Merge pull request #153 from yelghali/patch-7

 reduce-network-traversal-between-VMs.md

Author: russelltrow

docs/catalog/cloud/reduce-network-traversal-between-VMs.md

@@ -0,0 +1,40 @@
+---
+version: 1.0
+submitted_by: yelghali
+published_date: tbd
+category: cloud
+tags: 
+- cloud
+- network
+- compute
+- kubernetes
+- role:cloud-engineer
+- size:medium
+---
+
+# Reduce network traversal between VMs
+
+## Description
+Placing VMs in a single region or a single availability zone reduces the physical distance between the instances. 
+
+## Solution
+Choose the VM placement that is best for your workload. 
+
+Most cloud providers provide various options, like
+- https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/placement-groups.html
+- https://cloud.google.com/compute/docs/instances/define-instance-placement
+- https://learn.microsoft.com/en-us/azure-stack/hci/manage/vm-affinity
+
+## SCI Impact
+`SCI = (E * I) + M per R`
+[Software Carbon Intensity Spec](https://grnsft.org/sci)
+
+Regarding the SCI equation, reducing network traversal between VMs will impact:
+
+- `E`: By reducing network travel distance, we reduce the amount of energy consumed.
+
+## Assumptions
+- VM placement options provided by cloud providers are adequate for this workload,
+
+## Considerations
+- For business critical workloads, you need to ensure your workload is spread across multiple availability-zones, which may result in more network traversal and increase in your carbon footprint.