Deploy simple NodeJS apps with kubernetes deployment. At this point, this repo used LoadBalancer type ingress to expose HTTP(s) from outside cluster to communicate with the services inside a cluster.
- Master Node - VPS Ubuntu 18.04 LTS with minimum 2 cores CPU and 2GB RAM
- Worker/Slave Node - VPS Ubuntu 18.04 LTS with minimum 2 cores CPU and 2GB RAM(able to skip validation if using 1GB RAM)
- Docker Image -
metallurgical/nodeexample:v0.0.1(My own sample image which is publicly accessible on docker hub) - Git - To clone this repository inside master node
Installation should be done on both master and worker node
Kubernetes required swap memory set to disable for both master and worker node
sudo swapoff -a
Update server library and so forth
sudo apt-get update
Install docker
sudo apt install docker.io
After done installation, verify docker installation
docker --version
Enable docker services
sudo systemctl enable docker
Start docker services
sudo systemctl start docker
Change default driver for docker from cgroup to systemd
cat > /etc/docker/daemon.json <<EOF
{
"exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m"
},
"storage-driver": "overlay2"
}
EOF
mkdir -p /etc/systemd/system/docker.service.d
# Restart docker.
sudo systemctl daemon-reload
sudo systemctl restart docker
Installations should be done on both master and worker node. For ease of identification, we might need to change the nodes's hostname.
On master node
sudo hostnamectl set-hostname master-node
On worker node
sudo hostnamectl set-hostname slave-node
Installations should be done on both master and worker node.
Add Kubernetes signing key
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add
Add the Xenial Kubernetes repository
sudo apt-add-repository "deb http://apt.kubernetes.io/ kubernetes-xenial main"
Install kubeadm(for interaction with api server)
sudo apt install kubeadm
After installation, check the version number of Kubeadm and also verify the installation through the following command
kubeadm version
This step only for master node, while the worker nodes only need to join the connection
sudo kubeadm init --pod-network-cidr=10.244.0.0/16
# If using 1GB RAM and 1 code CPU, you can skip validation
sudo kubeadm init --pod-network-cidr=10.244.0.0/16 --ignore-preflight-errors=NumCPU
After done (copy join command to use later inside worker node), to start using cluster, run following command as normal user
mkdir -p $HOME/.kube
Copy the configuration
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
Change ownership
sudo chown $(id -u):$(id -g) $HOME/.kube/config
This step only for worker node
Paste kubeadm join command that showing up when setting up master cluster
kubeadm join <master-ip-address>:6443 --token <token> --discovery-token-ca-cert-hash <cert-hash>
Verify successful join command if the output showing
This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.
Run 'kubectl get nodes' on the control-plane to see this node join the cluster
This step only for master node
kubeadm get nodes
The output must showing status in notready state
This step only for master node
This will install kube-apiserver, kube-controller-manager, kube-flannel, kube-proxy and kube-scheduler
sudo kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
After done, verify the installation to see the status
kubectl get pods --all-namespaces
Ensure all the status is running, it may take sometimes to make it running, so please keep issuing the command.
This step only for master node
If everything is ready, up and running, its time to deploy our application. Head over to master CLI, navigate to /var/www/html. Clone this repository and run
# If services still not created and running
kubectl create -f deployments.yaml --validate=false
# If services already running and created
kubectl apply -f deployments.yaml --validate=false
To see the created pods, run
kubectl get pods
You should able to see 3 pods were created. To open in browser, browse using following http://<master-node-ip>:30001 and should see hello world
Currently the deployment services only create 3 replicas, to scaling up issue this command
kubectl scale --replicas=7 deployment/myappdeployment
Kubernetes will spin up 4 more pods based on our configurations.