Kubernetes

Useful

alias:

alias k="kubectl"
alias ks="kubectl --namespace kube-system"
alias ke="kubectl get events --sort-by='{.lastTimestamp}'"

dump all :

kubectl get all --export=true -o yaml

list form:

k get pods
k get rs # replica set
k get rc # replication controller

what are all the things ?

kubectl api-resources

event sorted by time

kubectl get events --sort-by=.metadata.creationTimestamp

what storage classes does my cluster support?

k get storageclass

audit: who tried to do what?

ks get pod | grep kube-apiserver-ip

ks logs $podname

who tried to scale unsuccessfully?

ks logs $podname | grep scale | grep cloud | awk '$8!=200{print $0}'

Where is the service account token that I gave this pod?

It's in here: /var/run/secrets/kubernetes.io/serviceaccount/token

=== Manually edit the replicas of a deployment from within the same namespace, but a different pod.

export API_URL="https://${KUBERNETES_SERVICE_HOST}:${KUBERNETES_SERVICE_PORT}/${KUBE_ENDPOINT}"
export TOKEN=`cat /var/run/secrets/kubernetes.io/serviceaccount/token`
export CURL_CA_BUNDLE=/var/run/secrets/kubernetes.io/serviceaccount/ca.crt

curl \
 -H 'Accept: application/json' \
 -H "Authorization: Bearer $TOKEN" \
 $API_URL \
 > scale.json
# edit scale.json, set replicas to 4
curl -X PUT \
 -d@scale.json \
 -H 'Content-Type: application/json' \
 -H "Authorization: Bearer $TOKEN" \
 $API_URL

This was the role that did it ( FIXME) ,par it down .

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: kube-cloudwatch-autoscaler
  labels:
    app: kube-cloudwatch-autoscaler
rules:
- apiGroups:
  - ""
  resources:
  - nodes
  verbs:
  - list
- apiGroups:
  - apps
  resources:
  - deployments
  - deployments.apps
  - deployments.apps/scale
  - "*/scale"
  verbs:
  - get
  - update
  - patch
  - put
- apiGroups:
  - ""
  resources:
  - configmaps
  verbs:
  - get
  - create

metricss

wget "$(kubectl config view -o jsonpath='{range .clusters[*]}{@.cluster.server}{"\n"}{end}')"

Practices and Guidlines

Do not use replication controllers, instead use replica sets

Cgroup / slice errors

https://github.com/kubernetes/kubernetes/issues/56850

log message:

Sep 18 21:32:37 ip-10-10-37-50 kubelet[1681]: E0918 21:32:37.901058    1681 summary.go:92] Failed to get system container stats for "/system.slice/docker.service": failed to get cgroup stats for "/system.slice/docker.service": failed to get container info for "/system.slice/docker.service": unknown container "/system.slice/docker.service"