Comment 9 for bug 1775131

Ubuntu:
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.1 LTS
Release: 18.04
Codename: bionic

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root@u18_svr_madsz:/icxmSim/dist# ifconfig
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
        inet 10.206.49.229 netmask 255.255.255.0 broadcast 10.206.49.255
        inet6 fe80::20c:29ff:fe1e:a792 prefixlen 64 scopeid 0x20<link>
        ether 00:0c:29:1e:a7:92 txqueuelen 1000 (Ethernet)
        RX packets 3732692 bytes 539980595 (539.9 MB)
        RX errors 0 dropped 911281 overruns 0 frame 0
        TX packets 230447 bytes 18384025 (18.3 MB)
        TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

ens34: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
        inet 192.168.49.229 netmask 255.255.0.0 broadcast 192.168.255.255
        inet6 3001:10::49:229 prefixlen 64 scopeid 0x0<global>
        inet6 fe80::20c:29ff:fe1e:a79c prefixlen 64 scopeid 0x20<link>
        ether 00:0c:29:1e:a7:9c txqueuelen 1000 (Ethernet)
        RX packets 634317126 bytes 109589158528 (109.5 GB)
        RX errors 0 dropped 3113 overruns 0 frame 0
        TX packets 519166 bytes 50492097 (50.4 MB)
        TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

icx5: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
        inet6 fe80::6438:8fff:fed6:4a54 prefixlen 64 scopeid 0x20<link>
        ether 66:38:8f:d6:4a:54 txqueuelen 1000 (Ethernet)
        RX packets 1287609 bytes 78787666 (78.7 MB)
        RX errors 0 dropped 2805 overruns 0 frame 0
        TX packets 5 bytes 446 (446.0 B)
        TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
        inet 127.0.0.1 netmask 255.0.0.0
        inet6 ::1 prefixlen 128 scopeid 0x10<host>
        loop txqueuelen 1000 (Local Loopback)
        RX packets 1457 bytes 261910 (261.9 KB)
        RX errors 0 dropped 0 overruns 0 frame 0
        TX packets 1457 bytes 261910 (261.9 KB)
        TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

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Operation:
create 2 virtual interface of mac vlan type, as 2icx0, 2icx1,
always the last created interface is availble, older one get deleted due to

Apr 16 10:56:28 u18_svr_madsz networkd-dispatcher[824]: WARNING:Unknown index 72 seen, reloading interface list
Apr 16 10:56:28 u18_svr_madsz systemd-networkd[22168]: 2icx0: Lost carrier

Same feature macvlan work in 16.04

ip link add link ens34 2icx0 type macvlan
ifconfig 2icx0 up
ip addr add 192.168.49.230/16 dev 2icx0

ip link add link ens34 2icx1 type macvlan
ifconfig 2icx1 up
ip addr add 192.168.49.231/16 dev 2icx1

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syslog:
pr 16 10:56:27 u18_svr_madsz systemd-udevd[30948]: link_config: autonegotiation is unset or enabled, the speed and duplex are not writable.
Apr 16 10:56:27 u18_svr_madsz systemd-udevd[30948]: Could not generate persistent MAC address for 2icx0: No such file or directory
Apr 16 10:56:27 u18_svr_madsz systemd-networkd[22168]: 2icx0: Gained carrier
Apr 16 10:56:27 u18_svr_madsz networkd-dispatcher[824]: WARNING:Unknown index 71 seen, reloading interface list
Apr 16 10:56:27 u18_svr_madsz systemd-timesyncd[22214]: Network configuration changed, trying to establish connection.
Apr 16 10:56:27 u18_svr_madsz systemd-udevd[30960]: link_config: autonegotiation is unset or enabled, the speed and duplex are not writable.
Apr 16 10:56:27 u18_svr_madsz systemd-udevd[30960]: Could not generate persistent MAC address for 2icx1: No such file or directory
Apr 16 10:56:28 u18_svr_madsz systemd-networkd[22168]: 2icx1: Gained carrier
Apr 16 10:56:28 u18_svr_madsz networkd-dispatcher[824]: WARNING:Unknown index 72 seen, reloading interface list
Apr 16 10:56:28 u18_svr_madsz systemd-networkd[22168]: 2icx0: Lost carrier