kubernetes
### notes ###
cheat sheet source - https://github.com/dennyzhang/cheatsheet-kubernetes-A4
Common Commands
Events & Metrics
| Name | Command |
|---|---|
| View all events | kubectl get events --all-namespaces |
| List Events sorted by timestamp | kubectl get events –sort-by=.metadata.creationTimestamp |
Node Maintenance
| Name | Command |
|---|---|
| Mark node as unschedulable | kubectl cordon $NDOE_NAME |
| Mark node as schedulable | kubectl uncordon $NDOE_NAME |
| Drain node in preparation for maintenance | kubectl drain $NODE_NAME |
Namespace & Security
| Name | Command |
|---|---|
| List authenticated contexts | kubectl config get-contexts, ~/.kube/config |
| Set namespace preference | kubectl config set-context <context_name> --namespace=<ns_name> |
| Load context from config file | kubectl get cs --kubeconfig kube_config.yml |
| Switch context | kubectl config use-context <cluster-name> |
| Delete the specified context | kubectl config delete-context <cluster-name> |
| List all namespaces defined | kubectl get namespaces |
| List certificates | kubectl get csr |
| Check user privilege | kubectl –as=system:serviceaccount:ns-denny:test-privileged-sa -n ns-denny auth can-i use pods/list |
| Check user privilege | kubectl auth can-i use pods/list |
| Reference | Link: kubernetes yaml templates |
Network
| Name | Command |
|---|---|
| Temporarily add a port-forwarding | kubectl port-forward redis-134 6379:6379 |
| Add port-forwaring for deployment | kubectl port-forward deployment/redis-master 6379:6379 |
| Add port-forwaring for replicaset | kubectl port-forward rs/redis-master 6379:6379 |
| Add port-forwaring for service | kubectl port-forward svc/redis-master 6379:6379 |
| Get network policy | kubectl get NetworkPolicy |
Patch
| Name | Summary |
|---|---|
| Patch service to loadbalancer | kubectl patch svc $svc_name -p '{"spec": {"type": "LoadBalancer"}}' |
Extenstions
| Name | Summary |
|---|---|
| Enumerates the resource types available | kubectl api-resources |
| List api group | kubectl api-versions |
| List all CRD | kubectl get crd |
| List storageclass | kubectl get storageclass |
Components & Services
Services on Master Nodes
| Name | Summary |
|---|---|
| kube-apiserver | exposes the Kubernetes API from master nodes |
| etcd | reliable data store for all k8s cluster data |
| kube-scheduler | schedule pods to run on selected nodes |
| kube-controller-manager | node controller, replication controller, endpoints controller, and service account & token controllers |
Services on Worker Nodes
| Name | Summary |
|---|---|
| kubelet | makes sure that containers are running in a pod |
| kube-proxy | perform connection forwarding |
| Container Runtime | Kubernetes supported runtimes: Docker, rkt, runc and any OCI runtime-spec implementation. |
Addons: pods and services that implement cluster features
| Name | Summary |
|---|---|
| DNS | serves DNS records for Kubernetes services |
| Web UI | a general purpose, web-based UI for Kubernetes clusters |
| Container Resource Monitoring | collect, store and serve container metrics |
| Cluster-level Logging | save container logs to a central log store with search/browsing interface |
Tools
| Name | Summary |
|---|---|
| kubectl | the command line util to talk to k8s cluster |
| kubeadm | the command to bootstrap the cluster |
| kubefed | the command line to control a Kubernetes Cluster Federation |
| Kubernetes Components | Link: Kubernetes Components |