Wednesday 26/07/2017
tl;dr - Kubernetes is a container orchestration engine.
tl;dr - Microservices are software components that are independently deployable and scalable.
Kubeadm Documentation : https://kubernetes.io/docs/getting-started-guides/kubeadm/
Provision three or four Ubuntu droplets on Digital Ocean.
Distribution : Ubuntu 16.04.2 x64 ($5 or $10 or $20)
I find the $20 droplets have the best performance for this exercise.
Don't forget to add your SSH key.
If you want to use Digital Ocean for this exercise, use this referral link to get $10 in credit.
Referral Link : https://m.do.co/c/ac62c560d54a
This example assumes Ubuntu as the Operating system for the Masters and Workers.
On master and workers : ubuntu-1gb-sgp1-01/ubuntu-1gb-sgp1-02/ubuntu-1gb-sgp1-03
apt-get update && apt-get install -y apt-transport-https
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -
cat <<EOF >/etc/apt/sources.list.d/kubernetes.list
deb http://apt.kubernetes.io/ kubernetes-xenial main
EOF
apt-get update
apt-get install -y docker.io
apt-get install -y kubelet kubeadm kubectl kubernetes-cni
On master : ubuntu-1gb-sgp1-01
kubeadm init
Starting in Version 1.8, tokens will expire after 24 hours by default (if you require a non-expiring token use --token-ttl 0)
kubeadm init --token-ttl 0
(Grab the final output of this command to add the worker nodes in the kubeadm join section below)
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
Install the overlay network :
kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d '\n')"
On workers : ubuntu-1gb-sgp1-02 / ubuntu-1gb-sgp1-03
sudo su -
kubeadm join --token=<token> <master-ip> --skip-preflight-checks
In separate terminal execute this to watch the status of the kubernetes services.
watch -t -n1 'echo kube-system Pods && kubectl get pods -o wide -n kube-system && echo && echo kube-system Services && kubectl get svc -n kube-system && echo && echo Nodes && kubectl get nodes -o wide'
Only do this part if you want to deploy a sample microservices sample application.
Socks Shop Documentation : https://microservices-demo.github.io/
On Master - ubuntu-1gb-sgp1-01
kubectl create namespace sock-shop
kubectl apply -n sock-shop -f "https://github.com/microservices-demo/microservices-demo/blob/master/deploy/kubernetes/complete-demo.yaml?raw=true"
kubectl get pods -n sock-shop -w
In separate terminal execute this to watch the status of the socks shop application.
watch -t -n1 'echo sock-shop Pods && kubectl get pods -n sock-shop -o wide && echo && echo sock-shop Services && kubectl get svc -n sock-shop && echo && echo Nodes && kubectl get nodes -o wide'
Shock Shop UI = On any worker node (ubuntu-1gb-sgp1-02 or ubuntu-1gb-sgp1-03) ip a | grep eth0 + 30000 range port from kubectl get svc
On any worker node get the IP address : ip a | grep eth0
On master get the port of the front-end service : kubectl get svc -n sock-shop | grep front-end
User ID's and Passwords to access the Socks Shop Application.
Username and Passwords : user password user1 password Eve_Berger eve
kubectl apply -f 'https://cloud.weave.works/launch/k8s/weavescope.yaml?service-token=<token>'
Bash script to tail Kubernetes logs from multiple pods at the same time
Link : https://github.com/johanhaleby/kubetail
wget https://raw.githubusercontent.com/johanhaleby/kubetail/master/kubetail
chmod +x kubetail
kubectl get pods -n sock-shop
./kubetail cart -n sock-shop
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