Change Details

## Summary Adding a second member interface to an existing bond re-assigns the bond's MAC address to that new member. The bond changes its identity on the wire, breaking ARP/ND and LACP for peers that already learned it. ## Steps to reproduce ``` set interfaces bonding bond0 mode 802.3ad set interfaces bonding bond0 member interface eth1 commit run show interfaces bonding bond0 # note link/ether of bond0 run show interfaces bonding bond0 slaves Interface RX: bytes packets TX: bytes packets bond0 0 0 0 0 eth1 0 0 0 0 ``` ``` set interfaces bonding bond0 member interface eth2 commit run show interfaces bonding bond0 # link/ether is now eth2's MAC run show interfaces bonding bond0 slaves Interface RX: bytes packets TX: bytes packets bond0 0 0 0 0 eth2 0 0 0 0 ``` ## Actual bond0 and eth2 share aa:c1:ab:c3:62:48; the address the bond had from eth1 is gone. ## Expected bond0 keeps the MAC it adopted at creation time. Appending a member must not change it. T7571 made the bond adopt its first member's MAC, since newer kernels assign a synthetic one. In BondIf.update() the driving flag is initialised True unconditionally, and an already enslaved member hits continue without clearing it, so the adoption re-runs on every append.

## Summary Adding a second member interface to an existing bond re-assigns the bond's MAC address to that new member. The bond changes its identity on the wire, breaking ARP/ND and LACP for peers that already learned it. ## Steps to reproduce ``` set interfaces bonding bond0 mode 802.3ad set interfaces bonding bond0 member interface eth1 commit run show interfaces bonding bond0 # note link/ether of bond0 run show interfaces bonding bond0 slaves Interface RX: bytes packets TX: bytes packets bond0 0 0 0 0 eth1 0 0 0 0 ``` ``` set interfaces bonding bond0 member interface eth2 commit run show interfaces bonding bond0 # link/ether is now eth2's MAC run show interfaces bonding bond0 slaves Interface RX: bytes packets TX: bytes packets bond0 0 0 0 0 eth2 0 0 0 0 ``` ## Actual `bond0` and `eth2` share `aa:c1:ab:c3:62:48`; the address the bond had from `eth1` is gone. If both bond members are added simultanously, no issue exists. ## Expected `bond0` keeps the MAC it adopted at creation time. Appending a member must not change it, nor remove it from the slave list. T7571 made the bond adopt its first member's MAC, since newer kernels assign a synthetic one. In `BondIf.update()` the driving flag is initialised `True` unconditionally, and an already enslaved member hits continue without clearing it, so the adoption re-runs on every append.

## Summary Adding a second member interface to an existing bond re-assigns the bond's MAC address to that new member. The bond changes its identity on the wire, breaking ARP/ND and LACP for peers that already learned it. ## Steps to reproduce ``` set interfaces bonding bond0 mode 802.3ad set interfaces bonding bond0 member interface eth1 commit run show interfaces bonding bond0 # note link/ether of bond0 run show interfaces bonding bond0 slaves Interface RX: bytes packets TX: bytes packets bond0 0 0 0 0 eth1 0 0 0 0 ``` ``` set interfaces bonding bond0 member interface eth2 commit run show interfaces bonding bond0 # link/ether is now eth2's MAC run show interfaces bonding bond0 slaves Interface RX: bytes packets TX: bytes packets bond0 0 0 0 0 eth2 0 0 0 0 ``` ## Actual bond0 and eth2 share aa:c1:ab:c3:62:48;`bond0` and `eth2` share `aa:c1:ab:c3:62:48`; the address the bond had from `eth1` is gone. If both bond members are added simultanously, the address the bond had from eth1 is goneno issue exists. ## Expected `bond0` keeps the MAC it adopted at creation time. Appending a member must not change it, Appending a member must not change itnor remove it from the slave list. T7571 made the bond adopt its first member's MAC, since newer kernels assign a synthetic one. In In `BondIf.update()` the driving flag is initialised `True` unconditionally, and an already enslaved member hits continue without clearing it, so the adoption re-runs on every append.