We're going to switch off labservices1001 and labservices1002 pretty soon. This is an opportunity to create new 'cloud-' name server addresses and move all the load onto cloudservices1003 and cloudservices1004.
The actual DNS content is synced between all four servers, so we can safely switch things over as DNS updates.
before
labservices1001
208.80.155.117: labservices1001.wikimedia.org, labs-ns0.wikimedia.org
208.80.155.118: labs-recursor0.wikimedia.org
labservices1002
208.80.154.12: labservices1002.wikimedia.org, labs-ns1.wikimedia.org
208.80.154.20: labs-recursor1.wikimedia.org
cloudservices1003
208.80.154.135: cloudservices1003.wikimedia.org, labs-ns2.wikimedia.org
208.80.154.143: labs-recursor2.wikimedia.org
cloudservices1004
208.80.154.11: cloudservices1004.wikimedia.org, labs-ns3.wikimedia.org
208.80.154.24: labs-recursor3.wikimedia.org
cloud vm resolv.conf:
nameserver 208.80.155.118 nameserver 208.80.154.20
after
labservices1001
208.80.155.117: labservices1001.wikimedia.org
labservices1002
208.80.154.12: labservices1002.wikimedia.org
cloudservices1003
208.80.154.135: cloudservices1003.wikimedia.org, cloud-ns0.wikimedia.org
208.80.154.143: cloud-recursor0.wikimedia.org
cloudservices1004
208.80.154.11: cloudservices1004.wikimedia.org, cloud-ns1.wikimedia.org
208.80.154.24: cloud-recursor1.wikimedia.org
cloud vm resolv.conf:
nameserver 208.80.154.143 nameserver 208.80.154.24