#!/bin/bash
# script that runs 
# https://kubernetes.io/docs/setup/production-environment/container-runtime

# changes March 14 2023: introduced $PLATFORM to have this work on amd64 as well as arm64

# setting MYOS variable
MYOS=$(hostnamectl | awk '/Operating/ { print $3 }')
OSVERSION=$(hostnamectl | awk '/Operating/ { print $4 }')
# beta: building in ARM support
[ $(arch) = aarch64 ] && PLATFORM=arm64
[ $(arch) = x86_64 ] && PLATFORM=amd64

if [ $MYOS = "Ubuntu" ]
then
	### setting up container runtime prereq
	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

        # Apply sysctl params without reboot
        sudo sysctl --system

        # (Install containerd)

        #sudo apt-get update && sudo apt-get install -y containerd
        # hopefully temporary bugfix as the containerd version provided in Ubu repo is tool old
        # added Jan 26th 2023
        # this needs to be updated when a recent enough containerd version will be in Ubuntu repos
         sudo systemctl stop containerd
         cleanup old files from previous attempt if existing
        [ -d bin ] && rm -rf bin
        wget https://github.com/containerd/containerd/releases/download/v1.7.13/containerd-1.7.13-linux-${PLATFORM}.tar.gz
        tar xvf containerd-1.7.13-linux-${PLATFORM}.tar.gz
        sudo mv bin/* /usr/bin/
        # Configure containerd
        sudo mkdir -p /etc/containerd
        cat <<- TOML | sudo tee /etc/containerd/config.toml
version = 2
[plugins]
  [plugins."io.containerd.grpc.v1.cri"]
    [plugins."io.containerd.grpc.v1.cri".containerd]
      discard_unpacked_layers = true
      [plugins."io.containerd.grpc.v1.cri".containerd.runtimes]
        [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc]
          runtime_type = "io.containerd.runc.v2"
          [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options]
            SystemdCgroup = true
        TOML

        # Restart containerd
        wget https://raw.githubusercontent.com/containerd/containerd/main/containerd.service
        sudo mv containerd.service /usr/lib/systemd/system/
        sudo systemctl daemon-reload
        sudo systemctl enable --now containerd
fi

exit
#### notes from history just in case

 wget https://github.com/opencontainers/runc/releases/download/v1.1.12/runc.amd64
   install -m 755 runc.amd64 /usr/local/sbin/runc