lesson 6

Author: nrk-simple

Readme.md

@@ -11,3 +11,4 @@
 - [урок про volumes](lesson-3/)
 - [урок про StatefullSet и CertManager](lesson-4/)
 - [урок про Advanced Scheduling](lesson-5/)
+- [урок про Advanced Scheduling Part 2](lesson-6/)

lesson-5/3/3-deploy-v2.yaml

@@ -17,3 +17,8 @@ spec:
       containers:
       - image: luksa/kubia:v2
         name: nodejs
+  strategy:
+    type: RollingUpdate
+    rollingUpdate:
+      maxSurge: 1
+      maxUnavailable: 0

lesson-6/1/01-dep.yaml

@@ -0,0 +1,46 @@
+---
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: demo-ns
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: probe
+  namespace: demo-ns
+  labels:
+    app: probe
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: probe
+  template:
+    metadata:
+      name: probe
+      labels:
+        app: probe
+    spec:
+      containers:
+      - name: probe
+        image: nar3k/probe
+        readinessProbe:
+          httpGet:
+            path: /healthz
+            port: 8080
+          periodSeconds: 10
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: probe
+  namespace: demo-ns
+spec:
+  selector:
+    app: probe
+  ports:
+    - protocol: TCP
+      port: 80
+      targetPort: 8080
+  type: LoadBalancer

lesson-6/1/readme.md

@@ -0,0 +1,43 @@
+#  Probes
+
+```
+cd lesson-6/1
+```
+
+Создадим deployment с пробами:
+
+```sh
+kubectl apply -f 01-dep.yaml
+```
+
+Запустим в фоне поиск по приложению
+```
+watch kubectl describe svc -n demo-ns
+```
+
+Посылаем curl по IP адресу балансера
+
+```
+URL=$(kubectl get svc probe -n demo-ns -o json | jq -r .status.loadBalancer.ingress[0].ip)
+curl $URL/healthz
+```
+
+
+1) сначала он не будет приходить ( потому что нода не стала еще ready )
+2) через 30 секунд в Endpoints появятся узлы и запросы начнут приходить
+3) через минуту запросы перестанут приходить совсем и ноды продадут из endpoint
+
+4) заглянем в логи что случилось
+
+```
+kubectl describe po -n demo-ns
+```
+
+Увидим сообщения о проблемах со readyness probe
+
+
+Удалим лабу
+
+```
+kubectl delete -f 01-dep.yaml
+```

lesson-6/1/service/Dockerfile

@@ -0,0 +1,6 @@
+FROM golang:latest
+RUN mkdir /app
+ADD . /app/
+WORKDIR /app
+RUN go build -o main .
+CMD ["/app/main"]

lesson-6/1/service/main.go

@@ -0,0 +1,53 @@
+package main
+
+/*
+Copyright 2014 The Kubernetes Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// A simple server that is alive for 10 seconds, then reports unhealthy for
+// the rest of its (hopefully) short existence.
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"net/url"
+	"time"
+)
+
+func main() {
+	started := time.Now()
+	http.HandleFunc("/started", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		data := (time.Since(started)).String()
+		w.Write([]byte(data))
+	})
+	http.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
+		duration := time.Since(started)
+		if duration.Seconds() < 30 || duration.Seconds() > 60 {
+			w.WriteHeader(500)
+			w.Write([]byte(fmt.Sprintf("error: %v", duration.Seconds())))
+		} else {
+			w.WriteHeader(200)
+			w.Write([]byte(fmt.Sprintf("ok: %v", duration.Seconds())))
+		}
+	})
+	http.HandleFunc("/redirect", func(w http.ResponseWriter, r *http.Request) {
+		loc, err := url.QueryUnescape(r.URL.Query().Get("loc"))
+		if err != nil {
+			http.Error(w, fmt.Sprintf("invalid redirect: %q", r.URL.Query().Get("loc")), http.StatusBadRequest)
+			return
+		}
+		http.Redirect(w, r, loc, http.StatusFound)
+	})
+	log.Fatal(http.ListenAndServe(":8080", nil))
+}

lesson-6/2/02-dep.yaml

@@ -0,0 +1,34 @@
+---
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: demo-ns
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: nginx
+  namespace: demo-ns
+  labels:
+    app: nginx
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: nginx
+  template:
+    metadata:
+      name: nginx
+      labels:
+        app: nginx
+    spec:
+      containers:
+      - name: nginx
+        image: nginx
+        resources:
+          requests:
+            memory: "64Mi"
+            cpu: "250m"
+          limits:
+            memory: "100Gi"
+            cpu: "50000m"

lesson-6/2/Readme.md

@@ -0,0 +1,58 @@
+
+```
+cd ../2/
+```
+
+Создадим deployment c реквестами и лимитами:
+
+```sh
+kubectl apply -f 02-dep.yaml
+```
+
+посмотрим на какой ноде запустилось приложение
+
+```
+NODENAME=$(kubectl get po -o wide -n demo-ns -o=custom-columns=NAME:.metadata.name,node:.spec.nodeName -o json | jq -r .items[0].spec.nodeName)
+kubectl describe node $NODENAME
+```
+
+Увидим overommit
+
+```
+Allocated resources:
+  (Total limits may be over 100 percent, i.e., overcommitted.)
+  Resource           Requests    Limits
+  --------           --------    ------
+  cpu                660m (16%)  50800m (1295%)
+  memory             196Mi (7%)  103100Mi (3801%)
+  ephemeral-storage  0 (0%)      0 (0%)
+Events:              <none>
+```
+
+Посмотрим соседнюю ноду
+
+```
+$ kubectl get nodes
+NAME                        STATUS   ROLES    AGE    VERSION
+cl14607bcn1714k4v3im-ahyn   Ready    <none>   13d    v1.17.8
+
+$ kubectl describe node cl14607bcn1714k4v3im-ahyn
+```
+В ней нет overcommit
+
+```
+Allocated resources:
+  (Total limits may be over 100 percent, i.e., overcommitted.)
+  Resource           Requests    Limits
+  --------           --------    ------
+  cpu                610m (15%)  800m (20%)
+  memory             132Mi (4%)  700Mi (25%)
+  ephemeral-storage  0 (0%)      0 (0%)
+```
+
+
+Удалим лабу
+
+```
+kubectl delete -f 02-dep.yaml
+```

lesson-6/3/03-dep-hpa.yaml

@@ -0,0 +1,51 @@
+
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: nginx
+  namespace: demo-ns
+  labels:
+    app: nginx
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: nginx
+  template:
+    metadata:
+      name: nginx
+      labels:
+        app: nginx
+    spec:
+      containers:
+      - name: nginx
+        image: k8s.gcr.io/hpa-example
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: nginx
+  namespace: demo-ns
+spec:
+  selector:
+    app: nginx
+  ports:
+    - protocol: TCP
+      port: 80
+      targetPort: 80
+  type: LoadBalancer
+---
+apiVersion: autoscaling/v1
+kind: HorizontalPodAutoscaler
+metadata:
+  name: nginx
+  namespace: demo-ns
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: nginx
+  minReplicas: 1
+  maxReplicas: 3
+  targetCPUUtilizationPercentage: 50

lesson-6/3/03-ns-limitRange.yaml

@@ -0,0 +1,18 @@
+---
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: demo-ns
+---
+apiVersion: v1
+kind: LimitRange
+metadata:
+  name: cpu-limit-range
+  namespace: demo-ns
+spec:
+  limits:
+  - default:
+      cpu: 0.5
+    defaultRequest:
+      cpu: 0.25
+    type: Container

lesson-6/3/Readme.md

@@ -0,0 +1,51 @@
+## HorizontalPodAutoscaler
+```
+cd ../3/
+```
+
+Создадим ns и limitRange  :
+
+```sh
+kubectl apply -f 03-ns-limitRange.yaml
+```
+
+Создадим deployment и HPA
+
+```sh
+kubectl apply -f 03-dep-hpa.yaml
+```
+
+Запустим в окне
+
+```sh
+watch kubectl get pod,svc,hpa -n demo-ns
+```
+
+Посылаем curl по IP адресу балансера
+
+```sh
+URL=$(kubectl get svc nginx -n demo-ns -o json | jq -r .status.loadBalancer.ingress[0].ip)
+while true; do wget -q -O- http://$URL; done
+```
+Отпустим нагрузку
+
+
+Ждем когда деплоймент смаштабируется вверх и порадуемся
+
+Посмотрим лог
+
+```sh
+kubectl describe horizontalpodautoscaler.autoscaling/nginx -n demo-ns
+```
+
+```sh
+Conditions:
+  Type            Status  Reason               Message
+  ----            ------  ------               -------
+  AbleToScale     True    ScaleDownStabilized  recent recommendations were higher than current one, applying the highest recent recommendation
+  ScalingActive   True    ValidMetricFound     the HPA was able to successfully calculate a replica count from cpu resource utilization (percentage of request)
+  ScalingLimited  True    TooManyReplicas      the desired replica count is more than the maximum replica count
+  ```
+
+
+  ## Переходим к следущей лабе