Changing a network subnet range in existing Overcloud

Issue

• We have been allocated a new subnet to be used for InternalApiAllocationPools from our network department because the current subnet is full and we would like to update our current overcloud templates as well as the current infrastructure to use the new subnet in order to be able to scale out our current deployment.

• In network-environment.yaml we have the following configured:

  InternalApiNetCidr: 172.17.0.0/24                 
  StorageNetCidr: 172.18.0.0/24                     
  StorageMgmtNetCidr: 172.19.0.0/24                 
  TenantNetCidr: 172.16.0.0/24                      
  ExternalNetCidr: 192.168.122.0/24                 
  InternalApiAllocationPools: [{'start': '172.17.0.10', 'end': '172.17.0.200'}]                          
  StorageAllocationPools: [{'start': '172.18.0.10', 'end': '172.18.0.200'}]                              
  StorageMgmtAllocationPools: [{'start': '172.19.0.10', 'end': '172.19.0.200'}]                          
  TenantAllocationPools: [{'start': '172.16.0.10', 'end': '172.16.0.200'}]                               
  # Use an External allocation pool which will leave room for floating IPs                               
  ExternalAllocationPools: [{'start': '192.168.122.130', 'end': '192.168.122.150'}]