Section 3.3.3 Bureaucrats
Parliament could no longer handle all details of government, so a bureaucracy was established. Instead of passing a decree to declare whether each lot of cheese was fit for sale, Parliament passed a decree appointing a cheese inspector to make those decisions.LAMPORT, P. 18 — §3.3.3
A bureaucrat in a Paxos-based system is a program that has been delegated authority to act on behalf of the system. Rather than participating in consensus or voting, it applies decisions once they have been agreed upon. Examples include components that manage leases or apply agreed-upon operations; state machine replication (SMR) is a common use case. Many such bureaucrats can be built on top of Paxos, but they are not the primary focus of the paper.
The paper instead focuses on how safety can be maintained when authority is transferred from one bureaucrat to another.
It soon became evident that selecting bureaucrats was not as simple as it first seemed. Parliament passed a decree making ∆˘ικστρα the first cheese inspector. After some months, merchants complained that ∆˘ικστρα was too strict and was rejecting perfectly good cheese. Parliament then replaced him by passing the decree 1375: Γωυδα is the new cheese inspector But ∆˘ικστρα did not pay close attention to what Parliament did, so he did not learn of this decree right away. There was a period of confusion in the cheese market when both ∆˘ικστρα and Γωυδα were inspecting cheese and making conflicting decisions. To prevent such confusion, the Paxons had to guarantee that a position could be held by at most one bureaucrat at any time. To do this, a president included as part of each decree the time and date when it was proposed.LAMPORT, P. 18 — §3.3.3
His solution is to appoint bureaucrats for fixed terms, with explicit start and end times.
A bureaucrat was appointed for a short term, so he could be replaced quickly— for example, if he left the island. Parliament would pass a decree to extend the bureaucrat’s term if he was doing a satisfactory job. A bureaucrat needed to tell time to determine if he currently held a post. Mechanical clocks were unknown on Paxos, but Paxons could tell time accurately to within 15 minutes by the position of the sun or the stars.13 If ∆˘ικστρα’s term began at 8:30, he would not start inspecting cheese until his celestial observations indicated that it was 8:45.LAMPORT, P. 18 — §3.3.3
Terms begin after a delay to ensure that the decree has propagated to all relevant nodes, preventing conflicting bureaucrats from acting simultaneously due to stale information.
This is more a thought experiment than a recipe. He's laying out ground work about how this is safe but this isn't a full working spec.