Docker engine failed to start

General
1

I am installing docker in cntos7 version aws Ec2 instance. But the docker Engine failed to start. How can I resolve the problem Please explain?

2

I am getting the same problem.
Centos 7, previously had docker engine which worked fine.
Followed docs in Install Docker Engine on CentOS | Docker Docs so latest version of docker-ce from repo.

sudo systemctl start docker
Job for docker.service failed because the control process exited with error code. See “systemctl status docker.service” and “journalctl -xe” for details.

sudo systemctl status docker.service
● docker.service - Docker Application Container Engine
Loaded: loaded (/etc/systemd/system/docker.service; disabled; vendor preset: disabled)
Active: failed (Result: exit-code) since Thu 2018-05-31 10:03:37 BST; 3min 32s ago
Docs: https://docs.docker.com
Process: 33801 ExecStart=/usr/bin/docker daemon -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock (code=exited, status=1/FAILURE)
Main PID: 33801 (code=exited, status=1/FAILURE)

May 31 10:03:37 centos7 systemd[1]: Starting Docker Application Container Engine…
May 31 10:03:37 centos7 docker[33801]: docker: ‘daemon’ is not a docker command.
May 31 10:03:37 centos7 docker[33801]: See ‘docker --help’
May 31 10:03:37 centos7 systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE
May 31 10:03:37 centos7 systemd[1]: Failed to start Docker Application Container Engine.
May 31 10:03:37 centos7 systemd[1]: Unit docker.service entered failed state.
May 31 10:03:37 centos7 systemd[1]: docker.service failed.

Having googled, have removed /var/lib/docker directory - no affect
Have created /etc/docker/daemon.json
{
“data-root”: “/mnt/docker-data”,
“storage-driver”: “overlay”
}
Again, no success.
The kernel is 3.10 - does this need to be upgraded?