#!/bin/bash

# 获取 k8s 集群中所有节点的资源使用情况
# 使用方法：./k8s-resource-usage.sh
# 还可以使用 kubectl top node 命令获取资源使用情况

function kusage() {
    local node_count=0
    local total_percent_cpu=0
    local total_percent_mem=0

    if ! command -v kubectl &> /dev/null; then
        echo "kubectl could not be found"
        exit 1
    fi

    # 表头
    printf "%-20s %-18s %-22s %-15s %-18s %-15s %-15s\n" \
        "NODE" "CPU_allocatable" "Memory_allocatable" "CPU_requests" "Memory_requests" "CPU_limits" "Memory_limits"

    for n in $(kubectl get nodes --no-headers -o custom-columns=NAME:.metadata.name); do
        local requests abs_cpu percent_cpu node_cpu allocatable_cpu percent_cpu_lim
        local abs_mem percent_mem node_mem allocatable_mem allocatable_mem_mib percent_mem_lim

        requests=$(kubectl describe node "$n" | grep -A2 -E "Resource" | tail -n1 | tr -d '(%)')
        abs_cpu=$(echo "$requests" | awk '{print $2}')
        percent_cpu=$(echo "$requests" | awk '{print $3}')
        node_cpu=$(echo "$abs_cpu $percent_cpu" | tr -d 'mKi' | awk '{print int($1/$2*100)}')
        allocatable_cpu=$(echo "$node_cpu $abs_cpu" | tr -d 'mKi' | awk '{print int($1 - $2)}')
        percent_cpu_lim=$(echo "$requests" | awk '{print $5}')

        requests=$(kubectl describe node "$n" | grep -A3 -E "Resource" | tail -n1 | tr -d '(%)')
        abs_mem=$(echo "$requests" | awk '{print $2}')
        percent_mem=$(echo "$requests" | awk '{print $3}')
        node_mem=$(echo "$abs_mem $percent_mem" | tr -d 'mKi' | awk '{print int($1/$2*100)}')
        allocatable_mem=$(echo "$node_mem $abs_mem" | tr -d 'mKi' | awk '{print int($1 - $2)}')
        allocatable_mem_mib=$((allocatable_mem / 1024 / 1024))
        percent_mem_lim=$(echo "$requests" | awk '{print $5}')

        printf "%-20s %-18s %-22s %-15s %-18s %-15s %-15s\n" \
            "$n" "${allocatable_cpu}m" "${allocatable_mem_mib}MiB" "${percent_cpu}%" "${percent_mem}%" "${percent_cpu_lim}%" "${percent_mem_lim}%"

        node_count=$((node_count + 1))
        total_percent_cpu=$((total_percent_cpu + percent_cpu))
        total_percent_mem=$((total_percent_mem + percent_mem))
    done

    avg_percent_cpu=$((total_percent_cpu / node_count))
    avg_percent_mem=$((total_percent_mem / node_count))

    echo ""
    echo "Average usage (requests) : ${avg_percent_cpu}% CPU, ${avg_percent_mem}% memory."
}
kusage "$@"