My posts about issues concerning Linux OS and network administration

Monitoring postfix with Zabbix (LTS version 3.0)

As we’ve built new monitoring system based on Zabbix LTS version 3.0 I also was looking for solution how to monitor postfix servers. I’ve found few articles regarding this issue but they were either outdated or not very effective.

I decided to take the best from what I’ve found but build an own strategy.

The whole solution consists of several different parts:

    • pygtail software
      This one reads the lines of mail log (this tools is written in Python and works great on Centos 6 and Centos 7. It doesn’t run on Centos 5 due to older Python libraries. You can download my spec file for Centos 6/7 here if you want to create an RPM package,
    • pflogsumm script
      This script is part of postfix-perl-scripts package on Centos 6 and 7 and can read the Postfix logs and create nice summary. We’d use this one to get the summary and parse it for interesting values to be further read by Zabbix
    • Zabbix temlate for Postfix monitoring
    • create userparameter_postfix.conf file under /etc/zabbix/zabbix_agent.d with this content (you also have to enable remote commands to be run on Zabbix clients by adding enableEnableRemoteCommands=1 to main config file /etc/zabbix/zabbix_agentd.conf):
      # Postfix user parameter
      UserParameter=postfix.pfmailq,mailq | grep -v "Mail queue is empty" | grep -c '^[0-9A-Z]'
      UserParameter=postfix[*],sudo /usr/local/bin/zabbix-postfix-stats.sh $1
      UserParameter=postfix.update_data,sudo /usr/local/bin/zabbix-postfix-stats.sh
      
    • we need to add this line to /etc/sudoers to grant zabbix user access to run the main script with root permissions (otherwise zabbix user would need access to read mail logs):
      zabbix  ALL=NOPASSWD: /usr/local/bin/zabbix-postfix-stats.sh *
      
    • simple bash script which uses pygtail and pflogsumm and gets the interesting data from Postfix log to by further read by Zabbix:
      #!/usr/bin/env bash
      
      MAILLOG=/var/log/maillog
      PFOFFSETFILE=/tmp/zabbix-postfix-offset.dat
      PFSTATSFILE=/tmp/postfix_statsfile.dat
      TEMPFILE=$(mktemp)
      PFLOGSUMM=/usr/sbin/pflogsumm
      PYGTAIL=/usr/bin/pygtail
      
      # list of values we are interested in
      PFVALS=( 'received' 'delivered' 'forwarded' 'deferred' 'bounced' 'rejected' 'held' 'discarded' 'reject_warnings' 'bytes_received' 'bytes_delivered' )
      
      # write result of running this script
      write_result () {
      
              echo "$2"
              exit $1
      
      }
      
      # check for binaries we need to run the script
      if [ ! -x ${PFLOGSUMM} ] ; then
              echo "ERROR: ${PFLOGSUMM} not found"
              exit 1
      fi
      
      if [ ! -x ${PYGTAIL} ] ; then
              echo "ERROR: ${PYGTAIL} not found"
              exit 1
      fi
      
      if [ ! -r ${MAILLOG} ] ; then
              echo "ERROR: ${MAILLOG} not readable"
              exit 1
      fi
      
      
      # check whether file exists and the write permissions are granted
      if [ ! -w "${PFSTATSFILE}" ]; then
              touch "${PFSTATSFILE}" && chown zabbix:zabbix "${PFSTATSFILE}" > /dev/null 2>&1
      
              if [ ! $? -eq 0 ]; then
                      result_text="ERROR: wrong exit code returned while creating file ${PFSTATSFILE} and setting its owner to zaabbix:zabbix"
                      result_code="1"
                      write_result "${result_code}" "${result_text}"
              fi
      fi
      
      # read specific value from data file and print it
      readvalue () {
              local $key
              key=$(echo ${PFVALS[@]} | grep -wo $1)
              if [ -n "${key}" ]; then
                      value=$(grep -e "^${key};" "${PFSTATSFILE}" | cut -d ";" -f2)
                      echo "${value}"
      
              else
                      rm "${TEMPFILE}"
                      result_text="ERROR: could not get value \"$1\" from ${PFSTATSFILE}"
                      result_code="1"
                      write_result "${result_code}" "${result_text}"
              fi
      }
      
      # update value  in data file
      updatevalue() {
              local $key
              local $pfkey
      
              key=$1
              pfkey=$(echo "$1" | tr '_' ' ')
      
              # convert value to bytes
              value=$(grep -m 1 "$pfkey" $TEMPFILE | awk '{print $1}' | awk '/k|m/{p = /k/?1:2}{printf "%d\n", int($1) * 1024 ^ p}')
      
              # update values in data file
              old_value=$(grep -e "^${key};" "${PFSTATSFILE}" | cut -d ";" -f2)
              if [ -n "${old_value}" ]; then
                      sed -i -e "s/^${key};${old_value}/${key};$((${old_value}+${value}))/" "${PFSTATSFILE}"
              else
                      echo "${key};${value}" >> "${PFSTATSFILE}"
      
              fi
      }
      
      # is there a requests for specific value or do we update all values ?
      if [ -n "$1" ]; then
              readvalue "$1"
      else
              # read the new part of mail log and read it with pflogsumm to get the summary
              "${PYGTAIL}" -o"${PFOFFSETFILE}" "${MAILLOG}" | "${PFLOGSUMM}" -h 0 -u 0 --no_bounce_detail --no_deferral_detail --no_reject_detail --no_smtpd_warnings --no_no_msg_size > "${TEMPFILE}" 2>/dev/null
      
              if [ ! $? -eq 0 ]; then
                      result_text="ERROR: wrong exit code returned while running  \"${PYGTAIL}\" -o\"${PFOFFSETFILE}\" \"${MAILLOG}\" | \"${PFLOGSUMM}\" -h 0 -u 0 --no_bounce_detail --no_deferral_detail --no_reject_detail --no_smtpd_warnings --no_no_msg_size > \"${TEMPFILE}\" 2>/dev/null"
                      result_code="1"
                      write_result "${result_code}" "${result_text}"
              fi
      
              # update all values from pflogsumm summary
              for i in "${PFVALS[@]}"; do
                      updatevalue "$i"
              done
      
              result_text="OK: statistics updated"
              result_code="0"
              write_result "${result_code}" "${result_text}"
      fi
      
      rm "${TEMPFILE}"
      
      

This is a summary how the whole thing works:

  1. All items from Zabbix postfix template refer to user parameters defined in userparameter_postfix.conf file. These are read on zabbix client and triggers the launch of the defined bash script zabbix-postfix-stats.sh
  2. There is a item called ‘Postfix data update request’ in the template which is run every minute. This one calls the script zabbix-postfix-stats.sh without any arguments which makes the script to update all the statistics from the Postfix mail log file. To parse the log file we need both pygtail and pflogsumm tools – both mentioned at the beginning.
  3. The rest of template items are not run so often and causes the script zabbix-postfix-stats.sh to be run with a specific argument depending on item type. If the postfix statistics were already made the value which is requested by each item is returned.

 

Posted in Monitoring

4 Responses to “Monitoring postfix with Zabbix (LTS version 3.0)”

  • Admiral says:

    This doesn’t work on FreeBSD 10.3
    …”: unterminated substitute pattern
    sed: 1: “s/^held;

    …”: unterminated substitute pattern
    sed: 1: “s/^discarded;

    …”: unterminated substitute pattern
    sed: 1: “s/^reject_warnings;

    …”: unterminated substitute pattern
    sed: 1: “s/^bytes_received;

    …”: unterminated substitute pattern
    sed: 1: “s/^bytes_delivered;

    …”: unterminated substitute pattern
    OK: statistics updated

    Gives me no stats in Zabbix

  • Joshua Flintofferson says:

    Cannot import template “Template App Postfix”, linked template “Template SMTP Server” does not exist. [conf.import.php:176 → CFrontendApiWrapper->import() → CApiWrapper->__call() → CFrontendApiWrapper->callMethod() → CApiWrapper->callMethod() → CFrontendApiWrapper->callClientMethod() → CLocalApiClient->callMethod() → call_user_func_array() → CConfiguration->import() → CConfigurationImport->import() → CConfigurationImport->processTemplates() → CTemplateImporter->import() in include/classes/import/CConfigurationImport.php:547]

  • Rob says:

    Hello, i have same problem like Joshua:

    Cannot import template “Template App Postfix”, linked template “Template SMTP Server” does not exist.

    What do?


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