Preparing for installing kubeadm.

kubeadm-prerequisites.sh

#!/bin/bash
set -e

CNI_VERSION="v1.3.0"
ARCH="amd64"
CRICTL_VERSION="v1.27.1"

setup_color() {
    # Only use colors if connected to a terminal
    if ! is_tty; then
        FMT_RAINBOW=""
        FMT_RED=""
        FMT_GREEN=""
        FMT_YELLOW=""
        FMT_BLUE=""
        FMT_BOLD=""
        FMT_RESET=""
        return
    fi

    if supports_truecolor; then
        FMT_RAINBOW="
        $(printf '\033[38;2;255;0;0m')
        $(printf '\033[38;2;255;97;0m')
        $(printf '\033[38;2;247;255;0m')
        $(printf '\033[38;2;0;255;30m')
        $(printf '\033[38;2;77;0;255m')
        $(printf '\033[38;2;168;0;255m')
        $(printf '\033[38;2;245;0;172m')
        "
    else
        FMT_RAINBOW="
        $(printf '\033[38;5;196m')
        $(printf '\033[38;5;202m')
        $(printf '\033[38;5;226m')
        $(printf '\033[38;5;082m')
        $(printf '\033[38;5;021m')
        $(printf '\033[38;5;093m')
        $(printf '\033[38;5;163m')
        "
    fi

    FMT_RED=$(printf '\033[31m')
    FMT_GREEN=$(printf '\033[32m')
    FMT_YELLOW=$(printf '\033[33m')
    FMT_BLUE=$(printf '\033[34m')
    FMT_BOLD=$(printf '\033[1m')
    FMT_RESET=$(printf '\033[0m')
}

install_container_runtime() {
    echo "${FMT_GREEN}Installing containerd...${FMT_RESET}"
    sudo yum install -y yum-utils device-mapper-persistent-data lvm2
    sudo yum-config-manager \
        --add-repo \
        https://download.docker.com/linux/centos/docker-ce.repo
    sudo yum install containerd.io -y

    # Configure containerd
    sudo mkdir -p /etc/containerd
    sudo containerd config default > /etc/containerd/config.toml
    # Use systemd as cgroup driver
    sed -i 's/SystemdCgroup = false/SystemdCgroup = true/g' /etc/containerd/config.toml
    sudo systemctl is-active --quiet containerd || sudo systemctl start containerd
    sudo systemctl is-enabled --quiet containerd || sudo systemctl enable containerd
}

install_dep() {
    # socat
    echo "${FMT_GREEN}Installing socat...${FMT_RESET}"
    sudo yum install -y socat

    # tc
    echo "${FMT_GREEN}Installing tc...${FMT_RESET}"
    sudo yum install -y iproute-tc

    # conntrack
    echo "${FMT_GREEN}Installing conntrack...${FMT_RESET}"
    sudo yum install -y conntrack

    # CNI plugins
    echo "${FMT_GREEN}Installing CNI plugins...${FMT_RESET}"
    sudo mkdir -p /opt/cni/bin
    sudo curl -L "https://github.com/containernetworking/plugins/releases/download/${CNI_VERSION}/cni-plugins-linux-${ARCH}-${CNI_VERSION}.tgz" | sudo tar -C /opt/cni/bin -xz

    DOWNLOAD_DIR=/usr/local/bin
    sudo mkdir -p $DOWNLOAD_DIR
    echo "${FMT_GREEN}Installing crictl...${FMT_RESET}"
    # crictl
    curl -L "https://github.com/kubernetes-sigs/cri-tools/releases/download/${CRICTL_VERSION}/crictl-${CRICTL_VERSION}-linux-${ARCH}.tar.gz" | sudo tar -C $DOWNLOAD_DIR -xz

    # kubeadm kubelet kubectl
    RELEASE=$1
    if [ -z $RELEASE ]; then
        RELEASE="$(curl -sSL https://dl.k8s.io/release/stable.txt)"
    fi
    echo "${FMT_GREEN}Installing kubeadm, kubelet and kubectl...${FMT_RESET}"
    pushd $DOWNLOAD_DIR
    sudo curl -L --remote-name-all https://storage.googleapis.com/kubernetes-release/release/${RELEASE}/bin/linux/${ARCH}/{kubeadm,kubelet,kubectl}
    sudo chmod +x {kubeadm,kubelet,kubectl}
    popd

    RELEASE_VERSION="v0.4.0"
    curl -sSL "https://raw.githubusercontent.com/kubernetes/release/${RELEASE_VERSION}/cmd/kubepkg/templates/latest/deb/kubelet/lib/systemd/system/kubelet.service" | sed "s:/usr/bin:${DOWNLOAD_DIR}:g" | sudo tee /etc/systemd/system/kubelet.service
    sudo mkdir -p /etc/systemd/system/kubelet.service.d
    curl -sSL "https://raw.githubusercontent.com/kubernetes/release/${RELEASE_VERSION}/cmd/kubepkg/templates/latest/deb/kubeadm/10-kubeadm.conf" | sed "s:/usr/bin:${DOWNLOAD_DIR}:g" | sudo tee /etc/systemd/system/kubelet.service.d/10-kubeadm.conf

    sudo systemctl is-enabled --quiet kubelet || sudo systemctl enable kubelet
}


os_config() {
    # Disable SELinux
    if [ "$(getenforce)" != "Disabled" ]; then
        echo "${FMT_GREEN}Disabling SELinux...${FMT_RESET}"
        sudo setenforce 0
        sed -i "s/^SELINUX=.*$/SELINUX=disabled/g" /etc/selinux/config
    fi
    # Disable swap
    if [ $(cat /proc/swaps | wc -l) -eq 2 ]; then
        echo "${FMT_GREEN}Disabling swap...${FMT_RESET}"
        sudo swapoff -a
        sed -i "/ swap / s/^/#/" /etc/fstab
    fi
}

br_netfilter() {
    cat <<EOF | sudo tee /etc/modules-load.d/containerd.conf
overlay
br_netfilter
EOF

    sudo modprobe overlay
    sudo modprobe br_netfilter

    # Setup required sysctl params, these persist across reboots.
    cat <<EOF | sudo tee /etc/sysctl.d/99-kubernetes-cri.conf
net.bridge.bridge-nf-call-iptables  = 1
net.ipv4.ip_forward                 = 1
net.bridge.bridge-nf-call-ip6tables = 1
EOF

    sudo sysctl --system
}

main() {
    setup_color

    if [[ $(systemctl cat firewalld.service > /dev/null 2>&1) -eq 0 ]]; then
        sudo systemctl is-active --quiet firewalld && sudo systemctl stop firewalld
        sudo systemctl is-enabled --quiet firewalld && sudo systemctl disable firewalld
    fi
    if [[ $(uname -p) == "aarch64" ]]; then
        ARCH="aarch64"
    fi
    sudo yum update -y
    br_netfilter
    install_container_runtime
    install_dep $1
    os_config
}

main "$@"

sh -c "$(curl -fssL https://gist.githubusercontent.com/crazytaxii/802a5dc93d6a0cc2cb606709b2ac0d16/raw/40febedde7c6f2a5d1e183f5ce08171524b5e747/kubeadm-prerequisites.sh)"