dev_tips.md

TODO

• https://github.com/kubernetes/examples/tree/master/staging/https-nginx
• https://kubernetes.io/docs/tasks/access-application-cluster/web-ui-dashboard/
• https://www.digitalocean.com/community/tutorials/how-to-install-software-on-kubernetes-clusters-with-the-helm-package-manager
  • https://helm.sh/

K8S BEARER TOKEN example

kubectl get sa kubernetes-dashboard -n kube-system -o json | jq -rC '.secrets'
kubectl get secret kubernetes-dashboard-token-hvjww -n kube-system -o json | jq -rC '.data.token'

kubectl create serviceaccount jenkins
kubectl get serviceaccounts jenkins -o yaml
kubectl get secret jenkins-token-1yvwg -o yaml

update haproxy

kubectl get svc appsvc1 -o json | jq -jC '.spec.ports[0].nodePort'
kubectl get svc appsvc1 -o json | jq -jC '.spec.ports[0].targetPort'

{
  "appsvc1": [
    {
      "nodePort": "80",
      "targetPort": "30608"
    },
    {
      "nodePort": "443",
      "targetPort": "30609"
    }
  ]
}



kubectl get nodes -o json | jq -j '.items[0].status.addresses[0].address'
kubectl get nodes -o json | jq -j '.items[0].metadata.name'

{
  "workers": [
    {
      "ip": "10.132.0.16",
      "name": "k8s-test-worker-002"
    },
    {
      "ip": "10.132.0.15",
      "name": "k8s-test-worker-001"
    }
  ]
}



sudo apt-get install -y python3-setuptools python3-pip python3-virtualenv ipython3
#sudo apt-get install -y python-setuptools python-pip python-virtualenv ipython
#sudo pip install kubernetes



k8s_ports="kubectl get svc appsvc1 -o json"
k8s_ips="kubectl get nodes -o json"

import subprocess,json

stdout_json = json.loads(subprocess.getoutput(k8s_ports))
print (stdout_json['spec']['ports'][0]['nodePort'])
print (stdout_json['spec']['ports'][0]['targetPort'])

stdout_json = json.loads(subprocess.getoutput(k8s_ips))
print (stdout_json['items'][0]['status']['addresses'][0]['address'])
print (stdout_json['items'][0]['metadata']['name'])

new_array = [] new_array.append({ "nodePort": stdout_json['spec']['ports'][0]['nodePort'], "targetPort": stdout_json['spec']['ports'][0]['targetPort'] })

new_dict = {"appsvc1": new_array}

Ingress

• https://kubernetes.github.io/ingress-nginx/
• image: quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.19.0

minikube

option 1

minikube ssh
ssh -i $(minikube ssh-key) docker@$(minikube ip)
ssh -i ~/.minikube/machines/minikube/id_rsa docker@$(minikube ip)

option 2

• Setup MiniKube environment

minikube start
minikube ssh

• Inside MiniKube instance

mkdir -p /data/k8s
echo 'Hello from Kubernetes storage' > /data/k8s/index.html
exit

option 3

tmux new-session -d -s "minikube" \
    minikube mount $(pwd):/data/k8s

tmux kill-session -t minikube

k8s volumes

--runtime-config=storage.k8s.io/v1=true ??

• examples: https://github.com/kubernetes/examples/tree/master/staging/volumes

glusterfs

• general vars

S_FOLDER=/data/k8
C_FOLDER=/data/k8_hook
GNAME=gfs
GSERVER=gserver

• single node server

sed -i "s|^127.0.0.1.*|& $GSERVER|m" /etc/hosts
mkdir -p $S_FOLDER
gluster volume create $GNAME $GSERVER:$S_FOLDER force
gluster volume start $GNAME
gluster volume info
gluster volume status $GNAME detail

• multiple node server

gluster peer probe <new_server>
gluster peer status
...
gluster volume create $GNAME replica <num> $GSERVER1:$S_FOLDER $GSERVER2:$S_FOLDER force

• in client

echo "192.168.39.1    gserver" | sudo tee -a /etc/hosts
# echo "192.168.32.10    gserver" | sudo tee -a /etc/hosts
mkdir -p $C_FOLDER
sudo mount -t glusterfs $GSERVER:/$GNAME $C_FOLDER
for i in `seq -w 1 100`; do cp -rp /var/log/kern.log $C_FOLDER/copy-test-$i; done

links: https://docs.openshift.com/container-platform/3.9/install_config/storage_examples/gluster_example.html

gluster

C_FOLDER=/data/k8_hook
GNAME=gfs
GSERVER=gserver
mkdir -p $C_FOLDER
sudo mount -t glusterfs $GSERVER:/$GNAME $C_FOLDER
ls /data/k8_hook

k8s

• Create

kubectl create deploy nginx --image=nginx
kubectl expose deploy nginx --port 80 --target-port 80 --type NodePort --name=mynginx
watch kubectl get services
# curl http://192.168.32.12:nginx_port

• Apply

kubectl apply -f pv-glusterfs/ep-glusterfs.yaml
kubectl apply -f pv-glusterfs/pv-glusterfs.yaml
kubectl apply -f pv-glusterfs/pvc-glusterfs.yaml
kubectl apply -f pv-glusterfs/nginx-deployment-pvc_glusterfs.yaml
kubectl apply -f output/nginx-service_LoadBalancer.yaml

• Delete

kubectl delete ep glusterfs-ep && kubectl delete svc glusterfs-ep
kubectl delete pv gluster-pv
kubectl delete pvc gluster-pvc
kubectl delete deploy nginx
kubectl delete svc mynginx

• View

kubectl get deploy,ep,pv,pvc
kubectl get svc
kubectl get nodes

links

• StorageClass: https://kubernetes.io/docs/concepts/storage/storage-classes/