it helps some times Docker doesn't do virtualization. It uses kernel namespaces to achieve a chroot-like effect not just for the root filesystem but process information (PID namespace), mount points, networking, IPC (shared memory), UTS information (hostname) & user id's. The containers share the kernel with the host. For security Docker uses AppArmor/SELinux, Linux capabilities and seccomp to filter system calls. Control groups (known as cgroups] are used for process accounting and for imposing limits on resources.
I hope this helps you . If your intention is to take multiple machines and make them look like one computing unit, you could look at putting them all under an orchestration software like Kubernetes, Mesos or Docker Swarm. All of these orchestrators run docker containers.
Does docker use virtualization solution when running in linux machines?
I wish this helpful for you First, why hyper-v? The reason for docker on windows using hyper-v VM just because: for a linux container, it had to share the linux kernel of host. But on windows, we do not have linux kernel, so docker set a hyper-v VM for you, then let your container to share the kernel.
Is Docker Toolbox or Docker for Mac beneficial over virtualization solutions?