9.2.1. Is the docker daemon running?
[root@localhost ~]# docker images
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
[root@localhost ~]# sudo systemctl start docker
[root@localhost ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ifkeeper/jvm8 v1.0.0 9ef7f38f2bf1 18 hours ago 583MB
jvm8 v1.0.0 9ef7f38f2bf1 18 hours ago 583MB
ifkeeper/centos-jvm8 v1.0.0 e15334134272 37 hours ago 583MB
centos latest 1e1148e4cc2c 4 days ago 202MB
openjdk latest 8e7eacedab93 5 days ago 986MB