k8s-demo

Hit kubernetes, to bootstrap kubernetes you can check k8s on ubuntu with Vagrant and Ansible or use kubeadm

Run, show, scale and expose to public

 kubectl create namespace infra
 kubectl create namespace green-dev
 kubectl label node 172.9.8.51 role=ingress
 kubectl create -f ./deploy/ingress.yaml
 # for more details about exposed metrics [check](https://github.com/kubernetes/kube-state-metrics#metrics)
 kubectl create -f ./deploy/kube-state-metrics.yaml
 # prometheus configuration is based on official [sample](https://github.com/prometheus/prometheus/blob/master/documentation/examples/prometheus-kubernetes.yml)
 kubectl create  -f ./deploy/prometheus.yaml
 kubectl create  -f ./deploy/prometheus-node-exporter.yaml
 kubectl create  -f ./deploy/grafana.yaml
 # elasticsearch
 kubectl create  -f ./deploy/es.yaml
 # Need to configure env SLACK_WEBHOOK_URL and SLACK_CHANNEL otherwise use waleedsamy/k8s-fluentd-nodejs-winston:v1.0 instead
 kubectl create -f ./deploy/fluentd-daemonSet.yaml
 kubectl create -f ./deploy/hello.yaml
 kubectl create  -f ./deploy/kibana.yaml

View your cluster

# run weavescope on k8s, check Utils for port forwarding to be able to access from your browser
kubectl create -f 'https://cloud.weave.works/launch/k8s/weavescope.yaml' --validate=false

Utils

# get inside a container
kubectl exec -it {container} -- bash
# curl without need to update your /etc/hosts
curl -H 'Host: foo.example.com' --resolve foo.example.com:80:127.0.0.1 http://foo.example.com/
# run busybox in your cluster
kubectl run -i --tty busybox --image=busybox --restart=Never -- sh; kubectl delete po busybox
$ nslookup kubernetes
# run bind-tools in your cluster, usually i use it to check if DNS work correclt
kubectl run -i --tty bind-tools --image=lherrera/bind-tools --restart=Never -- sh; kubectl delete po bind-tools
$ host -t A kubernetes
# run curl
kubectl run -i --tty curl --image=radial/busyboxplus:curl
# port forward to pod, you now can access it as if it is running in your machine, usually use it if I need to access service in my browser
kubectl port-forward {pod} 4040
# select pod name
kubectl get pod --selector=weavescope-component=weavescope-app -o jsonpath='{.items..metadata.name}'
# forward port to prometheus pod
kubectl --namespace=infra get pods -l app=prometheus -o name | \
	sed 's/^.*\///' | \
	xargs -I{} kubectl --namespace=infra port-forward {} 9090:9090
# access kubernetes from a pod using default serviceaccount
curl --cacert /var/run/secrets/kubernetes.io/serviceaccount/ca.crt  -H "Authorization: Bearer $(cat /var/run/secrets/kubernetes.io/serviceaccount/token)" https://kubernetes.default.svc.cluster.local

# when creating container with --net-alias, it can be reached with this name from other containers in the same network
docker network create green
docker run -d --net=green --net-alias web nginx:alpine
docker run --rm --net green lherrera/bind-tools host -t A web
docker run --rm --net green lherrera/bind-tools ping web

Notes:

• kubernetes service should has prometheus.io/probe with value of true to be scraped

• kubernetes pod scraping is configured by:

  • prometheus.io/scrape: Only scrape pods that have a value of true
  • prometheus.io/path: If the metrics path is not /metrics override this.
  • prometheus.io/port: Scrape the pod on the indicated port instead of the default of 9102.

• resources:

• http://blog.oestrich.org/2016/01/nodeport-kubernetes-load-balancer/