For zero-downtime rolling-updates, services need to maintain a quorum while nodes are being added and removed. When a node is added, the total member count and quorum size must be increased to avoid a potential split brain upon a network partitioning scenario if a failure or extended delay were to occur during a rolling upgrade. A complex service with many nodes may be continuously in a state of rolling-updates to upgraded OS or foundation software, add security patches, or deploy application bug fixes or new features. Assume we want a service to always be able to tolerate two node failures before halting for reliability/availability. From the table below, the minimum is 5 initial member nodes. With less than 5 nodes two node failures cause service updates to halt in order to guarantee consistency. When performing a rolling update a new node is added. When the new node is synchronized and brought into the quorum, the total member node count increases by one. This i...