hostnamectl

# works as expected

core@coreos-1 ~ $ sudo hostnamectl set-hostname 'coreos-1.banteng.be'
core@coreos-1 ~ $ hostnamectl
   Static hostname: coreos-1.banteng.be
         Icon name: computer-vm
           Chassis: vm
        Machine ID: fcb997ab81144cdd8486ebed3da426bd
           Boot ID: 7f40717efbe34fdbbc1d3efff6141d71
    Virtualization: kvm
  Operating System: CoreOS 723.3.0
            Kernel: Linux 4.0.5
      Architecture: x86-64

# will omit trailing dot for static hostname (as it's invalied)

core@coreos-1 ~ $ sudo hostnamectl set-hostname 'coreos-1.banteng.be.'
core@coreos-1 ~ $ hostnamectl
   Static hostname: coreos-1.banteng.be
   Pretty hostname: coreos-1.banteng.be.
         Icon name: computer-vm
           Chassis: vm
        Machine ID: fcb997ab81144cdd8486ebed3da426bd
           Boot ID: 7f40717efbe34fdbbc1d3efff6141d71
    Virtualization: kvm
  Operating System: CoreOS 723.3.0
            Kernel: Linux 4.0.5
      Architecture: x86-64

# setting it specifically for static or pretty
# (new node so transient is still set)

core@coreos-1 ~ $ sudo hostnamectl set-hostname --static coreos-1.banteng.be
core@coreos-1 ~ $ hostnamectl
   Static hostname: coreos-1.banteng.be
Transient hostname: coreos-1
         Icon name: computer-vm
           Chassis: vm
        Machine ID: fcb997ab81144cdd8486ebed3da426bd
           Boot ID: 7f40717efbe34fdbbc1d3efff6141d71
    Virtualization: kvm
  Operating System: CoreOS 723.3.0
            Kernel: Linux 4.0.5
      Architecture: x86-64
core@coreos-1 ~ $ sudo hostnamectl set-hostname --static coreos-1.banteng.be.
Could not set property: Invalid static hostname 'coreos-1.banteng.be.'
core@coreos-1 ~ $ sudo hostnamectl set-hostname --pretty coreos-1.banteng.be.
core@coreos-1 ~ $ hostnamectl
   Static hostname: coreos-1.banteng.be
   Pretty hostname: coreos-1.banteng.be.
Transient hostname: coreos-1
         Icon name: computer-vm
           Chassis: vm
        Machine ID: fcb997ab81144cdd8486ebed3da426bd
           Boot ID: 7f40717efbe34fdbbc1d3efff6141d71
    Virtualization: kvm
  Operating System: CoreOS 723.3.0
            Kernel: Linux 4.0.5
      Architecture: x86-64
core@coreos-1 ~ $ sudo hostnamectl set-hostname --pretty 'coreos-1.banteng.be. whatever'
core@coreos-1 ~ $ hostnamectl
   Static hostname: coreos-1.banteng.be
   Pretty hostname: coreos-1.banteng.be. whatever
Transient hostname: coreos-1
         Icon name: computer-vm
           Chassis: vm
        Machine ID: fcb997ab81144cdd8486ebed3da426bd
           Boot ID: 7f40717efbe34fdbbc1d3efff6141d71
    Virtualization: kvm
  Operating System: CoreOS 723.3.0
            Kernel: Linux 4.0.5
      Architecture: x86-64