#ifup bond0
/etc/network/if-pre-up.d/ifenslave: 39: echo: echo: I/O error
/etc/network/if-pre-up.d/ifenslave: 39: echo: echo: I/O error
RTNETLINK answers: File exists
ifup: failed to bring up bond0


# ifup -v bond0

ifup: configuring interface bond0=bond0 (inet)
run-parts --exit-on-error --verbose /etc/network/if-pre-up.d
run-parts: executing /etc/network/if-pre-up.d/ethtool
run-parts: executing /etc/network/if-pre-up.d/ifenslave
+ [ inet = meta ]
+ IF_BOND_SLAVES=lan0 lan1
+ [ -n  ]
+ [ -n lan0 lan1 ]
+ BOND_MASTER=bond0
+ BOND_SLAVES=lan0 lan1
+ setup_master_device bond0
+ add_master
+ [ -f /sys/class/net/bond0/bonding/slaves ]
+ return
+ early_setup_master
+ sysfs fail_over_mac
+ [ -n  ]
+ return 0
+ setup_master
+ sysfs use_carrier
+ [ -n  ]
+ return 0
+ sysfs num_grat_arp
+ [ -n  ]
+ return 0
+ sysfs num_unsol_na
+ [ -n  ]
+ return 0
+ sysfs_add arp_ip_target
+ sysfs arp_interval
+ [ -n  ]
+ return 0
+ sysfs miimon 100
+ [ -n 100 ]
+ echo 100
+ return 0
+ sysfs downdelay 200
+ [ -n 200 ]
+ echo 200
+ return 0
+ sysfs updelay 200
+ [ -n 200 ]
+ echo 200
+ return 0
+ sysfs_change_down ad_select
+ [ -n  ]
+ sysfs_change_down mode 4
+ [ -n 4 ]
+ grep -sq \<4\> /sys/class/net/bond0/bonding/mode
+ sysfs mode 4
+ [ -n 4 ]
+ echo 4
/etc/network/if-pre-up.d/ifenslave: 39: echo: echo: I/O error
+ return 1
+ sysfs_change_down xmit_hash_policy layer3+4
+ [ -n layer3+4 ]
+ grep -sq \<layer3+4\> /sys/class/net/bond0/bonding/xmit_hash_policy
+ sysfs xmit_hash_policy layer3+4
+ [ -n layer3+4 ]
+ echo layer3+4
+ return 0
+ sysfs_change_down tlb_dynamic_lb
+ [ -n  ]
+ sysfs packets_per_slave
+ [ -n  ]
+ return 0
+ sysfs arp_validate
+ [ -n  ]
+ return 0
+ sysfs_change_down lacp_rate 1
+ [ -n 1 ]
+ grep -sq \<1\> /sys/class/net/bond0/bonding/lacp_rate
+ sysfs lacp_rate 1
+ [ -n 1 ]
+ echo 1
/etc/network/if-pre-up.d/ifenslave: 39: echo: echo: I/O error
+ return 1
+ [ -n  ]
+ enslave_slaves
+ [ 1 = 1 ]
+ v=-v
+ export IFENSLAVE_ENV_NAME=IFUPDOWN_lan0
+ printenv IFUPDOWN_lan0
+ IFUPDOWN_IFACE=
+ unset IFENSLAVE_ENV_NAME
+ ifquery --state lan0
+ [ -n  ]
+ ip link set lan0 down
+ sysfs_add slaves lan0
+ ifup -v --allow bond0 lan0
+ export IFENSLAVE_ENV_NAME=IFUPDOWN_lan1
+ printenv IFUPDOWN_lan1
+ IFUPDOWN_IFACE=
+ unset IFENSLAVE_ENV_NAME
+ ifquery --state lan1
+ [ -n  ]
+ ip link set lan1 down
+ sysfs_add slaves lan1
+ ifup -v --allow bond0 lan1
+ setup_primary
+ sysfs primary_reselect
+ [ -n  ]
+ return 0
+ exit 0
ip addr add 192.168.10.102/255.255.255.0 broadcast 192.168.10.255 	  dev bond0 label bond0
RTNETLINK answers: File exists
ifup: failed to bring up bond0