はじめに¶

ステータスコード413エラーって見たことがありますか？

Nginxでは1MBを超えるクライアントからのリクエストはデフォルトで413エラーを出します．今日はそれを人為的に起こしてみます．

やりかた¶

ConfigMapとDeployment，Serviceを起動する．

nginx-configmap.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: nginx-config
data:
  default.conf: |
    server {
        listen 80;
        server_name localhost;

        location /test {
            limit_except POST {
                deny all;
            }

            return 200 '{"status":"success", "message":"POST request received"}';
            add_header Content-Type application/json;
        }
    }

nginx-deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: web-container
        image: nginx
        ports:
        - containerPort: 80
        volumeMounts:
        - name: config-volume
          mountPath: /etc/nginx/conf.d
      volumes:
      - name: config-volume
        configMap:
          name: nginx-config
          items:
          - key: default.conf
            path: default.conf
---
apiVersion: v1
kind: Service
metadata:
  name: myapp
  labels:
    app: myapp
spec:
  ports:
  - name: http
    port: 80
  selector:
    app: myapp
  type: NodePort

実行する

$ kubectl apply -f nginx-configmap.yaml
$ kubectl apply -f nginx-deployment.yaml

monitoring_prometheus-operatorのログ(正常)をPOST用にダウンロードします． 0.log (1.1 MB)

Kubernetes control planeのアドレスを取得します．

$ kubectl cluster-info
Kubernetes control plane is running at https://192.168.100.203:6443
CoreDNS is running at https://192.168.100.203:6443/api/v1/namespaces/kube-system/services/rke2-coredns-rke2-coredns:udp-53/proxy

To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.

Serviceで用いているPortを取得します．

$ kubectl get svc
NAME    TYPE       CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
myapp   NodePort   10.43.85.188   <none>        80:30042/TCP   66m

POSTする場所は/testです．よってURLはhttps://192.168.100.203:30042/testとなります．

postcurl.sh

#bin/bash
URL=http://192.168.100.203:30042/test
FILE=0.log
INPUTNAME=upfile


echo "413"
curl -X POST $URL -F $INPUTNAME=@$FILE

echo ""

echo "status:successと出たら成功！！"
curl -X POST $URL -d 'data=example'

echo ""

$ chmod +x postcurl.sh
$ ./postcurl.sh

実行結果として，1.1MBの0.logは413エラーで失敗し，data=exampleを送信した場合は成功しています．

413
<html>
<head><title>413 Request Entity Too Large</title></head>
<body>
<center><h1>413 Request Entity Too Large</h1></center>
<hr><center>nginx/1.25.3</center>
</body>
</html>

status:successと出たら成功！！
{"status":"success", "message":"POST request received"}