), so CoreOS is booted from the disk you have installed it on.