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  • Issue with Bonding - Device ethX has a different MAC address than expected

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    I’m encountering an issue while restarting/activating the network service with bonded interfaces on a RHEL 6.6 server. Details below:

    • The bonded interface and the slaves (active and backup) come up without any issues during system reboots. However, if the network service is restarted or if one of the interface went/brought down and is brought back, the backup slave does not come up – the error is: device ethX has a different MAC address than expected…ignoring
    • If I remove the HWADDR directive from the interface configuration files of the slaves, then this issue does not occur. However, the RedHat documentation mandates that the HWADDR directive be included in the interface configuration files if more than one NIC is present in the host. (the BL660c Gen8 has 16 interfaces btw).
    • The udev rules are in place and match with the interface configuration files.
    • I’ve already gone through the steps in https://access.redhat.com/solutions/223433 except for contacting the vendor

    Could you please advise how I can go about this?

    Sample config files:

    == Ifcfg-bondX==
    DEVICE=bondX
    IPADDR=x.x.x.x
    NETMASK=x.x.x.x
    ONBOOT=yes
    BOOTPROTO=none
    USERCTL=no
    NM_CONTROLLED=no
    BONDING_OPTS=”mode=1 miimon=100”

    == Ifcfg-ethX ==
    DEVICE=ethX
    BOOTPROTO=none
    ONBOOT=yes
    NM_CONTROLLED=no
    USERCTL=no
    HWADDR=x.x.x.x.x.x
    UUID=x.x.x.x..x.x.x.x.x.x
    MASTER=bondX
    SLAVE=yes

    I've reviewed this article as well: https://access.redhat.com/solutions/336513

    The article requires you to replace the HWADDR suggested by ‘ip a show ethX’ output. In reality, this MAC address is from the Primary/Active Slave interface. AFAIK, the bondX interface chooses the MAC address of the Primary interface (among the bonded interfaces) and assigns/expects the same to secondary/backup slave interface to avoid packet drops during failover.

    When I checked the contents of /sys/class/net/eth{1,8}/address, I see that both have the same MAC address.

    My concern is:
    - Can you activate successfully two interfaces with the same MAC addresses???
    - Can we remove HWADDR from the slave interface configuration files? will that have any other impact?

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