#!/bin/sh

# 1st Step - Ask user for no. of cluster nodes
echo "How many nodes would you like your cluster to have?"
read NODECOUNT

# 2nd Step - Ask user for node details & store in tmp files
for ((i=0; i < $NODECOUNT; i++))
do
    echo "Please enter the IP address of the ${i}th node: "
    read IPADDR_$i
    echo "${IPADDR_$i}" > /tmp/node${i}_ip.txt
    
    echo "Please enter the username for SSH access to the ${i}th node (defaults to 'root'):"
    read USERNAME_$i
    if [ -z $USERNAME ] 
        then USERNAME="root"; 
    fi
    echo "${USERNAME}" > /tmp/node${i}_user.txt
    
    echo "Please enter the password for SSH access to the ${i}th node (defaults to 'root'):"
    read PASSWORD_$i
    if [ -z $PASSWORD ] 
        then PASSWORD="root"; 
    fi
    echo "${PASSWORD}" > /tmp/node${i}_pass.txt
done

# 3rd Step - Confirm node details with user & allow them to edit if necessary
echo "The following IP addresses were entered by the user:"
for ((i=0; i < $NODECOUNT; i++))
do
    echo "${IPADDR_$i}"
done
read -p "Please confirm these are correct, or type 'edit' to make changes: " USERCONFIRMATION
if [ "$USERCONFIRMATION" == "edit" ] 
then
    for ((i=0; i < $NODECOUNT; i++))
        do
            echo "Please enter the IP address of the ${i}th node: "
            read IPADDR_$i
            echo "${IPADDR_$i}" > /tmp/node${i}_ip.txt
            
            echo "Please enter the username for SSH access to the ${i}th node (defaults to 'root'):"
            read USERNAME_$i
            if [ -z $USERNAME ] 
                then USERNAME="root"; 
            fi
            echo "${USERNAME}" > /tmp/node${i}_user.txt
            
            echo "Please enter the password for SSH access to the ${i}th node (defaults to 'root'):"
            read PASSWORD_$<s>        i
            if [ -z $PASSWORD ] 
                then PASSWORD="root"; 
            fi
            echo "${PASSWORD}" > /tmp/node${i}_pass.txt
        done
fi

# 4th Step - Ask user to define master node & store selection in tmp files
echo "Please enter the number of the node you would like to define as your control plane (master):"
read MASTERNODE_SELECTION
echo "${MASTERNODE_SELECTION}" > /tmp/master.txt

# 5th Step - Add K8S repo & relevant keys to each node, install K8S & restart services
for ((i=0; i < $NODECOUNT; i++))
do
    echo "Adding Kubernetes repo to the system sources list on ${IPADDR_$i}..."
    ssh -n $USERNAME_$i@${IPADDR_$i} 'sudo sh -c "echo deb http://apt.kubernetes.io/ kubernetes-xenial main > /etc/apt/sources.list.d/kubernetes.list"' 
    
    echo "Adding GPG key to the system on ${IPADDR_$i}..."
    ssh -n $USERNAME_$i@${IPADDR_$i} 'sudo curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -'
    
    echo "Updating package list on ${IPADDR_$i}..."
    ssh -n $USERNAME_$i@${IPADDR_$i} 'sudo sh -c "apt update"'
    
    echo "Upgrading packages on ${IPADDR_$i}..."
    ssh -n $USERNAME_$i@${IPADDR_$i} 'sudo sh -c "apt upgrade"'
done

# 6th Step - Install K8S on master node and ask for configuration options from user
echo "Installing Kubernetes on the master node..."
ssh -n $USERNAME_$MASTERNODE_SELECTION@${IPADDR_$MASTERNODE_SELECTION} 'sudo sh -c "apt install kubeadm; apt-get install kubelet; apt-get install kubernetes-cni"'
    
echo "Please enter your preferred port number for the control plane (master node) (defaults to 6443): "
read PORT_SELECTION
if [ -z $PORT_SELECTION ] 
    then PORT_SELECTION="6443"; 
fi
    
echo "Please enter your preferred IP address or FQDN for the control plane (master node) (defaults to '0.0.0.0'): "
read IPADDRESS_SELECTION
if [ -z $IPADDRESS_SELECTION ] 
    then IPADDRESS_SELECTION="0.0.0.0"; 
fi
    
echo "Configuring Kubernetes on the master node, using port ${PORT_SELECTION} and listening IP/domain ${IPADDRESS_SELECTION}..."
ssh -n $USERNAME_$MASTERNODE_SELECTION@${IPADDR_$MASTERNODE_SELECTION} 'sudo sh -c "kubeadm init --apiserver-advertise-address=$IPADDRESS_SELECTION --apiserver-bind-port=$PORT_SELECTION"'
    
echo "Please enter the following options to configure the Kubernetes control plane (master node)..."
echo "1. Pod Network CIDR: "
read NETWORKCIDR_SELECTION
echo "${NETWORKCIDR_SELECTION}" > /tmp/network.txt
    
echo "2. Service Subnet: "
read SERVICESUBNET_SELECTION
echo "${SERVICESUBNET_SELECTION}" > /tmp/servicesubnet.txt
    
echo "3. Kubernetes DNS Domain: "
read K8SDNS_SELECTION
echo "${K8SDNS_SELECTION}" > /tmp/kube-dns.txt
    
echo "Please enter your preferred Kubernetes version (defaults to '1.20.1'): "
read K8SVERSION_SELECTION
if [ -z $K8SVERSION_SELECTION ] 
    then K8SVERSION_SELECTION="1.20.1"; 
fi
    
echo "Please enter your preferred pod Network provider (defaults to 'calico'): "
read NETWORKPROVIDER_SELECTION
if [ -z $NETWORKPROVIDER_SELECT<s>	    ION_SELECTION ] 
    then NETWORKPROVIDER_SELECTION="calico"; 
fi
    
echo "Configuring Kubernetes on the master node with pod Network CIDR: ${NETWORKCIDR_SELECTION}, service subnet: ${SERVICESUBNET_SELECTION}, K8S DNS domain: ${K8SDNS_SELECTION}, K8S version: ${K8SVERSION_SELECTION}, and pod network provider: ${NETWORKPROVIDER_SELECTION}..."
ssh -n $USERNAME_$MASTERNODE_SELECTION@${IPADDR_$MASTERNODE_SELECTION} 'sudo sh -c "kubectl apply --kubelet-extra-args '--node-ip=$IPADDRESS_SELECTION' -f https://docs.projectcalico.org/manifests/kube-flannel.yaml; kubeadm init phase addon all; kubectl apply --kubelet-extra-args '--node-ip=$IPADDRESS_SELECTION' -f https://docs.projectcalico.org/manifests/kube-flannel.yaml; kubectl create deployment nginx-deployment --image=nginx; kubectl expose deployments nginx-deployment --port 80 --type LoadBalancer"'
    
echo "Restarting Kubernetes services on the master node..."
ssh -n $USERNAME_$MASTERNODE_SELECTION@${IPADDR_$MASTERNODE_SELECTION} 'sudo sh -c "systemctl restart kubelet.service"'
    
echo "Restarting Kubernetes services on all nodes..."
for ((i=0; i < $NODECOUNT; i++))
    do
        echo "Restarting Kubernetes services on the ${IPADDR_$i} node..."
        ssh -n $USERNAME_$i@${IPADDR_$i} 'sudo sh -c "systemctl restart kubelet.service"'
    done