SLA
Service Level Agreement. An external promise about service levels, often with penalties or consequences if it is missed.
Definition
An SLA (Service Level Agreement) is an external promise about service level.
If you miss it, there are consequences.
Most internal systems do not need an SLA.
They still benefit from SLIs and SLOs.
Example
“If monthly availability is below 99.9%, customers receive service credits.”
That is an SLA because it is an external promise with consequences.
Common mistake
Using “SLA” as a synonym for “SLO.”
SLA implies an external commitment and consequences.