kubectl top nodes
NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
gsdjsgfhdsgfz-12345665-jisj000000 934m 24% 10439Mi 82%
gsdjsgfhdsgfz-12345665-jisj000001 717m 18% 9132Mi 72%
gsdjsgfhdsgfz-12345665-jisj000002 1099m 28% 7614Mi 60%
how to get the CPU% and MEMORY% value using java io.fabric8 kubernetes-client library.
try (KubernetesClient k8s = new DefaultKubernetesClient()) { NodeMetricsList nodeMetricsList = k8s.top().nodes().metrics(); for (NodeMetrics nodeMetrics : nodeMetricsList.getItems()) { logger.info("{} {} {}", nodeMetrics.getMetadata().getName(), nodeMetrics.getUsage().get("cpu"), nodeMetrics.getUsage().get("memory")); }
}
getting output is:-
node name
cpu:-1094942089n
memory:-7830672Ki
how will take the percentage values?
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Answer
I had to implement this same feature recently, unfortunately I didn’t find a way to get the percentages just by using the top()
API alone, I had to perform two calls, one to nodes()
in order to retrieve total capacity and another one to top()
to retrieve used capacity. Then it was just a matter of calculating percentage.
A snippet of the working code:
public static void main(String[] args) { KubernetesClient kubernetesClient = new DefaultKubernetesClient(); Map<String, Node> nodeMap = kubernetesClient.nodes().list().getItems() .stream() .collect(Collectors.toMap(node -> node.getMetadata().getName(), Function.identity())); List<NodeUsage> usageList = kubernetesClient.top().nodes().metrics().getItems() .stream() .map(metric -> new NodeUsage(nodeMap.get(metric.getMetadata().getName()), metric.getUsage())) .collect(Collectors.toList()); System.out.println(usageList); } private static class NodeUsage { private final Node node; private final BigDecimal cpuPercentage; private final BigDecimal memoryPercentage; private NodeUsage(Node node, Map<String, Quantity> used) { this.node = node; cpuPercentage = calculateUsage(used.get("cpu"), node.getStatus().getAllocatable().get("cpu")); memoryPercentage = calculateUsage(used.get("memory"), node.getStatus().getAllocatable().get("memory")); } private static BigDecimal calculateUsage(Quantity used, Quantity total) { return Quantity.getAmountInBytes(used) .divide(Quantity.getAmountInBytes(total), 2, RoundingMode.FLOOR) .multiply(BigDecimal.valueOf(100)); } public Node getNode() { return node; } public BigDecimal getCpuPercentage() { return cpuPercentage; } public BigDecimal getMemoryPercentage() { return memoryPercentage; } }