Automation - The Practice of Cloud System Administration - page 241

Terms to Know
Domain-Specific Language (DSL): A language that was purpose-built for a par-
ticular use, such as system administration, mathematics, or text manipulation.
Toil: Exhausting physical labor.
12.1 Approaches to Automation
There are three primary approaches to automation design. The first, and most common,
approach is to automate using the “left-over” principle, where the automation handles as
much as possible, with people being expected to handle whatever is left over. The second
approach is the “compensatory” principle, where the work is divided between people and
the automation based on which one is better at which task. The third approach is based
on the complementarity principle, which aims to improve the long-term health of the com-
bined system of people and computers.
Automation impacts things beyond the immediate intended goal. Understanding what
the unintended consequences of automation are likely to be should aid you in building a
healthier overall system. For example, antilock brakes (ABS) make it easier for a driver to
stop a car more quickly in an emergency. In isolation, this automation should reduce acci-
dents.However,thepresenceofthisautomationaffectshowpeopledrive.Theydrivemore
quicklyinslipperyconditionsthantheywouldwithoutABS,andtheyleaveshortergapsto
the car in front because of their confidence in the ABS automation. These are unintended
consequences of the automation. When human factors are not taken into account, automa-
tion can have unexpected, and perhaps negative, consequences.
Bear in mind that not all tasks should be automated. Some difficult tasks are so rare
that they happen exactly once and cannot happen again—for example, installing a large,
complex, software system. This is where you outsource. Hire a consultant who has done it
before, since the situation is so rare that the learning curve has no payoff. The result of the
consultant'sworkshouldincludeasetofcommontasksthatareperformedmorefrequently
and are handed off to the regular operations staff or to the automation.
Alsobearinmindthateliminatingatask,whetheritiseasy,difficult,frequent,orrare,is
beneficial because it becomes one less thing to know, do, or maintain. If you can eliminate
the task, rather than automating it, that will be the most efficient approach. The co-creator
of UNIX and the C programming language, Ken Thompson, famously wrote, “One of my
most productive days was throwing away 1,000 lines of code.”