Postfix exporter with docker and prometheus.

in previous article we setup mailcow server with mailcow dockerized

Now we configure monitoring for this server(postfix) with promethes exporter,prometheus,grafana.

Setup prometheus exporter

mkdir -p /etc/prometheus/exporters/postfix

Create docker-compose file(docker-compose.yml)

version: '3.5'
services:
  exporter_postfix:
    image: "devsadds/exporter_postfix:2.0.0"
    volumes:
      - "/var/lib/docker/volumes/YOU_DOCKER_VOLUME_FOR_POSTFIX//_data/public/showq:/var/spool/postfix/public/showq:ro"
      - "/var/log/dockers/postfix/docker-postfix.log:/var/log/maillog:ro"
    ports:
      - "10.48.0.109:9154:9154"
    stdin_open: true
    tty: true
    restart: always

Set Postfix logs to rsyslog in docker-compose yml.

  logging:
    driver: syslog
    options:
      syslog-address: "udp://127.0.0.1:515"
      tag: "docker-postfix-{{.Name}}"

Restart postfix container with docker-compose.

Configure rsyslog for docker logs(postfix)

Install rsyslog from repo(example for ubuntu 20.04 ).

echo 'deb http://download.opensuse.org/repositories/home:/rgerhards/xUbuntu_20.04/ /' | sudo tee /etc/apt/sources.list.d/home:rgerhards.list
curl -fsSL https://download.opensuse.org/repositories/home:rgerhards/xUbuntu_20.04/Release.key | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/home:rgerhards.gpg > /dev/null
sudo apt update
sudo apt install rsyslog rsyslog-mmjsonparse rsyslog-mmnormalize

Change rsyslog configs

cat << OEF > /etc/rsyslog.d/docker_postfix.conf
module(load="imudp")
input(type="imudp" port=["515","20515"] device="lo" rcvbufSize="3m")
\$template t_docker_postfix, "%msg%"
if ( \$syslogtag startswith "docker-postfix")   then {action(type="omfile" file="/var/log/dockers/postfix/docker-postfix.log" template="t_docker_postfix" ) stop }
OEF

Create dir

mkdir -p /var/log/dockers/postfix/

Edit /etc/rsyslog.conf

##MODULES
module(load="imuxsock") # provides support for local system logging
module(load="imklog")   # provides kernel logging support
#module(load="imfile")
module(load="mmnormalize")
module(load="mmjsonparse")
#### GLOBAL DIRECTIVES
$ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat
#
# Set the default permissions for all log files.
#
$FileOwner root
$FileGroup adm
$FileCreateMode 0640
$DirCreateMode 0755
$Umask 0022
#
# Where to place spool and state files
#
$WorkDirectory /var/spool/rsyslog
#
# Include all config files in /etc/rsyslog.d/
#
$IncludeConfig /etc/rsyslog.d/*.conf
#### RULES
#
# First some standard log files.  Log by facility.
#
auth,authpriv.*     /var/log/auth.log
*.*;auth,authpriv.none    -/var/log/syslog
#cron.*       /var/log/cron.log
daemon.*      -/var/log/daemon.log
kern.*        -/var/log/kern.log
lpr.*         -/var/log/lpr.log
mail.*        -/var/log/mail.log
user.*        -/var/log/user.log
#
# Logging for the mail system.  Split it up so that
# it is easy to write scripts to parse these files.
#
mail.info     -/var/log/mail.info
mail.warn     -/var/log/mail.warn
mail.err      /var/log/mail.err
#
# Some "catch-all" log files.
#
*.=debug;\
  auth,authpriv.none;\
  news.none;mail.none -/var/log/debug
*.=info;*.=notice;*.=warn;\
  auth,authpriv.none;\
  cron,daemon.none;\
  mail,news.none    -/var/log/messages
#
# Emergencies are sent to everybody logged in.
#
*.emerg       :omusrmsg:*

Restart rsyslog

systemctl restart rsyslog && systemctl status rsyslog

See logs in dir

tail -f /var/log/dockers/postfix/*.log

Start exporter

cd /etc/prometheus/exporters/postfix
docker-composeu up -d

Visit page in browser

http://10.48.0.109:9154/metrics

Create Section in prometheus and add exporter

  - job_name: "exporter_postfix"
    scrape_interval: 10s
    file_sd_configs:
      - files:
        - '/etc/prometheus/file_sd_configs/exporter_postfix/*.yml'

Create dir for exporter inventory file

mkdir -p /etc/prometheus/file_sd_configs/exporter_postfix/

Create Inventory file

/etc/prometheus/file_sd_configs/exporter_postfix/prod.yml

- targets:
  - "10.48.0.109:9154"
  labels:
    job: exporter_postfix
    env: prod

Reload prometheus(i use docker)

reload_prometheus() {
  nginx_container=$(docker ps | grep 'mon.*nginx' | awk '{print $NF}')
  docker exec -i -u 0 ${nginx_container} sh -c "curl -s -X POST http://prometheus:9090/prometheus/-/reload"
}

Import dashboard in grafana with id 10013

Profit