How can i attach a HBA card (which is on my physical server running on centos 7) to a docker container? As I'm doing POC for migration to docker from existing environment this is much needed. It's similar to direct IO in VMware ESXi(Attaching a physical hba to VM can be done via Direct I/O).
Docker isn't a hypervisor, containers aren't VMs, and "attaching devices" to a container doesn't necessarily make sense -- a container is just a process running on your host.
You can expose a device node in /dev to a container using the --device flag to docker run, although exposing a block device inside a container usually leads to other complications (e.g., a normal container can't mount filesystems, so you would need to run it with --privileged, which may or may not be acceptable form a security perspective depending on your environment).
For storage, it is more common to mount devices on the host, and then expose those filesystems to container as Docker volumes (-v /host/path:/container/path).