The maximum number (or percentage) of VMs per zone to
disrupt at any given moment. The number of VMs calculated
from multiplying the percentage by the total number of VMs
in a zone is rounded up.
During patching, a VM is considered disrupted from the time
the agent is notified to begin until patching has completed.
This disruption time includes the time to complete reboot
and any post-patch steps.
A VM contributes to the disruption budget if its patching
operation fails either when applying the patches, running
pre or post patch steps, or if it fails to respond with a
success notification before timing out. VMs that are not
running or do not have an active agent do not count toward
this disruption budget.
For zone-by-zone rollouts, if the disruption budget in a
zone is exceeded, the patch job stops, because continuing to
the next zone requires completion of the patch process in
the previous zone.
For example, if the disruption budget has a fixed value of
10, and 8 VMs fail to patch in the current zone, the
patch job continues to patch 2 VMs at a time until the zone
is completed. When that zone is completed successfully,
patching begins with 10 VMs at a time in the next zone. If
10 VMs in the next zone fail to patch, the patch job stops.