VxRack: Management switch is not responding


   Article Number:     532247                                   Article Version: 2     Article Type:    Break Fix 




VxRack SDDC 14G-1





Dell S3048-ON management switch  is not responding. Cumulus software 3.3 or above is installed on this switch.   
    Switch had been just installed as part of a new rack expansion and after a soft reboot customer was unable to connect back to it.   
    The management switch is unreachable via IP address from virtual machines or hosts   






By default, Cumulus 3.3 and later reserves 1000 VLANs in the range of 3000-3999 to accommodate internal data plane operations. If VLANs have been defined in this range for any of the workload domains, networking issues will occur when attempting to communicate with the management switch from any of the VLANs that overlap from this range.                                                           












See also VMware KB https://kb.vmware.com/s/article/56517   
    To resolve this issue, complete the following steps:   

  1.         Connect to the management switch via SSH or using a console connection.     
  3.         Edit the following file using a text editor: /etc/cumulus/switchd.conf     
  5.         Remove the hash sign (i.e., the '#' character) from the beginning of the line that starts with resv_vlan_range. The line will be similar to the following:       
             #resv_vlan_range = 3000-3999       
  7.         Adjust the range to exclude the VLANs that are configured in the environment. The IDs can be anywhere between 2 and 4094 and must contain a minimum of 300 VLANs. The following would be an example of a line adjusted to exclude anything below 3700:       
             resv_vlan_range = 3700-3999       
  9.         Restart the switchd.service on the switch with the following command:       
             sudo systemctl restart switchd.service     






The changes to the switchd.conf can also be completed using the following command:   
    sed -i "s/#resv_vlan_range = 3000-3999/resv_vlan_range = 3700-3999/g" /etc/cumulus/switchd.conf;reboot