Setup script for google cloud instances with local disks

setup.sh

#!/usr/bin/env bash
set -euo pipefail

METADATA_BASE="http://metadata.google.internal/computeMetadata/v1/instance/attributes"

log() {
    local msg="${*}"
    logger -p syslog.info -t "startup-script" -- "${msg}"
}

fail() {
    local msg="${*}"
    logger -p syslog.error -t "startup-script" -- "${msg}"
    exit 1
}

run_or_die() {
    local argv=("${@}")
    log "run_or_die(${argv[*]})"
    "${argv[@]}"
}

metadata() {
    local key="${1}"
    curl --silent --connect-timeout 5 --fail \
        -H "Metadata-Flavor: Google" \
        "${METADATA_BASE}/${key}"
}

retry() {
    local argv=("${@}")
    until "${argv[@]}"; do
        log "'${argv[*]}' failed, retrying"
        sleep 1
    done
}

setup_apt() {
    retry apt update
    retry apt upgrade -y

    retry apt install -y \
        apt-transport-https ca-certificates curl \
        git gnupg lsb-release iftop mdadm xfsprogs
}

run_or_die setup_apt

setup_disks() {
    local mountdest=/data

    readarray -d '' local_disks < <(find /dev/disk/by-id -name "google-local-nvme-ssd-*" -print0)

    [[ ${#local_disks[@]} -eq 0 ]] && return

    local device=${local_disks[0]}

    if [[ ${#local_disks[@]} -gt 1 ]]; then
        mdadm --create /dev/md0 --level=0 --raid-devices="${#local_disks[@]}" "${local_disks[@]}"
        device=/dev/md0
    fi

    mkfs.xfs -f ${device}

    mkdir -p ${mountdest}
    mount ${device} ${mountdest}

    local mem_kb=$(cat /proc/meminfo | grep MemTotal | awk '{ print int($2 * 0.15) }')
    fallocate -l ${mem_kb}KiB ${mountdest}/swapfile
    chmod 600 ${mountdest}/swapfile
    mkswap ${mountdest}/swapfile
    swapon ${mountdest}/swapfile
}

run_or_die setup_disks