{"type":"doc","content":[{"type":"paragraph","content":[{"text":"To scale components based on custom metrics we need to have two components:","type":"text"}]},{"type":"bulletList","content":[{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"One that collects metrics from our applications and stores them to Kloudfuse database.","type":"text"}]}]},{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"The second one that extends the Kubernetes Custom Metrics API with the metrics supplied by a collector, the ","type":"text"},{"text":"k8s-prometheus-adapter","type":"text","marks":[{"type":"underline"},{"type":"link","attrs":{"href":"https://github.com/prometheus-community/helm-charts/tree/main/charts/prometheus-adapter"}}]},{"text":". This is an implementation of the custom metrics API that attempts to support arbitrary metrics.","type":"text"}]}]}]},{"type":"paragraph"},{"type":"paragraph","content":[{"text":"Consider we have an application specific metric named ","type":"text"},{"text":"some_metric","type":"text","marks":[{"type":"code"}]},{"text":" ingested into Kfuse which we want to modify and Autoscale our pods on.","type":"text"}]},{"type":"orderedList","attrs":{"order":1},"content":[{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"First we would need to install Prometheus adapter with proper configuration to emit a custom metric ","type":"text"},{"text":"some_custom_metric","type":"text","marks":[{"type":"code"}]},{"text":" based on a query for ","type":"text"},{"text":"some_metric","type":"text","marks":[{"type":"code"}]}]}]}]},{"type":"paragraph","content":[{"text":"Create ","type":"text"},{"text":"prometheus-values.yaml","type":"text","marks":[{"type":"code"}]},{"text":" file for Prometheus Adapter configuring the proper endpoint, authentication and custom metric rules :-","type":"text"}]},{"type":"codeBlock","content":[{"text":"metricsRelistInterval: 5m\n\nprometheus:\n # Replace with your endpoint for Kloudfuse\n url: <>\n port: 443\n path: \"\"\n \n# Rules to generate `some_custom_metric` as an external metric\nrules:\n default: false\n external:\n - seriesQuery: '{__name__=~\"some_metric\"}'\n resources:\n template: <<.Resource>>\n name:\n as: \"some_custom_metric\"\n metricsQuery: avg (some_metric)\n \n# Base64 Encoded Auth string in the format <>\nextraArguments:\n - --prometheus-header=Authorization=Basic YWRtaW46cGFzc3dvcmQ=","type":"text"}]},{"type":"orderedList","attrs":{"order":2},"content":[{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"Deploy Prometheus adapter on your cluster","type":"text"}]}]}]},{"type":"codeBlock","content":[{"text":"helm install --name RELEASE_NAME prometheus-community/prometheus-adapter -f prometheus-values.yaml","type":"text"}]},{"type":"orderedList","attrs":{"order":3},"content":[{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"Verify the adapter properly emits your custom metric within the K8s external metrics api","type":"text"}]}]}]},{"type":"codeBlock","content":[{"text":"kubectl get --raw /apis/external.metrics.k8s.io/v1beta1 | jq .\n\n#Should show some output like this \n{\n \"kind\": \"APIResourceList\",\n \"apiVersion\": \"v1\",\n \"groupVersion\": \"external.metrics.k8s.io/v1beta1\",\n \"resources\": [\n {\n \"name\": \"some_custom_metric\",\n \"singularName\": \"\",\n \"namespaced\": true,\n \"kind\": \"ExternalMetricValueList\",\n \"verbs\": [\n \"get\"\n ]\n }\n ]\n}","type":"text"}]},{"type":"paragraph","content":[{"text":"For additional Prometheus-adapter configurations please refer to their Helm documentation ","type":"text"},{"text":"here","type":"text","marks":[{"type":"link","attrs":{"href":"https://github.com/prometheus-community/helm-charts/tree/main/charts/prometheus-adapter"}}]}]},{"type":"paragraph"},{"type":"paragraph","content":[{"text":"Once the custom metric is available to use within k8s metrics api, you can configure HPA to use the metric like this: ","type":"text"}]},{"type":"codeBlock","content":[{"text":"apiVersion: autoscaling/v2\nkind: HorizontalPodAutoscaler\nmetadata:\n name: <>\nspec:\n scaleTargetRef:\n apiVersion: apps/v1\n kind: Deployment\n name: <>\n minReplicas: 1\n maxReplicas: 10\n metrics:\n - type: External\n external:\n metric:\n name: some_custom_metric\n target:\n type: AverageValue\n averageValue: 100","type":"text"}]},{"type":"paragraph","content":[{"text":"For additional information on configuring HPA with Custom metrics refer to k8s documentation ","type":"text"},{"text":"here","type":"text","marks":[{"type":"link","attrs":{"href":"https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale-walkthrough/#autoscaling-on-multiple-metrics-and-custom-metrics"}}]}]}],"version":1}

Browser not supported