kubectl get 中嵌套数组的 jsonpath

Question

我正在尝试获取 Kubernetes pod 的资源限制和请求。我试图输出到一个逗号分隔的行，其中列出了命名空间、pod 名称、容器名称，然后是每个容器的内存和 CPU 限制/请求。当每个 pod 有多个容器时会遇到问题。

我能得到的最接近的是这个，它将为每个 pod 打印一行。如果有多个容器，它们将列在同一行的单独“列”中。

kubectl get pods --all-namespaces -o jsonpath='{range .items[*]}{@.metadata.namespace}{","}{@.metadata.name}{","}{range .spec.containers[*]}{.name}{","}{@.resources.requests.cpu}{","}{@.resources.requests.memory}{","}{@.resources.limits.cpu}{","}{@.resources.limits.memory}{","}{end}{"\n"}{end}'

输出如下所示：

kube-system,metrics-server-5f8d84558d-g926z,metrics-server-vpa,5m,30Mi,100m,300Mi,metrics-server,46m,63Mi,46m,63Mi,

我想看到的是这样的：

kube-system,metrics-server-5f8d84558d-g926z,metrics-server-vpa,5m,30Mi,100m,300Mi,
kube-system,metrics-server-5f8d84558d-g926z,metrics-server,46m,63Mi,46m,63Mi,

感谢任何帮助。谢谢。

Answer 1

我认为您不能仅使用 kubectl 的（有限的）JSONPath。

有一个 UNIX 原则，即每个工具都应该做好一件事：

• kubectl 做 Kubernetes 的东西很好，可以输出 JSON
• jq JSON 处理得很好。

如果您愿意使用其他工具：

FILTER='
  .items[]
  |.metadata as $meta
  |.spec.containers[]
  |.name as $name
  |.resources.requests as $requests
  |.resources.limits as $limits
  |[ 
     $meta.namespace,
     $meta.name,$name,
     $requests.cpu,
     $requests.memory,
     $limits.cpu,
     $limits.memory
   ]
  |@csv
'

kubectl get pods 
--all-namespaces 
--output=json 
| jq -r "${FILTER}"

解释：

1. 对于每个items（即每个 Pod）
2. 将变量meta设置为（Pod的）metadata内容
3. 对于每个containers（即每个容器）
4. 将变量name设置为（容器的）name
5. 将变量requests设置为（容器的资源）requests
6. 将变量limits设置为（容器的资源）limits
7. 通过重新组装相关部分创建一个数组（[...]）
8. 以逗号分隔的形式输出数组

   在集群上：

   "monitoring","prometheus-adapter-59df95d9f5-kg4hc","prometheus-adapter",,,,
   "monitoring","prometheus-adapter-59df95d9f5-j6rbx","prometheus-adapter",,,,
   "monitoring","prometheus-operator-7775c66ccf-45z2f","prometheus-operator","100m","100Mi","200m","200Mi"
   "monitoring","prometheus-operator-7775c66ccf-45z2f","kube-rbac-proxy","10m","20Mi","20m","40Mi"
   "monitoring","node-exporter-7cf4m","node-exporter","102m","180Mi","250m","180Mi"
   "monitoring","node-exporter-7cf4m","kube-rbac-proxy","10m","20Mi","20m","40Mi"
   "monitoring","kube-state-metrics-76f6cb7996-hdxcb","kube-state-metrics","10m","190Mi","100m","250Mi"
   "monitoring","kube-state-metrics-76f6cb7996-hdxcb","kube-rbac-proxy-main","20m","20Mi","40m","40Mi"
   "monitoring","kube-state-metrics-76f6cb7996-hdxcb","kube-rbac-proxy-self","10m","20Mi","20m","40Mi"
   "monitoring","blackbox-exporter-55c457d5fb-x6hwj","blackbox-exporter","10m","20Mi","20m","40Mi"
   "monitoring","blackbox-exporter-55c457d5fb-x6hwj","module-configmap-reloader","10m","20Mi","20m","40Mi"
   "monitoring","blackbox-exporter-55c457d5fb-x6hwj","kube-rbac-proxy","10m","20Mi","20m","40Mi"
   "monitoring","grafana-6dd5b5f65-6jwq8","grafana","100m","100Mi","200m","200Mi"
   "monitoring","alertmanager-main-0","alertmanager","4m","100Mi","100m","100Mi"
   "monitoring","alertmanager-main-0","config-reloader","100m","50Mi","100m","50Mi"
   "kube-system","coredns-7f9c69c78c-2zx4h","coredns","100m","70Mi",,"170Mi"
   "monitoring","prometheus-k8s-0","prometheus",,"400Mi",,
   "monitoring","prometheus-k8s-0","config-reloader","100m","50Mi","100m","50Mi"
   "kube-system","calico-kube-controllers-5f7575cc96-6tf8x","calico-kube-controllers",,,,
   "kube-system","calico-node-m78xm","calico-node","250m",,,