Monitoring: Monior Applications with top, Monitor Events Pod specific and Cluster wide, Container STDOUT and STDERR Logs #
Create Example Multi-Container Pod #
Alternative run a pod with several containers
# Create a manifest for the pod
vi example-pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: example-pod
spec:
containers:
- name: nginx
image: nginx
- name: busybox
image: busybox
command: ["sleep", "3600"]
# Create the pod
kubectl create -f example-pod.yaml
Monitoring the Resource Usage #
Pod & Containers Inside Pod #
# List pod metrics
kubectl top pod example-pod
# Shell output:
NAME CPU(cores) MEMORY(bytes)
example-pod 0m 4Mi
# List pod metrics: For containers inside the pod
kubectl top pod example-pod --containers
# Shell output:
POD NAME CPU(cores) MEMORY(bytes)
example-pod busybox 0m 0Mi
example-pod nginx 0m 4Mi
Namespace Specific #
# List pod metrics: Specific namespace
kubectl top pod -n default
# List pod metrics: All namespaces
kubectl top pod -A
Sort by CPU or Memory #
# List pod metrics: Sort by CPU usage (default namespace)
kubectl top pod --sort-by=cpu
# List pod metrics: Sort by memory usage (default namespace)
kubectl top pod --sort-by=memory
Example: List all Pods, Sorted by CPU Consumption, Output to File #
# List all pods in the cluster, sorted by highest CPU consumption, save to file
kubectl top pod -A --sort-by=cpu > max-cpu-pods
Kubernetes Events #
Pod Specific #
# List pod details
kubectl describe pod example-pod
# Shell output:
...
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 15s default-scheduler Successfully assigned default/example-pod to ubuntu3
Normal Pulling 15s kubelet Pulling image "nginx"
Normal Pulled 13s kubelet Successfully pulled image "nginx" in 1.022s (1.022s including waiting). Image size: 72955450 bytes.
Normal Created 13s kubelet Created container nginx
Normal Started 13s kubelet Started container nginx
Normal Pulling 13s kubelet Pulling image "busybox"
Normal Pulled 13s kubelet Successfully pulled image "busybox" in 930ms (930ms including waiting). Image size: 2166802 bytes.
Normal Created 12s kubelet Created container busybox
Normal Started 12s kubelet Started container busybox
Namespace & Cluster Wide #
Watch & Sort #
# List events: In default namespace
kubectl get events
# Follow events
kubectl get events --watch
# List events: Sort by creation time
kubectl get events --sort-by=.metadata.creationTimestamp
Specific Namespace #
# List events: Specific namespace
kubectl get events -n namespace-name
# List events: All namespaces
kubectl get events -A
Kubernetes Logs #
Example Pod #
The following Busybox container container1 will print the date every second to the standard output stream STDOUT:
# Create a manifest for the pod
vi log-pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: log-pod
spec:
containers:
- name: container1
image: busybox:1.28
args:
- /bin/sh
- -c
- 'while true; do echo "$(date)"; sleep 1; done'
- name: nginx
image: nginx:latest
# Create the pod
kubectl create -f log-pod.yaml
Container STDOUT and STDERR Logs #
List Logs of Pod and Specific Container #
# List logs of a pod
kubectl logs log-pod
# List logs of a pod: Specific container
kubectl logs log-pod -c container1
# Follow the logs of a pod
kubectl logs -f log-pod
Sort with Time #
# List logs of a pod: Last 10 seconds
kubectl logs log-pod --since=10s
# Shell output:
Tue Nov 12 11:47:25 UTC 2024
Tue Nov 12 11:47:26 UTC 2024
Tue Nov 12 11:47:27 UTC 2024
Tue Nov 12 11:47:28 UTC 2024
Tue Nov 12 11:47:29 UTC 2024
Tue Nov 12 11:47:30 UTC 2024
Tue Nov 12 11:47:31 UTC 2024
Tue Nov 12 11:47:32 UTC 2024
Tue Nov 12 11:47:33 UTC 2024
Tue Nov 12 11:47:34 UTC 2024
Note: Use s for seconds, m for minutes and h for hours.
More Logs Commands #
# List more logs commands
kubectl logs --help