Comment 2 for bug 1646141

 cat /usr/lib/systemd/system/glean@.service
[Unit]
Description=Glean for interface %I
Before=network-pre.target
Wants=network-pre.target

ConditionPathExists=!/etc/sysconfig/network-scripts/ifcfg-%I

[Service]
Type=oneshot
User=root
ExecStartPre=/usr/local/bin/glean.sh %I
ExecStart=/sbin/ifup %I
RemainAfterExit=true

[Install]
WantedBy=multi-user.target