aws-ec2-ephemeral-mdadm.sh

#!/usr/bin/env bash
#===============================================================================
#   DESCRIPTION: aws-ec2-ephemeral-mdadm.sh
#        AUTHOR: Aleksandr Kukhar (kyxap), kyxap@kyxap.pro
#       COMPANY: Fasten.com
#  ORGANIZATION: Operations
#       CREATED: 03/17/17 02:13 +0000 UTC
#===============================================================================
set -o pipefail
set -eu

# temporary disable
#trap "{ echo -n [\$\$] \${BASH_COMMAND[*]}; [[ \$? -eq 2 ]] || usage; }" INT TERM EXIT

usage_='^(help|usage)$'
function usage {
cat <<EOF
        Script to create mdadm stripe in AWS EC2 environment
USAGE:  REQUIRED [OPTIONAL] $0
REQUIRED
        DEVICES           devices list          DEVICES="/dev/xvdf /dev/xvdg"
        MOUNTPOINT        mountpoint            MOUNTPOINT=/var/lib/cassandra
        LABEL             filesystem label      LABEL=CASSANDRA
OPTIONAL
        MOUNTOPTS         mount options         MOUNTOPTS="nobootwait,nofail"
        CONF              mdadm configm         CONF=/etc/mdadm/mdadm.conf
        MD                md device             MD=/dev/md127
        FS                filesystem type       FS=xfs || ext4
        RAID              raid category         RAID=ebs || ephemeral | noraid
SAMPLE
DEVICES=\$(echo /dev/xvd{f..i}) MOUNTPOINT=/var/lib/cassandra\
 MOUNTOPTS="nobootwait,nofail" CONF=/etc/mdadm/mdadm.conf LABEL=CASSANDRA\
 MD=/dev/md127 FS=xfs RAID=ebs\
 $0
EOF
exit 2
}

DEVICES=(${DEVICES[@]:?})
MOUNTPOINT="${MOUNTPOINT:?}"
MOUNTOPTS="${MOUNTOPTS:-nobootwait,nofail}"
CONF="${CONF:-/etc/mdadm/mdadm.conf}"
LABEL="${LABEL:?}"
MD="${MD:-/dev/md0}"
FS="${FS:-xfs}"
RAID="${RAID:-ebs}"

function prepareenv  { mkdir -p "${CONF%/*}"; mkdir -p "${MOUNTPOINT}"; }
function createconf  { echo "DEVICE ${DEVICES[@]}" | tee -a ${CONF}; mdadm --detail --scan | tee -a ${CONF}; }
function createfs    { mkfs.${FS} -L ${LABEL} -f ${MD}; }
function mountfs     { mountpoint -q ${MOUNTPOINT} || mount ${MD} ${MOUNTPOINT}; }
function umountfs    { mountpoint -q ${MOUNTPOINT} || return 0 && umount ${MOUNTPOINT}; }
function createmd    { echo y | mdadm --create ${MD} --level=0 --raid-devices=${#DEVICES[@]} ${DEVICES[@]}; }
function exammd      { mdadm --examine ${DEVICES[@]}; }
function stopmd      { mdadm --stop ${MD}; }
function removemd    { mdadm --remove ${MD}; }
function destroymd   { mdadm --zero-superblock ${DEVICES[@]}; }
function destroyconf { [[ -s ${CONF} ]] || return 0 && rm -rf "${CONF%/*}"; }
function lookupdev   { printf "%s\n" "${DEVICES[@]##*/}" | grep -cwof - /proc/partitions; }
function statusdev   { [[ -s ${CONF} ]] && { [[ -b ${MD} ]] || return 0; }; exammd; }
function validatedev { if n=$( lookupdev ); then [[ ${n} -eq ${#DEVICES[@]} ]] || exit 1; fi; }
function addfstab    { echo "LABEL=${LABEL} ${MOUNTPOINT} auto ${MOUNTOPTS} 0 0" | tee -a /etc/fstab >/dev/null; }
function delfstab    { grep -v "LABEL=${LABEL} ${MOUNTPOINT} auto ${MOUNTOPTS} 0 0" /etc/fstab > /tmp/fstab; mv -f /tmp/fstab /etc/fstab; }
function createlabel { [[ ${FS} == ext[234] ]] && tune2fs -L ${LABEL} ${MD}; [[ ${FS} == xfs ]] && xfs_admin -L ${LABEL} ${MD}; }
function finish      { exit 0; }

CMD=${@:-create}
[[ ${RAID} == noraid    ]] && { validatedev; prepareenv; createlabel; addfstab; mountfs && finish || finish; }
[[ ${CMD}  == status    ]] && { statusdev && finish; }
[[ ${CMD}  == create    ]] && { validatedev; prepareenv; createmd; createfs; createlabel; createconf; addfstab; mountfs && finish; }
[[ ${CMD}  == destroy   ]] && { umountfs; delfstab; destroyconf; stopmd; destroymd && finish; }
[[ ${CMD}  =~ ${usage_} ]] && { usage && finish; }

exit 0