feat(isg): started concepts

Author: RoRoJ

compute/instance-scaling-groups/concepts.mdx

@@ -11,4 +11,60 @@ dates:
   validation: 2024-11-25
 categories:
   - compute
----
+---
+
+## Aggregation method
+
+The method used by a [scaling policy](#scaling-policy) to aggregate all the metric data collected during the specified sampling time range. Based on the data collected and aggregated, the defined threshold for a scaling action will be considered to be met or not. Aggregation methods are: **average**, **minimum**, **maximum**, and **sum**. The default method is **average**.
+
+## Group cooldown period
+
+After a scaling action is carried out on an Instance Scaling Group, no further scaling actions will be taken until the user-defined **cooldown period** has elapsed. This is designed to prevent over-scaling, giving the group time to stabilize before determining whether another scaling action is appropriate.
+
+## Group capacity limits
+
+Group capacity limits define the minimum and maximum number of Instances for an Instance Scaling Group. The group will always contain no fewer than the minimum number of Instances defined, and never exceed the maximum. 
+
+## Image
+
+The image that runs on the Instances that make up the Instance Scaling Group. The same image must necessarily be used by all the Instances of the group, and it must be one of your own [images](/compute/instances/concepts/#image) or [snapshots](/compute/instances/concepts/#snapshot), already created in your Scaleway Project. 
+
+## Instance Scaling Group
+
+Instance Scaling Groups are groups of Instances all based on the same defined template, and having an attached scaling policy. Metrics for the group are regularly checked (e.g. total CPU usage or network traffic) and if scaling policy conditions are met, the group is scaled up or down accordingly. The group has a Load Balancer attached, which provides a single entry point to the Instances and distributes traffic between them. Instance Scaling Groups help you to ensure optimal performance and efficient cost management. 
+
+## Instance template
+
+Instance templates define the model for Instances in a given group. When scaling up, the Instance group will create Instances based on this template. 
+
+When creating an Instance template, you define an Availability Zone, [Instance type](/compute/instances/reference-content/choosing-instance-type/), [image](##image), [volumes](/compute/instances/concepts/#volumes), network connectivity (public IP address and/or Private Network connections), [security group](#security-group) and [placement group](#placement-group) for the templated Instance. 
+
+## Load Balancer
+
+Every Instance Scaling Group must have a Scaleway [Load Balancer](/network/load-balancer/concepts/#load-balancers) attached to it. The Load Balancer distributes traffic to the Instances in the group according to its defined [balancing method](/network/load-balancer/concepts/#balancing-methods), and carries out [health checks](/network/load-balancer/concepts/#health-checks) to ensure it only forwards traffic to healthy Instances.
+
+## Placement group
+
+## Private Network
+
+## Resource deletion error
+
+## Sampling range
+
+## Scaling action
+
+## Scaling policy
+
+Scaling policies define how the number of Instances in the group is adjusted in response to changes in demand. Whether based on real-time resource metrics or scheduled actions, these policies ensure your infrastructure scales efficiently to maintain performance while optimizing costs.
+
+## Scaling type
+
+## Scaling value
+
+## Security group
+
+## Trigger
+
+## Volume
+
+