#!/bin/bash

if [ ${DIB_DEBUG_TRACE:-0} -gt 0 ]; then
    set -x
fi
set -eu
set -o pipefail

# Upgrade CentOS to 7.2
sudo -E yum upgrade --assumeyes --tolerant
sudo -E yum update --assumeyes

# Verify that the kernel is at least 3.10
function version_gt() { test "$(echo "$@" | tr " " "\n" | sort -V | head -n 1)" != "$1"; }

kernel_version=`uname -r | cut --bytes=1-4`
expect_version=3.10
if version_gt $expect_version $kernel_version; then
    echo "Error: kernel version at least $expect_version, current version $kernel_version"
    exit 1
fi

# Enable OverlayFS
sudo tee /etc/modules-load.d/overlay.conf <<-'EOF'
overlay
EOF