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馃殌 Vu Dao 馃殌
馃殌 Vu Dao 馃殌

Posted on • Updated on

Launch A Multi-node Kubernetes Cluster Using Vagrant And KVM

What鈥檚 In This Document


馃殌 Create Vagrantfile

Following is to create 1 master + 2 slaves (libvirt driver KVM) and a shared folder between nodes which mounted to /vagrant

# -*- mode: ruby -*-
# vi: set ft=ruby :

VAGRANTFILE_API_VERSION = "2"

Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
    config.vm.provider :libvirt do |libvirt|
        libvirt.driver = "kvm"
    end
    config.vm.synced_folder './shared', '/vagrant', type: '9p', disabled: false, accessmode: "mapped"
    config.vm.box = "generic/ubuntu2004"
    config.vm.box_version = "3.0.6"
    config.vm.network "forwarded_port", guest: 5432, host: 5432
    config.vm.provision:shell, inline: <<-SHELL
        echo "root:rootroot" | sudo chpasswd
        sudo timedatectl set-timezone Asia/Ho_Chi_Minh
    SHELL

    config.vm.define "kube1" do |kube1|
        kube1.vm.hostname = "kube1"
        kube1.vm.network "private_network", ip: "192.168.121.211"
        kube1.vm.provision:shell, inline: <<-SHELL
            sudo echo -e "192.168.121.211\tkube1" >> /etc/hosts
        SHELL
        kube1.vm.provision:shell, path: "kube-bootstrap.sh"
    end

    config.vm.define "kube2" do |kube2|
        kube2.vm.hostname = "kube2"
        kube2.vm.network "private_network", ip: "192.168.121.212"
        kube2.vm.provision:shell, inline: <<-SHELL
            sudo echo -e "192.168.121.212\tkube2" >> /etc/hosts
        SHELL
        kube2.vm.provision:shell, path: "kube-bootstrap.sh"
    end

    config.vm.define "master" do |master|
        master.vm.hostname = "master"
        master.vm.network "private_network", ip: "192.168.121.210"
        master.vm.provision:shell, inline: <<-SHELL
            sudo sed -i 's/127\.0\.1\.1.*master//' /etc/hosts
            sudo echo -e "192.168.121.210\tmaster" >> /etc/hosts
        SHELL
        master.vm.provision:shell, path: "kube-bootstrap.sh"
        master.vm.provision:shell, path: "kubeadm_reinstall.sh"
    end
end
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  • You can configure as many masters and slaves as you like.
# master
kube1.vm.network "private_network", ip: "192.168.121.210"

# kube1
kube1.vm.network "private_network", ip: "192.168.121.211"

# kube2
kube2.vm.network "private_network", ip: "192.168.121.212"
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馃殌 Bootstrap script for master and worker nodes

#!/bin/bash
# Bootstrap machine

ensure_netplan_apply() {
    # First node up assign dhcp IP for eth1, not base on netplan yml
    sleep 5
    sudo netplan apply
}

step=1
step() {
    echo "Step $step $1"
    step=$((step+1))
}

resolve_dns() {
    step "===== Create symlink to /run/systemd/resolve/resolv.conf ====="
    sudo rm /etc/resolv.conf
    sudo ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf
}

install_docker() {
    step "===== Installing docker ====="
    sudo apt update
    sudo apt install -y apt-transport-https ca-certificates curl gnupg-agent software-properties-common
    sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
    sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
    sudo apt update
    sudo apt install -y docker-ce docker-ce-cli containerd.io
    sudo groupadd docker
    sudo gpasswd -a $USER docker
    sudo chmod 777 /var/run/docker.sock
}

install_kube() {
    step "===== Installing kube ====="
    sudo apt-add-repository "deb http://apt.kubernetes.io/ kubernetes-xenial main"
    sudo apt update
    sudo curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add
    sudo apt install -y kubeadm
    sudo swapoff -a
    sudo echo "source <(kubectl completion bash)" >> /home/vagrant/.bashrc
    sudo echo "source <(kubeadm completion bash)" >> /home/vagrant/.bashrc
}

setup_root_login() {
    step "===== Setup root login ====="
    sudo sed -i 's/#PermitRootLogin prohibit-password/PermitRootLogin yes/' /etc/ssh/sshd_config
    sudo systemctl restart ssh
    sudo echo "root:rootroot" | chpasswd
}

setup_welcome_msg() {
    step "===== Bash ====="
    sudo apt -y install cowsay
    sudo echo -e "\necho \"Welcome to Vagrant Kube Ubuntu 18.04\" | cowsay\n" >> /home/vagrant/.bashrc
    sudo ln -s /usr/games/cowsay /usr/local/bin/cowsay
    sudo apt install -y tcl expect net-tools
}

main() {
    ensure_netplan_apply
    resolve_dns
    install_docker
    install_kube
    setup_root_login
    setup_welcome_msg
}

main
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馃殌 Bootstrap a Kubernetes cluster using Kubeadm

#!/bin/bash
# Reset and start kubeadm

echo "Enter password:"
read -s PASSWORD

sudo_expect() {
    command="sudo $1"
    cat > /tmp/tmp.exp <<EOF
#!/usr/bin/expect
set password [lindex \$argv 0]
set cmd [lrange \$argv 1 end]

spawn {*}\$cmd

expect {
    "password" {
        send "\$password\r"
        exp_continue
    }
    "Are you sure you want to proceed?" {
        send "y\r"
        exp_continue
    }
    eof {
        exit
    }
}

interact
EOF

    expect /tmp/tmp.exp $PASSWORD $command
}

resestKubeadm() {
    sudo_expect "kubeadm reset -f"
    sudo_expect "iptables -F"
}

initKubeadm() {
    sudo_expect "swapoff -a"
    if [ "$(hostname)" != "master" ]; then
        sudo_expect "hostname master"
    fi
    sudo_expect "rm -rf /var/lib/etcd/member"
    sudo_expect "kubeadm init --node-name master --apiserver-advertise-address $(hostname -i)"
    mkdir -p $HOME/.kube
    rm -f $HOME/.kube/config
    sudo_expect "cp -i /etc/kubernetes/admin.conf $HOME/.kube/config"
    sudo_expect "chown $(id -u):$(id -g) $HOME/.kube/config"
    sudo_expect "chmod +wr /etc/kubernetes/admin.conf"
}

kubeAddOn() {
    kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d '\n')"
}

resestKubeadm
initKubeadm
kubeAddOn
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馃殌 Join nodes to Kubernetes cluster

#!/bin/bash
# Join remote node to kubernetes cluster

ip=$1
PASSWORD="rootroot"

ssh_expect() {
    command="$1"
    cat > /tmp/tmp.exp <<EOF
#!/usr/bin/expect
set password [lindex \$argv 0]
set cmd [lrange \$argv 1 end]

spawn {*}\$cmd

expect {
    "password" {
        send "\$password\r"
        exp_continue
    }
    "Are you sure you want to proceed?" {
        send "y\r"
        exp_continue
    }
    eof {
        exit
    }
}

interact
EOF

    expect /tmp/tmp.exp $PASSWORD $command
}

# Get token-ca-cert-hash
sha=$(openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | \
        openssl dgst -sha256 -hex | sed 's/^.* //')

# Get token of master node by creating new one
token=$(kubeadm token create)

# Join the remote node
cluster_ip=$(kubectl get node master -o jsonpath="{.status.addresses[0].address}")
ssh_expect "ssh root@$ip kubeadm reset"
ssh_expect "ssh root@$ip swapoff -a"
ssh_expect "ssh root@$ip kubeadm join ${cluster_ip}:6443 --token ${token} --discovery-token-ca-cert-hash sha256:${sha}"
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馃殌 Vagrant up and check result

  • UP
vagrant up
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  • Get nodes
vagrant@master:/vagrant$ kubectl get node
NAME     STATUS   ROLES                  AGE    VERSION
kube1    Ready    <none>                 2d1h   v1.21.0
kube2    Ready    <none>                 2d1h   v1.21.0
master   Ready    control-plane,master   2d1h   v1.21.0
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  • KVM

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Top comments (2)

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deepakkumarxftggn profile image
Deepak Kumar-xft

Hi Vu Dao, Thanks for sharing this vagrant file. Could you please share the git url to download this Vagrantfile. Please make sure, all commands should be in one file. Do I need to run different commands, as per your article above. Or just copy the first code in Vagrantfile and then run vagrant up? Please let me know.

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vumdao profile image
馃殌 Vu Dao 馃殌

Please check here github.com/vumdao/vagrant