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EC2实例无法正确加载EBS卷大小问题的解决

EC2实例无法正确加载EBS卷大小问题的解决

EC2实例无法正确加载EBS卷大小问题的解决

问题描述

正常建立EC2实例的流程很简单。其中步骤4需要为实例添加存储:

2015082814352661

对于某些AMI(Amazon 系统映像)类型,创建好之后你会发现,本来为根目录指定了大小,还添加了新的存储卷,但是实例里面都没有正常显示。根目录一般只显示为5.7G大小。今天来说说如何让根目录显示正常(对于新建的存储卷,默认确实就是显示不出的,需要手动分区和挂载,这个以后再说)。

先说说正常创建的显示。比如创建EC2实例过程中,AMI选择默认的”快速启动”中的“Red Hat Enterprise Linux 7.1 (HVM),SSD 卷类型 – ami-9833a1a1”:

2015082814542284

并且将根目录设定为50G:

2015082815034492

实例创建好了之后登陆系统,你会看到正常的存储已经设置好:

2015082814563636

但如果AMI类型选择的是“社区AMI”中的“RHEL-6.4_HVM_GA-20141002-x86_64-11-Hourly2-GP2 – ami-7846d441”:

2015082815004564

同样设置根目录为50G。实例创建好之后,存储显示不正常:

2015082815530499

能够看到整个硬盘确实有50G,但只分给了根目录“/”5.7G,也就是说根目录并未得到我们分配的完整容量,磁盘空间设置有问题。

3 问题原因

究竟是什么原因导致这种情况的发生呢?这其实是由aws云的特性决定的。所谓眼见为实,不过现代社会中这句话要大打折扣,很多时候看到的结果都不是 想当然如此的。EC2作为AWS的虚拟产品,其所承载操作系统的构造和使用有许多不同于传统操作系统的地方。在早些时候,AWS的EC2实例创建之后都是需要手工扩展根卷的,只不过后来发展了根卷扩展脚本可以在EC2 launch的时候自动扩展,以帮助客户减轻负担。

明白了吧,也就是说你看到的“5.7G”其实是正常的结果,只不过还需要手工做些工作,完整的“50G”反而是有脚本在背后默默奉献才做到的,正是:

4 解决办法

现在明白了问题产生的原因了。有没有解决办法?当然有。其实就是说,整个根分区所在磁盘确实是有50G的,只是系统默认只给了根分区5.7G,我们需要做的就是修改根分区在分区表里起始和终止扇区的地址,使得根分区可以占据整个磁盘。AWS有手动扩展Linux分区的文档,可以参考。

有没有更简单一点的方式?答案还是有,那就是使用growpart工具(具体内容见本文最后的附录,MarkDown无法添加附件,只能全贴上来了。大家只需将其内容粘贴至一个文件,并将其命名为growpart即可)。growpart是AWS的扩展分区工具,只需简单几个命令就可以实现分区扩展,接下来讲一下使用方法。

4.1 准备growpart

登陆你的EC2实例,并将growpart脚本上传。

4.2 执行growpart

执行sh growpart -h,能够看到growpart的使用方法:

2015083118015740

能够看到growpart命令后面“/dev/sda”是设备文件名,“1”是分区号,注意EC2下操作要使用系统权限,即加上“sudo”:

2015090111203003

然后执行partprobe命令让内核重新读取分区表信息:

2015090111274761

4.3 重启系统

不过此时大多数情况下lsblk命令还是无法获取最新的磁盘信息,重启一下系统:

2015090111390843

4.4 查看扩展后分区信息

重启后重新登录,再次查看磁盘分区信息,能够看到扩展后根目录的分区覆盖了整个磁盘,为50G,达到了我们预期的效果:

2015090111503780

5 结束语

虽然问题结束了,但是小鱼还想啰嗦几句。从使用上来看,能看得出growpart这个工具还是很方便的,但是究竟哪些系统集成了growpart, 哪些系统没有集成而需要我们手动使用growpart扩展分区,这个AWS并没有给出明确的列表,大概比较新的镜像都对growpart做了集成,如 RedHead 7.1,还有AWS自己的Amazon Linux什么的。在这些系统下,能够看到growpart工具的脚本位置和所属安装包,如:

  • RedHead 7.1下这个脚本路径和所属安装包:
# which growpart
/bin/growpart

# rpm -qf /bin/growpart
cloud-utils-growpart-0.27-13.el7.noarch
  • Amazon Linux下这个脚本路径和所属安装包:
$ which growpart
/usr/bin/growpart

$ rpm -qf /usr/bin/growpart
cloud-disk-utils-0.27-1.4.amzn1.noarch
  • Ubuntu Linux下这个脚本路径和所属安装包:
# which growpart
/usr/bin/growpart

# dpkg -S /usr/bin/growpart
cloud-guest-utils: /usr/bin/growpart

在解决问题过程中得到了AWS的的不少帮助,在此表示感谢。不过,作为扩展分区这么重要的一个工具,growpart在AWS的文档中并没有被说明,脚本本身在AWS上 也没有链接,新手遇到问题只有盲人摸象了。这或许是EC2值得改进的一点吧。

6 附录(growpart脚本)

#!/bin/sh
#    Copyright (C) 2011 Canonical Ltd.
#    Copyright (C) 2013 Hewlett-Packard Development Company, L.P.
#
#    Authors: Scott Moser <smoser@canonical.com>
#             Juerg Haefliger <juerg.haefliger@hp.com>
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, version 3 of the License.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.

# the fudge factor. if its within this many 512 byte sectors, dont bother
FUDGE=${GROWPART_FUDGE:-$((20*1024))}
TEMP_D=""
RESTORE_FUNC=""
RESTORE_HUMAN=""
VERBOSITY=0
DISK=""
PART=""
PT_UPDATE=false
DRY_RUN=0

MBR_CHS=""
MBR_BACKUP=""
GPT_BACKUP=""
_capture=""

error() {
    echo "$@" 1>&2
}

fail() {
    [ $# -eq 0 ] || echo "FAILED:" "$@"
    exit 2
}

nochange() {
    echo "NOCHANGE:" "$@"
    exit 1
}

changed() {
    echo "CHANGED:" "$@"
    exit 0
}

change() {
    echo "CHANGE:" "$@"
    exit 0
}

cleanup() {
    if [ -n "${RESTORE_FUNC}" ]; then
        error "***** WARNING: Resize failed, attempting to revert ******"
        if ${RESTORE_FUNC} ; then
            error "***** Appears to have gone OK ****"
        else
            error "***** FAILED! or original partition table" \
                "looked like: ****"
            cat "${RESTORE_HUMAN}" 1>&2
        fi
    fi
    [ -z "${TEMP_D}" -o ! -d "${TEMP_D}" ] || rm -Rf "${TEMP_D}"
}

debug() {
    local level=${1}
    shift
    [ "${level}" -gt "${VERBOSITY}" ] && return
    if [ "${DEBUG_LOG}" ]; then
        echo "$@" >>"${DEBUG_LOG}"
    else
        error "$@"
    fi
}

debugcat() {
    local level="$1"
    shift;
    [ "${level}" -gt "$VERBOSITY" ] && return
    if [ "${DEBUG_LOG}" ]; then
        cat "$@" >>"${DEBUG_LOG}"
    else
        cat "$@" 1>&2
    fi
}

mktemp_d() {
    # just a mktemp -d that doens't need mktemp if its not there.
    _RET=$(mktemp -d "${TMPDIR:-/tmp}/${0##*/}.XXXXXX" 2>/dev/null) &&
        return
    _RET=$(umask 077 && t="${TMPDIR:-/tmp}/${0##*/}.$$" &&
        mkdir "${t}" &&	echo "${t}")
    return
}

Usage() {
    cat <<EOF
${0##*/} disk partition
   rewrite partition table so that partition takes up all the space it can
   options:
    -h | --help       print Usage and exit
         --fudge F    if part could be resized, but change would be
                      less than 'F', do not resize (default: ${FUDGE})
    -N | --dry-run    only report what would be done, show new 'sfdisk -d'
    -v | --verbose    increase verbosity / debug
    -u | --update  R  update the the kernel partition table info after growing
                      this requires kernel support and 'partx --update'
                      R is one of:
                       - 'auto'  : [default] update partition if possible
                       - 'force' : try despite sanity checks (fail on failure)
                       - 'off'   : do not attempt
                       - 'on'    : fail if sanity checks indicate no support

   Example:
    - ${0##*/} /dev/sda 1
      Resize partition 1 on /dev/sda
EOF
}

bad_Usage() {
    Usage 1>&2
    error "$@"
    exit 2
}

mbr_restore() {
    sfdisk --no-reread "${DISK}" ${MBR_CHS} -I "${MBR_BACKUP}"
}

sfdisk_worked_but_blkrrpart_failed() {
    local ret="$1" output="$2"
    # exit code found was just 1, but dont insist on that
    #[ $ret -eq 1 ] || return 1
    # Successfully wrote the new partition table
    grep -qi "Success.* wrote.* new.* partition" "$output" &&
        grep -qi "BLKRRPART: Device or resource busy" "$output"
    return
}

mbr_resize() {
    RESTORE_HUMAN="${TEMP_D}/recovery"
    MBR_BACKUP="${TEMP_D}/orig.save"

    local change_out=${TEMP_D}/change.out
    local dump_out=${TEMP_D}/dump.out
    local new_out=${TEMP_D}/new.out
    local dump_mod=${TEMP_D}/dump.mod
    local tmp="${TEMP_D}/tmp.out"
    local err="${TEMP_D}/err.out"

    local _devc cyl _w1 heads _w2 sectors _w3 tot dpart
    local pt_start pt_size pt_end max_end new_size change_info

    # --show-pt-geometry outputs something like
    #     /dev/sda: 164352 cylinders, 4 heads, 32 sectors/track
    rqe sfd_geom sfdisk "${DISK}" --show-pt-geometry >"${tmp}" &&
        read _devc cyl _w1 heads _w2 sectors _w3 <"${tmp}" &&
        MBR_CHS="-C ${cyl} -H ${heads} -S ${sectors}" ||
        fail "failed to get CHS from ${DISK}"

    tot=$((${cyl}*${heads}*${sectors}))

    debug 1 "geometry is ${MBR_CHS}. total size=${tot}"
    rqe sfd_dump sfdisk ${MBR_CHS} --unit=S --dump "${DISK}" \
        >"${dump_out}" ||
        fail "failed to dump sfdisk info for ${DISK}"

    {
        echo "## sfdisk ${MBR_CHS} --unit=S --dump ${DISK}"
        cat "${dump_out}"
    }  >"${RESTORE_HUMAN}"
    [ $? -eq 0 ] || fail "failed to save sfdisk -d output"

    debugcat 1 "${RESTORE_HUMAN}"

    sed -e 's/,//g; s/start=/start /; s/size=/size /' "${dump_out}" \
        >"${dump_mod}" ||
        fail "sed failed on dump output"

    dpart="${DISK}${PART}" # disk and partition number
    if [ -b "${DISK}p${PART}" -a "${DISK%[0-9]}" != "${DISK}" ]; then
        # for block devices that end in a number (/dev/nbd0)
        # the partition is "<name>p<partition_number>" (/dev/nbd0p1)
        dpart="${DISK}p${PART}"
    elif [ "${DISK#/dev/loop[0-9]}" != "${DISK}" ]; then
        # for /dev/loop devices, sfdisk output will be <name>p<number>
        # format also, even though there is not a device there.
        dpart="${DISK}p${PART}"
    fi

    pt_start=$(awk '$1 == pt { print $4 }' "pt=${dpart}" <"${dump_mod}") &&
        pt_size=$(awk '$1 == pt { print $6 }' "pt=${dpart}" <"${dump_mod}") &&
        [ -n "${pt_start}" -a -n "${pt_size}" ] &&
        pt_end=$((${pt_size}+${pt_start})) ||
        fail "failed to get start and end for ${dpart} in ${DISK}"

    # find the minimal starting location that is >= pt_end 
    max_end=$(awk '$3 == "start" { if($4 >= pt_end && $4 < min)
        { min = $4 } } END { printf("%s\n",min); }' \
        min=${tot} pt_end=${pt_end} "${dump_mod}") &&
        [ -n "${max_end}" ] ||
        fail "failed to get max_end for partition ${PART}"

    debug 1 "max_end=${max_end} tot=${tot} pt_end=${pt_end}" \
        "pt_start=${pt_start} pt_size=${pt_size}"
    [ $((${pt_end})) -eq ${max_end} ] &&
        nochange "partition ${PART} is size ${pt_size}. it cannot be grown"
    [ $((${pt_end}+${FUDGE})) -gt ${max_end} ] &&
        nochange "partition ${PART} could only be grown by" \
        "$((${max_end}-${pt_end})) [fudge=${FUDGE}]"

    # now, change the size for this partition in ${dump_out} to be the
    # new size
    new_size=$((${max_end}-${pt_start}))
    sed "\|^\s*${dpart} |s/${pt_size},/${new_size},/" "${dump_out}" \
        >"${new_out}" ||
        fail "failed to change size in output"

    change_info="partition=${PART} start=${pt_start} old: size=${pt_size} end=${pt_end} new: size=${new_size},end=${max_end}"
    if [ ${DRY_RUN} -ne 0 ]; then
        echo "CHANGE: ${change_info}"
        {
            echo "# === old sfdisk -d ==="
            cat "${dump_out}"
            echo "# === new sfdisk -d ==="
            cat "${new_out}"
        } 1>&2
        exit 0
    fi

    LANG=C sfdisk --no-reread "${DISK}" ${MBR_CHS} --force \
        -O "${MBR_BACKUP}" <"${new_out}" >"${change_out}" 2>&1
    ret=$?
    [ $ret -eq 0 ] || RESTORE_FUNC="mbr_restore"

    if [ $ret -eq 0 ]; then
        :
    elif $PT_UPDATE &&
        sfdisk_worked_but_blkrrpart_failed "$ret" "${change_out}"; then
        # if the command failed, but it looks like only because
        # the device was busy and we have pt_update, then go on
        debug 1 "sfdisk failed, but likely only because of blkrrpart"
    else
        error "attempt to resize ${DISK} failed. sfdisk output below:"
        sed 's,^,| ,' "${change_out}" 1>&2
        fail "failed to resize"
    fi

    rq pt_update pt_update "$DISK" "$PART" ||
        fail "pt_resize failed"

    RESTORE_FUNC=""

    changed "${change_info}"

    # dump_out looks something like:
    ## partition table of /tmp/out.img
    #unit: sectors
    #
    #/tmp/out.img1 : start=        1, size=    48194, Id=83
    #/tmp/out.img2 : start=    48195, size=   963900, Id=83
    #/tmp/out.img3 : start=  1012095, size=   305235, Id=82
    #/tmp/out.img4 : start=  1317330, size=   771120, Id= 5
    #/tmp/out.img5 : start=  1317331, size=   642599, Id=83
    #/tmp/out.img6 : start=  1959931, size=    48194, Id=83
    #/tmp/out.img7 : start=  2008126, size=    80324, Id=83
}

gpt_restore() {
    sgdisk -l "${GPT_BACKUP}" "${DISK}"
}

gpt_resize() {
    GPT_BACKUP="${TEMP_D}/pt.backup"

    local pt_info="${TEMP_D}/pt.info"
    local pt_pretend="${TEMP_D}/pt.pretend"
    local pt_data="${TEMP_D}/pt.data"
    local out="${TEMP_D}/out"

    local dev="disk=${DISK} partition=${PART}"

    local pt_start pt_end pt_size last pt_max code guid name new_size
    local old new change_info

    # Dump the original partition information and details to disk. This is
    # used in case something goes wrong and human interaction is required
    # to revert any changes.
    rqe sgd_info sgdisk "--info=${PART}" --print "${DISK}" >"${pt_info}" ||
    RESTORE_HUMAN="${pt_info}"

    debug 1 "$dev: original sgdisk info:"
    debugcat 1 "${pt_info}"

    # Pretend to move the backup GPT header to the end of the disk and dump
    # the resulting partition information. We use this info to determine if
    # we have to resize the partition.
    rqe sgd_pretend sgdisk --pretend --move-second-header \
        --print "${DISK}" >"${pt_pretend}" ||
        fail "${dev}: failed to dump pretend sgdisk info"

    debug 1 "$dev: pretend sgdisk info"
    debugcat 1 "${pt_pretend}"

    # Extract the partition data from the pretend dump
    awk 'found { print } ; $1 == "Number" { found = 1 }' \
        "${pt_pretend}" >"${pt_data}" ||
        fail "${dev}: failed to parse pretend sgdisk info"

    # Get the start and end sectors of the partition to be grown
    pt_start=$(awk '$1 == '"${PART}"' { print $2 }' "${pt_data}") &&
        [ -n "${pt_start}" ] ||
        fail "${dev}: failed to get start sector"
    pt_end=$(awk '$1 == '"${PART}"' { print $3 }' "${pt_data}") &&
        [ -n "${pt_end}" ] ||
        fail "${dev}: failed to get end sector"
    pt_size="$((${pt_end} - ${pt_start}))"

    # Get the last usable sector
    last=$(awk '/last usable sector is/ { print $NF }' \
        "${pt_pretend}") && [ -n "${last}" ] ||
        fail "${dev}: failed to get last usable sector"

    # Find the minimal start sector that is >= pt_end 
    pt_max=$(awk '{ if ($2 >= pt_end && $2 < min) { min = $2 } } END \
        { print min }' min="${last}" pt_end="${pt_end}" \
        "${pt_data}") && [ -n "${pt_max}" ] ||
        fail "${dev}: failed to find max end sector"

    debug 1 "${dev}: pt_start=${pt_start} pt_end=${pt_end}" \
        "pt_size=${pt_size} pt_max=${pt_max} last=${last}"

    # Check if the partition can be grown
    [ "${pt_end}" -eq "${pt_max}" ] &&
        nochange "${dev}: size=${pt_size}, it cannot be grown"
    [ "$((${pt_end} + ${FUDGE}))" -gt "${pt_max}" ] &&
        nochange "${dev}: could only be grown by" \
        "$((${pt_max} - ${pt_end})) [fudge=${FUDGE}]"

    # The partition can be grown if we made it here. Get some more info
    # about it so we can do it properly.
    # FIXME: Do we care about the attribute flags?
    code=$(awk '/^Partition GUID code:/ { print $4 }' "${pt_info}")
    guid=$(awk '/^Partition unique GUID:/ { print $4 }' "${pt_info}")
    name=$(awk '/^Partition name:/ { gsub(/'"'"'/, "") ; \
        if (NF >= 3) print substr($0, index($0, $3)) }' "${pt_info}")
    [ -n "${code}" -a -n "${guid}" ] ||
        fail "${dev}: failed to parse sgdisk details"

    debug 1 "${dev}: code=${code} guid=${guid} name='${name}'"

    # Calculate the new size of the partition
    new_size=$((${pt_max} - ${pt_start}))
    old="old: size=${pt_size},end=${pt_end}"
    new="new: size=${new_size},end=${pt_max}"
    change_info="${dev}: start=${pt_start} ${old} ${new}"

    # Dry run
    [ "${DRY_RUN}" -ne 0 ] && change "${change_info}"

    # Backup the current partition table, we're about to modify it
    rq sgd_backup sgdisk "--backup=${GPT_BACKUP}" "${DISK}" ||
        fail "${dev}: failed to backup the partition table"

    # Modify the partition table. We do it all in one go (the order is
    # important!):
    #  - move the GPT backup header to the end of the disk
    #  - delete the partition
    #  - recreate the partition with the new size
    #  - set the partition code
    #  - set the partition GUID
    #  - set the partition name
    rq sgdisk_mod sgdisk --move-second-header "--delete=${PART}" \
        "--new=${PART}:${pt_start}:${pt_max}" \
        "--typecode=${PART}:${code}" \
        "--partition-guid=${PART}:${guid}" \
        "--change-name=${PART}:${name}" "${DISK}" &&
        rq pt_update pt_update "$DISK" "$PART" || {
        RESTORE_FUNC=gpt_restore
        fail "${dev}: failed to repartition"
    }

    changed "${change_info}"
}

kver_to_num() {
    local kver="$1" maj="" min="" mic="0"
    kver=${kver%%-*}
    maj=${kver%%.*}
    min=${kver#${maj}.}
    min=${min%%.*}
    mic=${kver#${maj}.${min}.}
    [ "$kver" = "$mic" ] && mic=0
    _RET=$(($maj*1000*1000+$min*1000+$mic))
}

kver_cmp() {
    local op="$2" n1="" n2=""
    kver_to_num "$1"
    n1="$_RET"
    kver_to_num "$3"
    n2="$_RET"
    [ $n1 $op $n2 ]
}

rq() {
    # runquieterror(label, command)
    # gobble stderr of a command unless it errors
    local label="$1" ret="" efile=""
    efile="$TEMP_D/$label.err"
    shift;
    debug 2 "running[$label][$_capture]" "$@"
    if [ "${_capture}" = "erronly" ]; then
        "$@" 2>"$TEMP_D/$label.err"
        ret=$?
    else
        "$@" >"$TEMP_D/$label.err" 2>&1
        ret=$?
    fi
    if [ $ret -ne 0 ]; then
        error "failed [$label:$ret]" "$@"
        cat "$efile" 1>&2
    fi
    return $ret
}

rqe() {
    local _capture="erronly"
    rq "$@"
}

verify_ptupdate() {
    local input="$1" found="" reason="" kver=""

    # we can always satisfy 'off'
    if [ "$input" = "off" ]; then
        _RET="false";
        return 0;
    fi

    if command -v partx >/dev/null 2>&1; then
        partx --help 2>/dev/null | grep -q -- --update || {
            reason="partx has no '--update' flag in usage."
            found="off"
        }
    else
        reason="no 'partx' command"
        found="off"
    fi

    if [ -z "$found" ]; then
        if [ "$(uname)" != "Linux" ]; then
            reason="Kernel is not Linux per uname."
            found="off"
        fi
    fi

    if [ -z "$found" ]; then
        kver=$(uname -r) || debug 1 "uname -r failed!"

        if ! kver_cmp "${kver-0.0.0}" -ge 3.8.0; then
            reason="Kernel '$kver' < 3.8.0."
            found="off"
        fi
    fi

    if [ -z "$found" ]; then
        _RET="true"
        return 0
    fi

    case "$input" in
        on) error "$reason"; return 1;;
        auto)
            _RET="false";
            debug 1 "partition update disabled: $reason"
            return 0;;
        force)
            _RET="true"
            error "WARNING: ptupdate forced on even though: $reason"
            return 0;;
    esac
    error "unknown input '$input'";
    return 1;
}

pt_update() {
    local dev="$1" part="$2" update="${3:-$PT_UPDATE}"
    if ! $update; then
        return 0
    fi
    partx --update "$part" "$dev"
}

has_cmd() {
    command -v "${1}" >/dev/null 2>&1
}

pt_update="auto"
while [ $# -ne 0 ]; do
    cur=${1}
    next=${2}
    case "$cur" in
        -h|--help)
            Usage
            exit 0
            ;;
        --fudge)
            FUDGE=${next}
            shift
            ;;
        -N|--dry-run)
            DRY_RUN=1
            ;;
        -u|--update|--update=*)
            if [ "${cur#--update=}" != "$cur" ]; then
                next="${cur#--update=}"
            else
                shift
            fi
            case "$next" in
                off|auto|force|on) pt_update=$next;;
                *) fail "unknown --update option: $next";;
            esac
            ;;
        -v|--verbose)
            VERBOSITY=$(($VERBOSITY+1))
            ;;
        --)
            shift
            break
            ;;
        -*)
            fail "unknown option ${cur}"
            ;;
        *)
            if [ -z "${DISK}" ]; then
                DISK=${cur}
            else
                [ -z "${PART}" ] || fail "confused by arg ${cur}"
                PART=${cur}
            fi
            ;;
    esac
    shift
done

[ -n "${DISK}" ] || bad_Usage "must supply disk and partition-number"
[ -n "${PART}" ] || bad_Usage "must supply partition-number"

has_cmd "sfdisk" || fail "sfdisk not found"

[ -e "${DISK}" ] || fail "${DISK}: does not exist"

[ "${PART#*[!0-9]}" = "${PART}" ] || fail "partition-number must be a number"

verify_ptupdate "$pt_update" || fail
PT_UPDATE=$_RET

debug 1 "update-partition set to $PT_UPDATE"

mktemp_d && TEMP_D="${_RET}" || fail "failed to make temp dir"
trap cleanup EXIT

# get the ID of the first partition to determine if it's MBR or GPT
id=$(sfdisk --id --force "${DISK}" 1 2>/dev/null) ||
    fail "unable to determine partition type"

if [ "${id}" = "ee" ] ; then
    has_cmd "sgdisk" || fail "GPT partition found but no sgdisk"
    debug 1 "found GPT partition table (id = ${id})"
    gpt_resize
else
    debug 1 "found MBR partition table (id = ${id})"
    mbr_resize
fi

# vi: ts=4 noexpandtab