# Kubectl Kubernetes CheatSheet

# Common Commands

# Check Performance

# Resources Deletion

# Pod

# Pod Advanced

# Label & Annotations

# Deployment & Scale

# Quota & Limits & Resource

# Service

# StatefulSet

# Volumes & Volume Claims

# Security

# Extenstions

# Components & Services

# Services on Master Nodes

# Services on Worker Nodes

# Tools

# Other Components

# Log files

# Events & Metrics

# Namespace & Security

# Network

# Basic

# Key Concepts

# Kubernetes Critical Files

# Check status

# Names of certificates files

Names of certificates files:

• ca.crt, ca.key (CA certificate)
• apiserver.crt, apiserver.key (API server certificate)
• apiserver-kubelet-client.crt, apiserver-kubelet-client.key (client certificate for the apiservers to connect to the kubelets securely)
• sa.pub, sa.key (a private key for signing ServiceAccount )
• front-proxy-ca.crt, front-proxy-ca.key (CA for the front proxy)
• front-proxy-client.crt, front-proxy-client.key (client cert for the front proxy client)

# Misc scripts

# Tail pod log by label

namespace="mynamespace"
mylabel="app=mylabel"
kubectl get pod -l "$mylabel" -n "$namespace" | tail -n1 \
    | awk -F' ' '{print $1}' | xargs -I{} \
      kubectl logs -n "$namespace" -f {}

# Get node hardware resource utilization

kubectl get nodes --no-headers \
     | awk '{print $1}' | xargs -I {} \
     sh -c 'echo {}; kubectl describe node {} | grep Allocated -A 5'

kubectl get nodes --no-headers | awk '{print $1}' | xargs -I {} \
    sh -c 'echo {}; kubectl describe node {} | grep Allocated -A 5 \
     | grep -ve Event -ve Allocated -ve percent -ve -- ; echo'

# Apply yaml files recursively

# create
time ls -1 */*.yml | grep -v namespace | xargs -I{} kubectl apply -f {}

# delete
time ls -1r */*.yml | grep -v namespace | xargs -I{} kubectl delete -f {}

# Apply the configuration in manifest.yaml and delete all the other configmaps that are not in the file.

kaubectl apply --prune -f manifest.yaml --all --prune-whitelist=core/v1/ConfigMap

# List all critical pods

kubectl --namespace kube-system get pods

for pod in $(kubectl --namespace kube-system get pods -o jsonpath="{.items[*].metadata.name}"); do
    node_info=$(kubectl --namespace kube-system describe pod $pod | grep "Node:")
    echo "Pod: $pod, $node_info"
done

# Helm: The Kubernetes Package Manager

Release, list, inspect, delete, rollback, purge

# Metric Server

Metrics Server is a cluster-wide aggregator of resource usage data. Metrics Server registered in the main API server through Kubernetes aggregator.

Today (Kubernetes 1.7), there are several sources of metrics within a Kubernetes cluster

Today, heapster is the source of the time-series data for the Kubernetes Dashboard. All other Kubernetes components will supply their own metrics in a Prometheus format

In logging domain, we can say syslog is the standard format In metric domain, maybe we can choose prometheus as the standard format.