CKAD-exercises Notes -4 Observability

CKAD-exercises Notes 4

困惑

使用 k explain 查询YAML文件格式的时候，经常把层级弄错，有什么办法么？

层级

- 划线

k explain pod.spec. --recursive|less

/liveness

 livenessProbe     <Object>
         exec   <Object>
            command     <[]string>
         failureThreshold       <integer>
         httpGet        <Object>
            host        <string>
            httpHeaders <[]Object>
               name     <string>
               value    <string>
            path        <string>
            port        <string>
            scheme      <string>
         initialDelaySeconds    <integer>
         periodSeconds  <integer>
         successThreshold       <integer>
         tcpSocket      <Object>
            host        <string>
            port        <string>
         timeoutSeconds <integer>
      name      <string>
      ports     <[]Object>
         containerPort  <integer>
         hostIP <string>
         hostPort       <integer>
         name   <string>
         protocol       <string>

1

livenessProbe: # our probe
      exec: # add this line
        command: # command definition
        - ls # ls command

2

livenessProbe: 
      initialDelaySeconds: 5 # add this line
      periodSeconds: 10 # add this line as well
      exec:
        command:
        - ls

3

readinessProbe: # declare the readiness probe
      httpGet: # add this line
        path: / #
        port: 80 #

Logging

Create a busybox pod that runs 'i=0; while true; do echo "$i: $(date)"; i=$((i+1)); sleep 1; done'. Check its logs

kubectl run busybox --image=busybox --restart=Never -- /bin/sh -c 'i=0; while true; do echo "$i: $(date)"; i=$((i+1)); sleep 1; done'
kubectl logs busybox -f # follow the logs

Create a busybox pod that runs ‘notexist’. Determine if there’s an error (of course there is), see it. In the end, delete the pod forcefully with a 0 grace period

kubectl run busybox --restart=Never --image=busybox -- notexist
kubectl logs busybox # will bring nothing! container never started
kubectl describe po busybox # in the events section, you'll see the error
# also...
kubectl get events | grep -i error # you'll see the error here as well
kubectl delete po busybox --force --grace-period=0

Get CPU/memory utilization for nodes (heapster must be running)

kubectl top nodes