Move control-loop note from principle to glossary for now (#31)

* Add control-loop principle for consideration.

Signed-off-by: Dan Garfield <[email protected]>

* Add link

Signed-off-by: Dan Garfield <[email protected]>

* Remove extra dash

Signed-off-by: Dan Garfield <[email protected]>

* Improve inclusivity of language

Co-authored-by: Scott Rigby <[email protected]>
Signed-off-by: Dan Garfield <[email protected]>

* Add feedback reference to reconcilliation

Signed-off-by: Dan Garfield <[email protected]>

* Move closed-loop to glossary to avoid confusion in the principles.

Signed-off-by: Dan Garfield <[email protected]>

Co-authored-by: Scott Rigby <[email protected]>

* Remove closed loop from the principles and focus in the glossary

Signed-off-by: Dan Garfield <[email protected]>

* Update GLOSSARY.md

Signed-off-by: Dan Garfield <[email protected]>

Co-authored-by: Scott Rigby <[email protected]>

* Update GLOSSARY.md

Signed-off-by: Dan Garfield <[email protected]>

Co-authored-by: Jesse Butler <[email protected]>
Co-authored-by: Moshe Immerman <[email protected]>
Co-authored-by: Lloyd Chang <[email protected]>
Co-authored-by: Christian Hernandez <[email protected]>
Co-authored-by: Michael Bridgen <[email protected]>

Co-authored-by: Scott Rigby <[email protected]>

Author: todaywasawesome

GLOSSARY.md

@@ -22,7 +22,8 @@ This glossary accompanies the [GitOps Principles](./PRINCIPLES.md), and other su
 - ## Reconciliation
 
     The process of ensuring the actual state of a system matches its [desired state](#desired-state).
-    Contrary to traditional CI/CD where automation is generally driven by pre-set triggers, in GitOps reconciliation is triggered whenever there is a divergence. Divergence could be due to the actual state unintentionally [drifting](#drift) from the desired state declarations, or a new desired state declaration version having been changed intentionally.
+    Contrary to traditional CI/CD where automation is generally driven by pre-set triggers, in GitOps reconciliation is triggered whenever there is a divergence with [feedback](#feedback) from previous attempts. Divergence could be due to the actual state unintentionally [drifting](#drift) from the desired state declarations, or a new desired state declaration version having been changed intentionally.
+    Actions are taken based on policies around [feedback](./GLOSSARY.md#feedback) from the system and previous reconciliation attempts, in order to reduce deviation over time.
 
 - ## Software System
 
@@ -38,3 +39,8 @@ This glossary accompanies the [GitOps Principles](./PRINCIPLES.md), and other su
     This state store should provide access control and auditing on the changes to the Desired State.
     Git, from which GitOps derives its name, is the canonical example used as this state store but any other system that meets these criteria may be used.
     In all cases, these state stores must be properly configured and precautions must be taken to comply with requirements set out in the GitOps Principles.
+
+- ## Feedback
+
+    Open GitOps follows [control-theory](https://en.wikipedia.org/wiki/Control_theory) and operates in a closed-loop. In control theory, feedback represents how previous attempts to apply a desired state have affected the actual state. For example if the desired state requires more resources than exist in a system, the software agent may make attempts to add resources, to automatically rollback to a previous version, or to send alerts to human operators.
+

PRINCIPLES.md

@@ -19,4 +19,4 @@ The [desired state](./GLOSSARY.md#desired-state) of a GitOps managed system must
 
 4. **Continuously Reconciled**
 
-    Software agents [continuously](./GLOSSARY.md#continuous) observe actual system state and [attempt to apply](./GLOSSARY.md#reconciliation) the desired state.
+    Software agents [continuously](./GLOSSARY.md#continuous) observe actual system state and [attempt to apply](./GLOSSARY.md#reconciliation) the desired state.