Cấu hình health check ứng dụng Spring Boot với Kubernetes Probes

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

apiVersion: apps/v1
kind: Deployment
metadata:
  name: students-service
  labels:
    app: students-service
spec:
  selector:
    matchLabels:
      app: students-service
  replicas: 3
  template:
    metadata:
      labels:
        app: students-service
    spec:
      containers:
        - name: students-service
          image: thanhnb1/students-service:k8s-probe
          envFrom:
            - configMapRef:
                name: students-cm
          ports:
            - containerPort: 8080

          # Cấu hình readinessProbe.
          readinessProbe:
            httpGet:
              path: /actuator/health/readiness
              port: 8080
            initialDelaySeconds: 15
            periodSeconds: 5
            timeoutSeconds: 30
      restartPolicy: Always

kubectl apply -f k8s/students-deployment-readinessProbe.yaml
deployment.apps/students-service created

kubectl describe po/students-service-77bb86b5c4-grzgc
...
Controlled By:  ReplicaSet/students-service-6f84d655bc
Containers:
  students-service:
    Container ID:   containerd://33c1ddb775c7bce29e9333798c5bddd3bc5d07da1e632d496ee0dea249deabe1
    Image:          thanhnb1/students-service:k8s-probe
    Image ID:       docker.io/thanhnb1/students-service@sha256:d5f7d605f1aed64393df490250f1c66e9147102cf22310835c4961f96184e58c
    Port:           8080/TCP
    Host Port:      0/TCP
    State:          Running
      Started:      Sun, 07 May 2023 00:27:19 +0700
    Ready:          True
    Restart Count:  0

    # Phần cấu hình Readiness Probes.
    # 1. Gửi HTTP request đên api: /actuator/health/readiness
    # 2. Sẽ đợi 15s trước khi thực hiện Readiness Probes lần đầu tiên.
    # 3. Timeout của request là 30s.
    # 4. Thực hiện Readiness Probes sau mỗi 5s.
    # 5. Ngưỡng thành công của Readiness Probes = 1 (gọi api thành công 1 lần thì Readiness Probes thành công).
    # 6. Ngưỡng thất bại của Readiness Probes = 3 (sẽ thực hiên 3 lần, nếu sau 3 lần mà vẫn fail thì Readiness Probes fail).
    Readiness:      http-get http://:8080/actuator/health/readiness delay=15s timeout=30s period=5s #success=1 #failure=3
    Environment Variables from:
      students-cm  ConfigMap  Optional: false
    Environment:   <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-jq67d (ro)
...

2023-05-07 00:33:04.512  INFO 1 --- [nio-8080-exec-7] c.v.k.students.filter.CustomURLFilter    :
LOGGING REQUEST-----------------------------------
[REQUEST-ID]: f5a543c7-e66a-4945-a1ee-d1b2319c7cd9
[PATH]: /actuator/health/readiness
[QUERIES]: null
[HEADERS]:
---host : 10.1.28.83:8080
---user-agent : kube-probe/1.25
---accept : */*
---connection : close

2023-05-07 00:33:04.515  INFO 1 --- [nio-8080-exec-7] c.v.k.students.filter.LoggingService     :
LOGGING RESPONSE-----------------------------------
[REQUEST-ID]: f5a543c7-e66a-4945-a1ee-d1b2319c7cd9
[BODY RESPONSE]:
{"status":"UP"}
LOGGING RESPONSE-----------------------------------

apiVersion: apps/v1
kind: Deployment
metadata:
  name: students-service
  labels:
    app: students-service
spec:
  selector:
    matchLabels:
      app: students-service
  replicas: 3
  template:
    metadata:
      labels:
        app: students-service
    spec:
      containers:
        - name: students-service
          image: thanhnb1/students-service:k8s-probe
          envFrom:
            - configMapRef:
                name: students-cm
          ports:
            - containerPort: 8080
          livenessProbe:
            httpGet:
              path: /actuator/health/liveness
              port: 8080
            initialDelaySeconds: 15
            periodSeconds: 5
            timeoutSeconds: 30
      restartPolicy: Always

kubectl apply -f k8s/students-deployment-livenessProbe.yaml
deployment.apps/students-service created

kubectl describe po/students-service-55b5d74ff5
...
Controlled By:  ReplicaSet/students-service-55b5d74ff5
Containers:
  students-service:
    Container ID:   containerd://9f354decc375fe42793ac91eaea77d385278f6dff09d2158a0e317d271a714b2
    Image:          thanhnb1/students-service:loop
    Image ID:       docker.io/thanhnb1/students-service@sha256:e4959a294f3d1b08c1eac02b5d81ef2d82f5b650650579bdf694e490f521fe51
    Port:           8080/TCP
    Host Port:      0/TCP
    State:          Running
      Started:      Tue, 16 May 2023 00:28:42 +0700
    Ready:          True
    Restart Count:  0

    # Phần cấu hình Liveness Probes.
    # 1. Gửi HTTP request đên api: /actuator/health/liveness
    # 2. Sẽ đợi 15s trước khi thực hiện Liveness Probes lần đầu tiên.
    # 3. Timeout của request là 30s.
    # 4. Thực hiện Liveness Probes sau mỗi 5s.
    # 5. Ngưỡng thành công của Liveness Probes = 1 (gọi api thành công 1 lần thì Liveness Probes thành công).
    # 6. Ngưỡng thất bại của Liveness Probes = 3 (sẽ thực hiên 3 lần, nếu sau 3 lần mà vẫn fail thì Liveness Probes fail).
    Liveness:       http-get http://:8080/actuator/health/liveness delay=15s timeout=30s period=5s #success=1 #failure=3
    Environment Variables from:
      students-cm  ConfigMap  Optional: false
    Environment:   <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-n764x (ro)
...

2023-05-16 00:57:51.677  INFO 1 --- [nio-8080-exec-7] c.v.k.students.filter.CustomURLFilter    :
LOGGING REQUEST-----------------------------------
[REQUEST-ID]: 78f9b6e6-a879-4a0a-b815-793f65c15303
[PATH]: /actuator/health/liveness
[QUERIES]: null
[HEADERS]:
---host : 10.1.28.106:8080
---user-agent : kube-probe/1.25
---accept : */*
---connection : close

2023-05-16 00:57:51.679  INFO 1 --- [nio-8080-exec-7] c.v.k.students.filter.LoggingService     :
LOGGING RESPONSE-----------------------------------
[REQUEST-ID]: 78f9b6e6-a879-4a0a-b815-793f65c15303
[BODY RESPONSE]:
{"status":"UP"}
LOGGING RESPONSE-----------------------------------

apiVersion: apps/v1
kind: Deployment
metadata:
  name: students-service
  labels:
    app: students-service
spec:
  selector:
    matchLabels:
      app: students-service
  replicas: 3
  template:
    metadata:
      labels:
        app: students-service
    spec:
      containers:
        - name: students-service
          image: thanhnb1/students-service:k8s-probe
          envFrom:
            - configMapRef:
                name: students-cm
          ports:
            - containerPort: 8080

          # Cấu hình startupProbe.
          startupProbe:
            httpGet:
              path: /actuator/health
              port: 8080
            failureThreshold: 30
            periodSeconds: 10
      restartPolicy: Always

kubectl apply -f k8s/students-deployment-startupProbe.yaml
deployment.apps/students-service created

Controlled By:  ReplicaSet/students-service-69698798c6
Containers:
  students-service:
    Container ID:   containerd://8374c1e9ae4b70fadc24be6a95781b12830a78cd25b02dc0f0941e065f9b5c34
    Image:          thanhnb1/students-service:k8s-probe
    Image ID:       docker.io/thanhnb1/students-service@sha256:d5f7d605f1aed64393df490250f1c66e9147102cf22310835c4961f96184e58c
    Port:           8080/TCP
    Host Port:      0/TCP
    State:          Running
      Started:      Tue, 16 May 2023 01:16:38 +0700
    Ready:          True
    Restart Count:  0

    # Phần cấu hình Startup Probes.
    # 1. Gửi HTTP request đên api: /actuator/health
    # 2. Sẽ đợi 0s trước khi thực hiện Startup Probes lần đầu tiên.
    # 3. Timeout của request là 1s.
    # 4. Thực hiện Startup Probes sau mỗi 10s.
    # 5. Ngưỡng thành công của Startup Probes = 1 (gọi api thành công 1 lần thì Startup Probes thành công).
    # 6. Ngưỡng thất bại của Startup Probes = 30 (sẽ thực hiên 3 lần, nếu sau 3 lần mà vẫn fail thì Startup Probes fail).
    # => Ứng dụng sẽ có tối đa period(10) * failure(30) = 300s để khởi động ứng dụng trước khi container bị restart.
    Startup:        http-get http://:8080/actuator/health delay=0s timeout=1s period=10s #success=1 #failure=30
    Environment Variables from:
      students-cm  ConfigMap  Optional: false
    Environment:   <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-p7bvp (ro)

LOGGING REQUEST-----------------------------------
[REQUEST-ID]: 15b599bc-e499-4780-a429-2343f1996aed
[PATH]: /actuator/health
[QUERIES]: null
[HEADERS]:
---host : 10.1.28.126:8080
---user-agent : kube-probe/1.25
---accept : */*
---connection : close

2023-05-16 01:16:47.958  INFO 1 --- [nio-8080-exec-1] c.v.k.students.filter.LoggingService     :
LOGGING RESPONSE-----------------------------------
[REQUEST-ID]: 15b599bc-e499-4780-a429-2343f1996aed
[BODY RESPONSE]:
{"status":"UP","groups":["liveness","readiness"]}
LOGGING RESPONSE-----------------------------------