For our backups to work on Linux servers in Hyper-V, the hypervvssd.service needs to be running. Linux Integration Services are included by default in CentOS 7. However, the daemon tools are not installed.

# Install Hyper-V Daemons
$ sudo yum install hyperv-daemons

# This will also install the following dependancies:
 Package                                                    Arch                                       Version                                                      Repository                                Size
 hyperv-daemons                                             x86_64                                     0-0.34.20180415git.el7                                       base                                     5.3 k
Installing for dependencies:
 hyperv-daemons-license                                     noarch                                     0-0.34.20180415git.el7                                       base                                      13 k
 hypervfcopyd                                               x86_64                                     0-0.34.20180415git.el7                                       base                                      11 k
 hypervkvpd                                                 x86_64                                     0-0.34.20180415git.el7                                       base                                      20 k
 hypervvssd                                                 x86_64                                     0-0.34.20180415git.el7                                       base                                      13 k

# Reboot
$ sudo shutdown -r now

# Confirm services are running
$ systemctl | grep hyperv
hypervkvpd.service                                                    loaded active running   Hyper-V KVP daemon
hypervvssd.service                                                    loaded active running   Hyper-V VSS daemon

That's it. It's worth noting that this is using the inbuilt LIS package. A more up-to-date package is available from Microsoft. However, it isn't required. Further information for Microsoft is available here.