I'm building some CentOS VM with VMWare, with no access to internet, so I've downloaded and made local repositories, including this one Then I have installed docker-engine.x86_64, and when starting the docker daemon, I get the following errors :
[root]# dockerd
DEBU[0000] docker group found. gid: 993
...
...
DEBU[0001] Error retrieving the next available loopback: open /dev/loop-control: no such device
ERRO[0001] **There are no more loopback devices available.**
ERRO[0001] [graphdriver] prior storage driver "devicemapper" failed: loopback attach failed
DEBU[0001] Cleaning up old mountid : start.
FATA[0001] Error starting daemon: error initializing graphdriver: loopback attach failed
After manually add the loop module which control loop device with this command :
insmod /lib/modules/3.10.0-327.36.2.el7.x86_64/kernel/drivers/block/loop.ko
The error changes to :
[graphdriver] prior storage driver "devicemapper" failed: devicemapper: Error running deviceCreate (CreatePool) dm_task_run failed
I've read that it could be because I have not enough space disk, I think it's not that, any idea?
[root]# df -k .
Filesystem blocs de 1K Used Available Used Mounted on
/dev/mapper/centos-root 51887356 2436256 49451100 5% /
I got the "There are no more loopback devices available" error, which stopped dockerd from running.
I fixed it by ensuring the storage driver was 'overlay':
# /usr/bin/dockerd -D --storage-driver=overlay
This was on Debian Jessie and docker running as a systemd service/unit.
To make it permanent, I created a systemd drop-in:
$ cat /etc/systemd/system/docker.service.d/docker.conf
[Service]
ExecStart=
ExecStart=/usr/bin/dockerd -H fd:// --storage-driver=overlay