Class: Kube::Cluster::Middleware::ResourcePreset

Inherits:
Kube::Cluster::Middleware show all
Defined in:
lib/kube/cluster/middleware/resource_preset.rb

Overview

Reads the app.kubernetes.io/size label from pod-bearing resources and injects CPU/memory requests and limits into every container.

The label on the resource is the input:

Kube::Cluster["Deployment"].new {
  metadata.labels = { "app.kubernetes.io/size": "small" }
  ...
}

Register in the stack — no arguments needed:

stack do
  use Middleware::ResourcePreset
end

Available sizes: nano, micro, small, medium, large, xlarge, 2xlarge. Limits are ~1.5x requests (following Bitnami conventions).

Constant Summary collapse

LABEL = 
:"app.kubernetes.io/size"
PRESETS = 
{
  "nano"    => { requests: { cpu: "100m",  memory: "128Mi"  }, limits: { cpu: "150m",  memory: "192Mi"  } },
  "micro"   => { requests: { cpu: "250m",  memory: "256Mi"  }, limits: { cpu: "375m",  memory: "384Mi"  } },
  "small"   => { requests: { cpu: "500m",  memory: "512Mi"  }, limits: { cpu: "750m",  memory: "768Mi"  } },
  "medium"  => { requests: { cpu: "500m",  memory: "1024Mi" }, limits: { cpu: "750m",  memory: "1536Mi" } },
  "large"   => { requests: { cpu: "1",     memory: "2048Mi" }, limits: { cpu: "1.5",   memory: "3072Mi" } },
  "xlarge"  => { requests: { cpu: "1",     memory: "3072Mi" }, limits: { cpu: "3",     memory: "6144Mi" } },
  "2xlarge" => { requests: { cpu: "1",     memory: "3072Mi" }, limits: { cpu: "6",     memory: "12288Mi" } },
}.freeze

Instance Method Summary collapse

Methods inherited from Kube::Cluster::Middleware

#initialize

Constructor Details

This class inherits a constructor from Kube::Cluster::Middleware

Instance Method Details

#call(manifest) ⇒ Object 



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# File 'lib/kube/cluster/middleware/resource_preset.rb', line 39

def call(manifest)
  manifest.resources.map! do |resource|
    size = resource.label(LABEL)
    next resource unless size
    next resource unless resource.pod_bearing?

    preset = PRESETS.fetch(size.to_s) do
      raise ArgumentError, "Unknown size preset: #{size.inspect}. " \
        "Valid sizes: #{PRESETS.keys.join(', ')}"
    end

    h = resource.to_h
    pod_spec = resource.pod_template(h)
    next resource unless pod_spec

    resource.each_container(pod_spec) do |container|
      container[:resources] = deep_merge(preset, container[:resources] || {})
    end

    resource.rebuild(h)
  end
end