Operational Excellence - The Practice of Cloud System Administration - page 408

Defined versus Managed
People often have a difficult time conceptualizing the subtle difference between
Levels 3 and 4. Consider the example of assessing the load balancer aspect of a
service. Load balancers can be used to improve capacity or resiliency, or both. Re-
siliencyrequiresthesystemtorunwithenoughsparecapacitytowithstandafailed
backend. (See Section 6.3 . )
If there is a written policy that the load balancer is used for resiliency, this is
a Level 3 behavior. If there exists monitoring that determines the current level of
redundancy ( N + 0, N + 1, and so on), this is Level 4 behavior. In this case, Level
4 is significantly more difficult to achieve because it requires a lot of effort to ac-
curatelydeterminethemaximumcapacityofabackend,whichisrequiredtoknow
how much spare capacity is available.
Somewhat surprisingly, we have found many situations where there is no clear
sense of how a load balancer is being used, or there is disagreement among team
membersaboutwhethertheroleofaloadbalanceristoimprovecapacity ortoim-
prove resiliency. This demonstrates Level 1 behavior.
20.3.3 Assessment Questions and Look-For's
To perform an assessment for an operational responsibility, describe the current practices
in that area. Based on this description, evaluate which level describes the current practices.
To help this process, we have developed a standard set of questions to ask to help form
your description.
We've also developed a set of look-for's for each level. A look-for is a behavior, indic-
ator, or outcome common to a service or organization at a particular level. In other words,
it is “what a level looks like.” If you read a description and it “sounds like you're talking
about where I work,” then that's a good indication that your organization is at that level for
that service.
For example, in Regular Tasks, at Level 1 there is no playbook of common operational
duties,noristherealistofwhatthosedutiesare.AtLevel3thosedutieshavebeendefined
and documented.
Look-for'sarenotchecklists.Onedoesnothavetodemonstrateeverylook-fortobeas-
sessed at that level. Some look-for's are appropriate only for certain situations or services.
Look-for's are simply signals and indicators, not steps to follow or achievements to seek
out.