A script to count pod zone distribution on GCP. Use to find out how many pods are in which zones. Works with Ruby 3.0+

finding-service-zone-distribution-gcp-gke.rb

require 'csv'
running_instances = `gcloud compute instances list | ack <node-name> | ack RUNNING`
parsed_instance_list = CSV.parse(running_instances.squeeze(' ').gsub(' ', ','))

# instance name as key, region as value
instance_name_with_region = parsed_instance_list
  .group_by do |a|
    a[0]
  end
  .map do |k, v|
    [k, v[0][1]]
  end.to_h

pods_list_raw = `kubectl get pod -nads -o wide | ack <service-pod-name> | ack Running`
pods_list = CSV.parse(adrequest_pods_list_raw.squeeze(' ').gsub(' ', ','))

zone_bucket = { a: 0, b: 0, c: 0 }
pods_list.each do |pod|
  # get zone by pod node instance name
  case instance_name_with_region[pod[6]]
  in "us-central1-a"
    zone_bucket[:a] += 1
  in "us-central1-b"
    zone_bucket[:b] += 1
  in "us-central1-c"
    zone_bucket[:c] += 1
  else
    puts "No zone: #{pod}"
  end
end

puts zone_bucket