#!/bin/bash
# Brett Kelly Oct 2021
# 45Drives
# Version 1.2 stable

usage() { # Help
cat << EOF
    Usage:	
        [-b] Block DB size. Required. Allowed suffixes K,M,G,T
        [-d] Device to use as db. Required. /dev/sdX
        [-f] Bypass osd per db warning
        [-o] OSDs to add db to. Required. Comma separated list of osd.id. <0,1,2,3>
        [-h] Displays this message
EOF
    exit 0
}

add_lv_tags(){
    get_lv_uuid(){
        local LV_UUID=$(lvs -o uuid $BLOCK_LV_DEVICE --no-headings | awk '{$1=$1};1')
        echo "$LV_UUID"
    }
    # Add block.db tags to existing block device
    lvchange --addtag "ceph.db_device=$DB_LV_DEVICE" $BLOCK_LV_DEVICE
    lvchange --addtag "ceph.db_uuid=$(get_lv_uuid $DB_LV_DEVICE)" $BLOCK_LV_DEVICE

    # Get all tags from existing block device and write them to new block.db
    # Both device should match except ceph.type=db and ceph.type=block

    BLOCK_LV_TAGS_STRING=$(lvs -o lv_tags --no-headings $BLOCK_LV_DEVICE | awk '{$1=$1};1')
    IFS=',' read -r -a BLOCK_LV_TAGS <<< "$BLOCK_LV_TAGS_STRING"
    for index in "${!BLOCK_LV_TAGS[@]}" ; do
        lvchange --addtag "${BLOCK_LV_TAGS[index]}" $DB_LV_DEVICE
    done
    lvchange --deltag "ceph.type=block" $DB_LV_DEVICE
    lvchange --addtag "ceph.type=db" $DB_LV_DEVICE
}

check_dependancies(){
    for i in "${!SCRIPT_DEPENDANCIES[@]}"; do
        if ! command -v ${SCRIPT_DEPENDANCIES[i]} >/dev/null 2>&1;then
	        echo "cli utility: ${SCRIPT_DEPENDANCIES[i]} is not installed"
            echo "jq, and bc are required"
	        exit 1
        fi
    done
}

# if encountering any error quit, so to not make a mess
set -e

SCRIPT_DEPENDANCIES=(bc jq)
FORCE="false"
PHYSICAL_EXTENT_SIZE_BYTES=4194304
OSD_PER_DB_LIMIT=5

while getopts 'b:fo:d:h' OPTION; do
    case ${OPTION} in
    b)
        BLOCK_DB_SIZE=${OPTARG}
        BLOCK_DB_SIZE_BYTES=$(numfmt --from=iec $BLOCK_DB_SIZE)
        ;;
    d)
        DB_DEVICE=${OPTARG}
        if [ ! -b $DB_DEVICE ];then
            echo "Error: DB_DEVICE=$DB_DEVICE is not a block device"
            exit 1
        fi
        ;;
    f)
        FORCE="true"
        ;;
    o)
        OSD_LIST_=${OPTARG}
        IFS=',' read -r -a OSD_LIST <<< "$OSD_LIST_"
        ;;
    h)
        usage
        ;;
    esac
done

# Check if correct input was given
if [ -z $OSD_LIST ] || [ -z $DB_DEVICE ] || [ -z $BLOCK_DB_SIZE_BYTES ]; then
    echo "Input required. See ./`basename "$0"` -h for usage details"
    exit 1
fi

# Check cli depandancies
check_dependancies

BLOCK_DB_SIZE_EXTENTS=$(bc <<< "$BLOCK_DB_SIZE_BYTES/$PHYSICAL_EXTENT_SIZE_BYTES")
OSD_COUNT="${#OSD_LIST[@]}"
TOTAL_DB_SIZE_BYTES=$(bc <<< "$BLOCK_DB_SIZE_BYTES*$OSD_COUNT")
DB_DEVICE_SIZE_BYTES=$(blockdev --getsize64 $DB_DEVICE)
DB_DEVICE_DISK_NAME=$(readlink -f $DB_DEVICE)

# Check if LVM info is already present on DB_DEVICE
LVM_JSON=$(pvs --units B --nosuffix -o name,vg_name,lv_name,lv_count,lvsize,vg_free --reportformat json )
LVM_JSON_DEVICE=$(echo $LVM_JSON | jq --arg disk "$DB_DEVICE_DISK_NAME" '.[] |.[].pv | .[] | select(.pv_name==$disk)')

# are we using an exitsing db device or a new device, if LVM_JSON is empty then assume new disk
if [ -z "$LVM_JSON_DEVICE" ];then
    DB_VG_NAME="ceph-$(uuidgen)"
else
    # if not how do we get db_VG ? inspect from device given
    DB_VG_NAME="$(echo $LVM_JSON_DEVICE | jq -r '.vg_name' | awk 'NR==1')"
    # Count how many lv dbs are present, add that to input osds and compare to OSD_LIMIT
    EXISTING_DB_COUNT=$(echo $LVM_JSON_DEVICE | jq -r '.lv_count' | awk 'NR==1')
    echo "WARNING: device currently has $EXISTING_DB_COUNT db's present"
    OSD_COUNT=$(bc <<< "${#OSD_LIST[@]}+$EXISTING_DB_COUNT")
    # set db total device size to the amount of free Bytes in the volume group
    DB_DEVICE_DISK_SIZE_BYTES=$(echo $LVM_JSON_DEVICE | jq -r '.vg_free' | awk 'NR==1')
fi

# Check if OSD_COUNT is greater than OSD_PER_DB_LIMIT, exit with warning. 
# If -f flag present the ignore OSD_PER_DB_LIMIT
if [ "$FORCE" == "false" ] ; then
    if [ "$OSD_COUNT" -gt "$OSD_PER_DB_LIMIT" ];then
        echo "Warning: OSD_COUNT is greater than OSD_PER_DB_LIMIT=$OSD_PER_DB_LIMIT. Use -f to bypass"
        exit 1
    fi
fi

# Check if total size of db's to be created will fit on db device
if [ "$TOTAL_DB_SIZE_BYTES" -gt "$DB_DEVICE_SIZE_BYTES" ] ; then
    echo "Warning: total size of db will not fit on device $DB_DEVICE"
    exit 1
fi

# Check each osd to see if it present on host
# Check each osd to see if it already has db device
# Check current bluestore db size and compare to chosen db size
# Gather ceph-volume output before entering loop as it takes a while to run
CEPH_VOLUME_JSON=$(ceph-volume lvm list --format json)
for i in "${!OSD_LIST[@]}"; do
    OSD_ID=${OSD_LIST[i]}
    OSD_JSON=$(echo $CEPH_VOLUME_JSON | jq -r --arg id "$OSD_ID" '.[] | .[] | select(.tags["ceph.osd_id"]==$id)')
    if [ -z "$OSD_JSON" ]; then
        echo "Can't find osd.$OSD_ID on this host"
        exit 1
    fi
    DB_CHECK=$(echo $OSD_JSON | jq 'select(.tags["ceph.db_device"])');
    if [ ! -z "$DB_CHECK" ]; then
        echo "Warning: osd.$OSD_ID already has a db device attached"
        exit 1
    fi
    CURRENT_BLOCK_DB_USED_BYTES=$(ceph daemon osd.$OSD_ID perf dump | jq '.bluefs | .db_used_bytes')
    if [[ "$CURRENT_BLOCK_DB_USED_BYTES" -ge "$BLOCK_DB_SIZE_BYTES" ]];then
        echo "Warning: osd.$OSD_ID has CURRENT_BLOCK_DB_USED_BYTES($(numfmt --to=iec $CURRENT_BLOCK_DB_USED_BYTES)). This must be less than BLOCK_DB_SIZE_BYTES($(numfmt --to=iec $BLOCK_DB_SIZE_BYTES))"
        exit 1
    fi
done

# Make sure ceph admin keyring is present hs correct permission
# Remove "set -e" so we can check ceph status error code
# Then turn it back on after
set +e
ceph status > /dev/null 2>&1 ; rc=$?
set -e
if [[ "$rc" -ne 0 ]];then
    echo "Warning: permisson denied accessing cluster, admin keyring must be present"
    exit 1
fi


CEPH_MAJOR_VERSION=$(ceph version | awk '{print $3}' | cut -d . -f 1)
if [ $CEPH_MAJOR_VERSION -gt "15" ];then
    echo "Warning: current process is not supported on clusters version 16 and up"
    exit 1
fi

# If we got this far then all checked are passed
# Start migration process

if [ -z "$LVM_JSON_DEVICE" ];then
    pvcreate $DB_DEVICE
    vgcreate $DB_VG_NAME $DB_DEVICE
fi

for i in "${!OSD_LIST[@]}"; do
    OSD_ID=${OSD_LIST[i]}
    OSD_JSON=$(echo $CEPH_VOLUME_JSON | jq -r --arg id "$OSD_ID" '.[] | .[] | select(.tags["ceph.osd_id"]==$id)')
    OSD_FSID=$(echo $OSD_JSON | jq -r '.tags["ceph.osd_fsid"]')

    DB_LV_UUID=$(uuidgen)
    DB_LV_DEVICE="/dev/$DB_VG_NAME/osd-db-$DB_LV_UUID"
    BLOCK_LV_DEVICE="$(echo $OSD_JSON | jq -r '.lv_path')"

    lvcreate -l $BLOCK_DB_SIZE_EXTENTS -n osd-db-$DB_LV_UUID $DB_VG_NAME

    chown -h ceph:ceph $DB_LV_DEVICE
    chown -R ceph:ceph $(realpath $DB_LV_DEVICE)

    # Call ceph health check function dont continue unless cluster healthy
    CEPH_STATUS=$(ceph health --format json | jq -r '.status')
    while [ "$CEPH_STATUS" != "HEALTH_OK" ]; do
        echo "Warning: Cluster is not in HEALTH_OK state"
        sleep 2
        CEPH_STATUS=$(ceph health --format json | jq -r '.status')
    done

    echo "Set noout"
    ceph osd set noout
    echo "Stop OSD.$OSD_ID"
    systemctl stop ceph-osd@$OSD_ID
    echo "Flush OSD Journal"
    ceph-osd -i $OSD_ID --flush-journal
    echo "Create new db"
    CEPH_ARGS="--bluestore-block-db-size $BLOCK_DB_SIZE_BYTES" ceph-bluestore-tool bluefs-bdev-new-db --path /var/lib/ceph/osd/ceph-$OSD_ID/ --dev-target $DB_LV_DEVICE
    echo "Migrate old db to new db"
    ceph-bluestore-tool bluefs-bdev-migrate --path /var/lib/ceph/osd/ceph-$OSD_ID/ --devs-source /var/lib/ceph/osd/ceph-$OSD_ID/block --dev-target /var/lib/ceph/osd/ceph-$OSD_ID/block.db
    echo "Update LV tags on block and db"
    add_lv_tags
    echo "unmount OSD.$OSD_ID"
    umount /var/lib/ceph/osd/ceph-$OSD_ID/
    echo "Activate OSD.$OSD_ID"
    ceph-volume lvm activate $OSD_ID $OSD_FSID
    echo "Unset noout"
    ceph osd unset noout
    echo "Verify osd is back up before continuing"
    OSD_STATE=$(ceph osd tree --format json | jq --arg id "$OSD_ID" -r '.nodes[] | select(.id == ($id |tonumber)) | .status')
    echo "OSD_STATE:  $OSD_STATE"
    while [ "$OSD_STATE" != "up" ]; do
        echo "Warning: OSD.$OSD_ID is not UP yet. Waiting..."
        sleep 2
        OSD_STATE=$(ceph osd tree --format json | jq --arg id "$OSD_ID" -r '.nodes[] | select(.id == ($id |tonumber)) | .status')
        echo "OSD_STATE:  $OSD_STATE"
    done
done