Comment # 4 on bug 903854 from Marius Tomaschewski

It would be probably helpful to attach the logs (/var/log/NetworkManager),
probably with NETCONFIG_VERBOSE=yes in /etc/sysconfig/network/config.

Please attach also the outputs of:

grep ^NETCONFIG /etc/sysconfig/network/config
netconfig update -v

A call to:

/sbin/netconfig modify -s NetworkManager <<EOF
DNSSEARCH='example.net example.com'
DNSDOMAIN='example.net'
DNSSERVERS='192.168.0.10 192.168.0.20'
EOF

works fine for me, the settings are written properly as needed.

Make sure that network.service points to NetworkManager (enabled via
"systemctl enable NetworkManager.service", see also yast2 bug 895447).