Application Monitoring 4.4

OneGate allows Virtual Machine guests to push monitoring information to OpenNebula. Users and administrators can use it to gather metrics, detect problems in their applications, and trigger OneFlow elasticity rules.

OneGate Workflow Explained

OneGate is a server that listens to http connections from the Virtual Machines. OpenNebula assigns an individual token to each VM instance, and Applications running inside the VM use this token to send monitoring metrics to OneGate.

When OneGate checks the VM ID and the token sent, the new information is placed inside the VM's user template section. This means that the application metrics are visible from the command line, Sunstone, or the APIs.

OneGate Usage

First, the cloud administrator must configure and start the OneGate server.

Setup the VM Template

Your VM Template must set the CONTEXT/TOKEN attribute to “yes”.

CPU     = "0.5"
MEMORY  = "128"
 
DISK = [
  IMAGE_ID = "0" ]
NIC = [
  NETWORK_ID = "0" ]
 
CONTEXT = [
  TOKEN = "YES" ]

When this Template is instantiated, OpenNebula will automatically add the ONEGATE_URL context variable, and a token.txt will be placed in the context cdrom. This token.txt file is only accessible from inside the VM.

...
 
CONTEXT=[
  DISK_ID="1",
  ONEGATE_URL="http://192.168.0.1:5030/vm/0",
  TARGET="hdb",
  TOKEN="YES" ]

Push Metrics from the VM Guest

The contextualization cdrom should contain the context.sh and token.txt files.

<xterm> # mkdir /mnt/context # mount /dev/hdb /mnt/context # cd /mnt/context # ls context.sh token.txt # cat context.sh # Context variables generated by OpenNebula DISK_ID='1' ONEGATE_URL='http://192.168.0.1:5030/vm/0' TARGET='hdb' TOKEN='yes' # cat token.txt yCxieDUS7kra7Vn9ILA0+g== </xterm>

With that data, you can perform this http request message:

Request	PUT ONEGATE_URL
Headers	X-ONEGATE-TOKEN: token.txt contents
Body	Monitoring values, in the usual “ATTRIBUTE = VALUE” OpenNebula syntax

For example, using the curl command: <xterm> curl -X "PUT" http://192.168.0.1:5030/vm/0 --header "X-ONEGATE-TOKEN: yCxieDUS7kra7Vn9ILA0+g==" -d "APP_LOAD = 9.7" </xterm>

The new metric is stored in the user template section of the VM: <xterm> $ onevm show 0 … USER TEMPLATE APP_LOAD=“9.7”

</xterm>

Sample Script

#!/bin/bash
 
# -------------------------------------------------------------------------- #
# Copyright 2002-2013, OpenNebula Project (OpenNebula.org), C12G Labs        #
#                                                                            #
# Licensed under the Apache License, Version 2.0 (the "License"); you may    #
# not use this file except in compliance with the License. You may obtain    #
# a copy of the License at                                                   #
#                                                                            #
# http://www.apache.org/licenses/LICENSE-2.0                                 #
#                                                                            #
# Unless required by applicable law or agreed to in writing, software        #
# distributed under the License is distributed on an "AS IS" BASIS,          #
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   #
# See the License for the specific language governing permissions and        #
# limitations under the License.                                             #
#--------------------------------------------------------------------------- #
 
################################################################################
# Initialization
################################################################################
 
ERROR=0
 
if [ -z $ONEGATE_TOKEN ]; then
    echo "ONEGATE_TOKEN env variable must point to the token.txt file"
    ERROR=1
fi
 
if [ -z $ONEGATE_URL ]; then
    echo "ONEGATE_URL env variable must be set"
    ERROR=1
fi
 
if [ $ERROR = 1 ]; then
    exit -1
fi
 
TMP_DIR=`mktemp -d`
echo "" > $TMP_DIR/metrics
 
################################################################################
# Memory metrics
################################################################################
 
MEM_TOTAL=`grep MemTotal: /proc/meminfo | awk '{print $2}'`
MEM_FREE=`grep MemFree: /proc/meminfo | awk '{print $2}'`
MEM_USED=$(($MEM_TOTAL-$MEM_FREE))
 
MEM_USED_PERC="0"
 
if ! [ -z $MEM_TOTAL ] && [ $MEM_TOTAL -gt 0 ]; then
    MEM_USED_PERC=`echo "$MEM_USED $MEM_TOTAL" | \
        awk '{ printf "%.2f", 100 * $1 / $2 }'`
fi
 
SWAP_TOTAL=`grep SwapTotal: /proc/meminfo | awk '{print $2}'`
SWAP_FREE=`grep SwapFree: /proc/meminfo | awk '{print $2}'`
SWAP_USED=$(($SWAP_TOTAL - $SWAP_FREE))
 
SWAP_USED_PERC="0"
 
if ! [ -z $SWAP_TOTAL ] && [ $SWAP_TOTAL -gt 0 ]; then
    SWAP_USED_PERC=`echo "$SWAP_USED $SWAP_TOTAL" | \
        awk '{ printf "%.2f", 100 * $1 / $2 }'`
fi
 
 
#echo "MEM_TOTAL = $MEM_TOTAL" >> $TMP_DIR/metrics
#echo "MEM_FREE = $MEM_FREE" >> $TMP_DIR/metrics
#echo "MEM_USED = $MEM_USED" >> $TMP_DIR/metrics
echo "MEM_USED_PERC = $MEM_USED_PERC" >> $TMP_DIR/metrics
 
#echo "SWAP_TOTAL = $SWAP_TOTAL" >> $TMP_DIR/metrics
#echo "SWAP_FREE = $SWAP_FREE" >> $TMP_DIR/metrics
#echo "SWAP_USED = $SWAP_USED" >> $TMP_DIR/metrics
echo "SWAP_USED_PERC = $SWAP_USED_PERC" >> $TMP_DIR/metrics
 
################################################################################
# Disk metrics
################################################################################
 
/bin/df -k -P | grep '^/dev' > $TMP_DIR/df
 
cat $TMP_DIR/df | while read line; do
    NAME=`echo $line | awk '{print $1}' | awk -F '/' '{print $NF}'`
 
    DISK_TOTAL=`echo $line | awk '{print $2}'`
    DISK_USED=`echo $line | awk '{print $3}'`
    DISK_FREE=`echo $line | awk '{print $4}'`
 
    DISK_USED_PERC="0"
 
    if ! [ -z $DISK_TOTAL ] && [ $DISK_TOTAL -gt 0 ]; then
        DISK_USED_PERC=`echo "$DISK_USED $DISK_TOTAL" | \
            awk '{ printf "%.2f", 100 * $1 / $2 }'`
    fi
 
    #echo "DISK_TOTAL_$NAME = $DISK_TOTAL" >> $TMP_DIR/metrics
    #echo "DISK_FREE_$NAME = $DISK_FREE" >> $TMP_DIR/metrics
    #echo "DISK_USED_$NAME = $DISK_USED" >> $TMP_DIR/metrics
    echo "DISK_USED_PERC_$NAME = $DISK_USED_PERC" >> $TMP_DIR/metrics
done
 
################################################################################
# PUT command
################################################################################
 
curl -X "PUT" --header "X-ONEGATE-TOKEN: `cat $ONEGATE_TOKEN`" $ONEGATE_URL \
    --data-binary @$TMP_DIR/metrics