Observability

Observability
--------------

Readiness probes
---

POD Status : Pending, ContainerCreating, Running
POD Conditions: PodScheduled, Initialized, ContainersReady, Ready


apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: simple-webapp
  name: simple-webapp
spec:
  containers:
  - image: simple-webapp
    name: simple-webapp
    ports:
      - containerPort: 8080
    readinessProbe:
      httpGet:
        path: /api/ready
        port: 8080
      initialDelaySeconds: 10
      periodSeconds: 5

For TCP probes

readinessProbe:
  tcpSocket:
    port: 3306

For command

readinessProbe:
  exec:
    command:
      - cat
      - /app/is_ready

initialDelaySeconds: 10 - this is to specify how much time for warmup
periodSeconds: 5 - delay between two probes
failureThreshold: 8 - number of times the probes should retry


Liveness probes
---

apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: simple-webapp
  name: simple-webapp
spec:
  containers:
  - image: simple-webapp
    name: simple-webapp
    ports:
      - containerPort: 8080
    livenessProbe:
      httpGet:
        path: /api/ready
        port: 8080
      initialDelaySeconds: 10
      periodSeconds: 5
      failureThreshold: 8

For TCP probes

livenessProbe:
  tcpSocket:
    port: 3306

For command

livenessProbe:
  exec:
    command:
      - cat
      - /app/is_ready



Logging
---

apiVersion: v1
kind: Pod
metadata:
  name: event-simulator-pod
spec:
  containers:
  - image: event-simulator
    name: kodekloud/event-simulator
  - image: image-processsor
    name: some-image-processor

For multiple containers within a pod, you must specify the name of the conainter


 Monitoring
 ---


 metric-server can be instaled through a git clone of a repository

 Then launch a simple : kubectl create -f deploy/1.8/app

 then you can use the following commands:

  > kubectl top nodes

  > kubectl top pods