check_zpool

#!/bin/bash

PROGNAME=${0##*/}

function nagios_exit_usage() {
    echo "\
Usage: $PROGNAME [OPTION...]
Nagios plugin to check zpools status and usage

Common options:
  -w, --warning-usage   INT     Percent usage warning threshold
  -c, --critical-usage  INT     Percent usage critical threshold
  -S, --sudo-user       USER    Run commands with sudo -u USER
  -h, --help                    Display this help

SSH options:
  -s, --ssh           CMD     Custom SSH command, see documentation below
  -H, --host          HOST    SSH host
  -p, --port          INT     SSH port
  -u, --ssh-user      USER    SSH username
  -i, --ssh-identity  FILE    SSH identity key file
  -t, --timeout       INT     SSH connect timeout

SNMP options:
  -H, --host          HOST    SNMP host
  -p, --port          INT     SNMP port
  -t, --timeout       INT     Alias for SNMP option -t (timeout)
  -O, --snmp-oid      OID     OID that return result in get_zpool format
  -P, --snmp-options  ARGS    SNMP options, eg: -v 2c -c public, end with --

When using option -s, --ssh, classic SSH options get ignored. It is then
up to the caller to properly escape args and handle SSH options like
identity, port, user, connect timeout.
Usage example: $PROGNAME -s 'ssh -i key cmd@bastion host' ...

When using option -O, --snmp-oid, commands output is retrieved from
the given OID.

Sample snmpd extend configuration (note the extend command is split in two
line here for formatting purpose, stick to one line in snmpd configuration):
# NET-SNMP-EXTEND-MIB::nsExtendOutputFull.\"zpool\"
# .1.3.6.1.4.1.8072.1.3.2.3.1.2.5.122.112.111.111.108
extend zpool /bin/sh -c '/usr/sbin/zpool list -o name,health; \\
    /usr/sbin/zfs list -d 0 -p -o name,used,avail'
"
    exit 3
}

function nagopt_var() {
    [[ -z $2 || $2 == '$' ]] && return
    declare -g "$1=$2"
}

function nagopt_arglist() {
    local var=$1; shift
    local value=()
    while (( $# > 0 )) && [[ $1 != -- ]]; do
        value+=( "$1" )
        shift
    done
    declare -ga "$var=( \"\${value[@]}\" )"
}

function get_zpool() {
    if [[ -n $SNMP_OID && -n $HOST ]]; then
        snmpget -OqevU "${SNMP_OPTIONS[@]}" ${TIMEOUT:+-t "$TIMEOUT"} \
            "${HOST}${PORT:+:$PORT}" "$SNMP_OID" |
                tr -d '"' |grep -Fv 'No Such Instance' || return 2
    else
        local cmd1=( ${SUDO_USER:+sudo -n -u "$SUDO_USER"} zpool list -o name,health )
        local cmd2=( ${SUDO_USER:+sudo -n -u "$SUDO_USER"} zfs list -d 0 -p -o name,used,avail )
        if [[ -n $SSH_CMD ]]; then
            # custom ssh command: it is up to the caller to properly escape args
            # and handle ssh options like identity, port, user, connect timeout
            $SSH_CMD -- "${cmd1[@]@Q} ; ${cmd2[@]@Q}"
        elif [[ -n $HOST ]]; then
            ssh ${SSH_IDENTITY:+-i "$SSH_IDENTITY"} ${SSH_USER:+-l "$SSH_USER"} \
                ${PORT:+-p "$PORT"} -q -C -T -o StrictHostKeyChecking=no \
                -o UserKnownHostsFile=/dev/null -o PreferredAuthentications=publickey \
                ${TIMEOUT:+-o "ConnectTimeout=$TIMEOUT"} "$HOST" -- "${cmd1[@]@Q} ; ${cmd2[@]@Q}"
        else
            "${cmd1[@]}"; "${cmd2[@]}"
        fi
    fi
}

HOST=
PORT=
SSH_USER=
SSH_IDENTITY=
TIMEOUT=
SUDO_USER=
SNMP_OID=
SNMP_OPTIONS=()
WARNING_USAGE=
CRITICAL_USAGE=

while (( $# > 0 )); do
    case "$1" in
        # ssh, snmp
        -H|--host) nagopt_var HOST "$2"; shift ;;
        -p|--port) nagopt_var PORT "$2"; shift ;;
        -t|--timeout) nagopt_var TIMEOUT "$2"; shift ;;
        # ssh
        -s|--ssh) nagopt_var SSH_CMD "$2"; shift ;;
        -u|--ssh-user) nagopt_var SSH_USER "$2"; shift ;;
        -i|--ssh-identity) nagopt_var SSH_IDENTITY "$2"; shift ;;
        # snmp
        -O|--snmp-oid) nagopt_var SNMP_OID "$2"; shift ;;
        -P|--snmp-options) nagopt_arglist SNMP_OPTIONS "${@:2}"; shift $((${#SNMP_OPTIONS[@]}+1)) ;;
        # common
        -w|--warning-usage) nagopt_var WARNING_USAGE "$2"; shift ;;
        -c|--critical-usage) nagopt_var CRITICAL_USAGE "$2"; shift ;;
        -S|--sudo-user) nagopt_var SUDO_USER "$2"; shift ;;
        -h|--help) nagios_exit_usage ;;
        *) nagios_exit_usage ;;
    esac
    shift
done

REPLY=$(get_zpool)
ret=$?

if [[ ( -n $SSH_CMD || (-n $HOST && -z $SNMP_OID) ) ]] && (( ret == 255 )); then
    echo 'UNKNOWN: SSH connect failed'
    exit 3
fi
if (( ret != 0 )); then
    echo 'UNKNOWN: Failed to get zpool data'
    exit 3
fi

#echo "$REPLY" >&2
echo "$REPLY" |awk \
    -v "WARNING_USAGE=$WARNING_USAGE" \
    -v "CRITICAL_USAGE=$CRITICAL_USAGE" \
'
$1 == "NAME" && $2 == "HEALTH" {
    parse = 1;
    next;
}
$1 == "NAME" && $2 == "USED" && $3 == "AVAIL" {
    parse = 2;
    next;
}
parse == 1 && NF == 2 {
    name = $1
    health[name] = $2
    all_names[name] = 1;
}
parse == 2 && NF == 3 {
    name = $1
    used[name] = $2;
    avail[name] = $3;
    all_names[name] = 1;
}

function increase_prio(current, target) {
    return (NAGIOS_STATUS_PRIO_TR[target] > NAGIOS_STATUS_PRIO_TR[current]) \
        ? target : current;
}

function human(input, mult, sep, _sym) {
    _sym = 1;
    while (input >= mult && _sym < HSYM_LEN) {
        _sym++;
        input = input / mult;
    }
    return sprintf("%.2lf%s%s", input, sep, HSYM[_sym]);
}

BEGIN {
    HSYM_LEN = split(" ,K,M,G,T,P", HSYM, ",");
}

END {
    NAGIOS_STATUS_TEXT[0] = "OK";
    NAGIOS_STATUS_TEXT[1] = "WARNING";
    NAGIOS_STATUS_TEXT[2] = "CRITICAL";
    NAGIOS_STATUS_TEXT[3] = "UNKNOWN";
    NAGIOS_STATUS_PRIO_TR[0] = 0;
    NAGIOS_STATUS_PRIO_TR[1] = 2;
    NAGIOS_STATUS_PRIO_TR[2] = 3;
    NAGIOS_STATUS_PRIO_TR[3] = 1;
    status = 0;
    output_err = "";
    output = "";
    perfdata = "";

    for (name in all_names) {
        cur_status = 0;
        cur_output = "";
        if (health[name] == "") {
            cur_output = cur_output "health ???";
            cur_status = increase_prio(cur_status, 3);
        }
        else if (health[name] != "ONLINE") {
            cur_output = cur_output health[name];
            cur_status = increase_prio(cur_status, 2);
        }
        else {
            cur_output = cur_output health[name];
        }
        cur_output = cur_output ", usage"
        if (used[name] == "" || avail[name] == "") {
            cur_output = cur_output " ???"
            perfdata = perfdata (perfdata == "" ? "" : " ") \
                "zpool." name ".used_bytes=U;;;;" \
                " zpool." name ".used_percent=U;;;0;100";
            cur_status = increase_prio(cur_status, 3);
        }
        else {
            size = used[name] + avail[name];
            used_perc = used[name] * 100 / size;
            cur_output = cur_output " " sprintf("%.2lf", used_perc) "%" \
                " = " human(used[name], 1024) "B/" human(size, 1024) "B" \
                " (" human(avail[name], 1024) "B free)"
            perfdata = perfdata (perfdata == "" ? "" : " ") \
                "zpool." name ".used_bytes=" used[name] "B;;;;" size \
                " zpool." name ".used_percent=" sprintf("%.6lf", used_perc) \
                "%;" WARNING_USAGE ";" CRITICAL_USAGE ";0;100";
            if (CRITICAL_USAGE != "" && used_perc >= CRITICAL_USAGE)
                cur_status = increase_prio(cur_status, 2);
            else if (WARNING_USAGE != "" && used_perc >= WARNING_USAGE)
                cur_status = increase_prio(cur_status, 1);
        }

        if (cur_status == 0)
            output = output (output == "" ? "" : " - ") name " " cur_output;
        else
            output = "**" name "** " cur_output (output == "" ? "" : " - ") output;

        status = increase_prio(status, cur_status);
    }

    if (output == "") {
        status = increase_prio(status, 3);
        output = "No zpool found!";
    }
    print NAGIOS_STATUS_TEXT[status] ": " output "|" perfdata;
    exit(status);
}
'