Fleet autoscaler with "List" policy throws an error if configured with a fleet with no replicas #3943
Description
What happened:
If we setup a fleet without defining "replicas" and setup an autoscaler with "List" policy, the autoscaler throws the following error.
Error calculating desired fleet size on FleetAutoscaler simple-game-server-autoscaler. Error: cannot apply ListPolicy as List key MyCustomList does not exist in the Fleet Status
What you expected to happen:
The fleet autoscaler should be able to determine the desired number of replicas even if there is no replicas present.
How to reproduce it (as minimally and precisely as possible):
Setup a fleet with no replicas defined, and a list based autoscaler for the fleet.
Ex.
---
apiVersion: agones.dev/v1
kind: Fleet
metadata:
name: simple-game-server
spec:
template:
spec:
lists:
MyCustomList:
capacity: 50
ports:
- name: default
containerPort: 7654
template:
spec:
containers:
- name: simple-game-server
image: us-docker.pkg.dev/agones-images/examples/simple-game-server:0.34
resources:
requests:
memory: 64Mi
cpu: 20m
limits:
memory: 64Mi
cpu: 20m
---
apiVersion: autoscaling.agones.dev/v1
kind: FleetAutoscaler
metadata:
name: simple-game-server-autoscaler
spec:
fleetName: simple-game-server
policy:
type: List # List based autoscaling.
list:
key: MyCustomList
bufferSize: 10%
minCapacity: 50
maxCapacity: 800
Below is the describe output of the fleet autoscaler
Name: simple-game-server-autoscaler
Namespace: default
Labels: <none>
Annotations: <none>
API Version: autoscaling.agones.dev/v1
Kind: FleetAutoscaler
Metadata:
Creation Timestamp: 2024-08-12T14:35:58Z
Generation: 1
Resource Version: 28009
UID: 91ff6589-e3c4-4456-b5b4-e31767a8ac03
Spec:
Fleet Name: simple-game-server
Policy:
List:
Buffer Size: 10%
Key: MyCustomList
Max Capacity: 800
Min Capacity: 50
Type: List
Sync:
Fixed Interval:
Seconds: 30
Type: FixedInterval
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Warning FleetAutoscaler 12s (x25 over 76s) fleetautoscaler-controller Error calculating desired fleet size on FleetAutoscaler simple-game-server-autoscaler. Error: cannot apply ListPolicy as List key MyCustomList does not exist in the Fleet Status
Anything else we need to know?:
This is crucial for agones to be used with "Flux CD" (https://fluxcd.io/) and probably other gitops based tools.
Environment:
- Agones version: 1.42
- Kubernetes version (use
kubectl version): 1.27.1 - Cloud provider or hardware configuration: Minikube
- Install method (yaml/helm): helm
- Troubleshooting guide log(s):
- Others: