Server Monitoring with Munin and Monit on Ubuntu 16.04 LTS (Xenial Xerus) - Page 2

This tutorial exists for these OS versions

On this page

  1. 6 Install and Configure Monit
  2. 7 Configure Monit in ISPConfig 
  3. 8 Links

6 Install and Configure Monit

To install Monit, we do this:

apt-get -y install monit

Now we must edit /etc/monit/monitrc. The default /etc/monit/monitrc has lots of examples, and you can find more configuration examples on http://mmonit.com/monit/documentation/. However, in my case I want to monitor proftpd, sshd, mysql, apache, and postfix, I want to enable the Monit web interface on port 2812, I want a https web interface, I want to login to the web interface with the username admin and the password howtoforge, and I want Monit to send email alerts to root@localhost, so my file looks like this (I've added examples for other daemons to the configuration so that you can adjust the file to your needs):

cp /etc/monit/monitrc /etc/monit/monitrc_orig
cat /dev/null > /etc/monit/monitrc
nano /etc/monit/monitrc
set daemon 60
set logfile syslog facility log_daemon
set mailserver localhost
set mail-format { from: [email protected] }
set alert root@localhost
set httpd port 2812 and
 SSL ENABLE
 PEMFILE /var/certs/monit.pem
 allow admin:howtoforge

check process sshd with pidfile /var/run/sshd.pid
 start program "/usr/sbin/service ssh start"
 stop program "/usr/sbin/service ssh stop"
 if failed port 22 protocol ssh then restart
 if 5 restarts within 5 cycles then timeout

check process apache with pidfile /var/run/apache2/apache2.pid
 group www
 start program = "/usr/sbin/service apache2 start"
 stop program = "/usr/sbin/service apache2 stop"
 if failed host localhost port 80 protocol http
 and request "/monit/token" then restart
 if cpu is greater than 60% for 2 cycles then alert
 if cpu > 80% for 5 cycles then restart
 if totalmem > 500 MB for 5 cycles then restart
 if children > 250 then restart
 if loadavg(5min) greater than 10 for 8 cycles then stop
 if 3 restarts within 5 cycles then timeout
 
#check process mysql with pidfile /var/run/mysqld/mysqld.pid
# group database
# start program = "/usr/sbin/service mysql start"
# stop program = "/usr/sbin/service mysql stop"
# if failed host 127.0.0.1 port 3306 then restart
# if 5 restarts within 5 cycles then timeout

#check process proftpd with pidfile /var/run/proftpd.pid
# start program = "/usr/sbin/service proftpd start"
# stop program = "/usr/sbin/service proftpd stop"
# if failed port 21 protocol ftp then restart
# if 5 restarts within 5 cycles then timeout
#
#check process postfix with pidfile /var/spool/postfix/pid/master.pid
# group mail
# start program = "/usr/sbin/service postfix start"
# stop program = "/usr/sbin/service postfix stop"
# if failed port 25 protocol smtp then restart
# if 5 restarts within 5 cycles then timeout
#
#check process nginx with pidfile /var/run/nginx.pid
# start program = "/usr/sbin/service nginx start"
# stop program = "/usr/sbin/service nginx stop"
# if failed host 127.0.0.1 port 80 then restart
#
#check process memcached with pidfile /var/run/memcached.pid
# start program = "/usr/sbin/service memcached start"
# stop program = "/usr/sbin/service memcached stop"
# if failed host 127.0.0.1 port 11211 then restart
#
#check process pureftpd with pidfile /var/run/pure-ftpd/pure-ftpd.pid
# start program = "/usr/sbin/service pure-ftpd-mysql start"
# stop program = "/usr/sbin/service pure-ftpd-mysql stop"
# if failed port 21 protocol ftp then restart
# if 5 restarts within 5 cycles then timeout
#
#check process named with pidfile /var/run/named/named.pid
# start program = "/usr/sbin/service bind9 start"
# stop program = "/usr/sbin/service bind9 stop"
# if failed host 127.0.0.1 port 53 type tcp protocol dns then restart
# if failed host 127.0.0.1 port 53 type udp protocol dns then restart
# if 5 restarts within 5 cycles then timeout
#
#check process ntpd with pidfile /var/run/ntpd.pid
# start program = "/usr/sbin/service ntp start"
# stop program = "/usr/sbin/service ntp stop"
# if failed host 127.0.0.1 port 123 type udp then restart
# if 5 restarts within 5 cycles then timeout
#
#check process mailman with pidfile /var/run/mailman/mailman.pid
# group mail
# start program = "/usr/sbin/service mailman start"
# stop program = "/usr/sbin/service mailman stop"
#
#check process amavisd with pidfile /var/run/amavis/amavisd.pid
# group mail
# start program = "/usr/sbin/service amavis start"
# stop program = "/usr/sbin/service amavis stop"
# if failed port 10024 protocol smtp then restart
# if 5 restarts within 5 cycles then timeout
#
#check process courier-imap with pidfile /var/run/courier/imapd.pid
# group mail
# start program = "/usr/sbin/service courier-imap start"
# stop program = "/usr/sbin/service courier-imap stop"
# if failed host localhost port 143 type tcp protocol imap then restart
# if 5 restarts within 5 cycles then timeout
#
#check process courier-imap-ssl with pidfile /var/run/courier/imapd-ssl.pid
# group mail
# start program = "/usr/sbin/service courier-imap-ssl start"
# stop program = "/usr/sbin/service courier-imap-ssl stop"
# if failed host localhost port 993 type tcpssl sslauto protocol imap then restart
# if 5 restarts within 5 cycles then timeout
#
#check process courier-pop3 with pidfile /var/run/courier/pop3d.pid
# group mail
# start program = "/usr/sbin/service courier-pop start"
# stop program = "/usr/sbin/service courier-pop stop"
# if failed host localhost port 110 type tcp protocol pop then restart
# if 5 restarts within 5 cycles then timeout
#
#check process courier-pop3-ssl with pidfile /var/run/courier/pop3d-ssl.pid
# group mail
# start program = "/usr/sbin/service courier-pop-ssl start"
# stop program = "/usr/sbin/service courier-pop-ssl stop"
# if failed host localhost port 995 type tcpssl sslauto protocol pop then restart
# if 5 restarts within 5 cycles then timeout
#
#check process dovecot with pidfile /var/run/dovecot/master.pid
# group mail
# start program = "/usr/sbin/service dovecot start"
# stop program = "/usr/sbin/service dovecot stop"
# if failed host localhost port 143 type tcp protocol imap then restart
# if 5 restarts within 5 cycles then timeout

The configuration file is pretty self-explaining; if you are unsure about an option, take a look at the Monit documentation: http://mmonit.com/monit/documentation/monit.html

In the apache part of the Monit configuration you find this:

   if failed host localhost port 80 protocol http
      and request "/monit/token" then restart

which means that Monit tries to connect to localhost on port 80 and tries to access the file /monit/token which is /var/www/html/monit/token because our web site's document root is /var/www/html. If Monit doesn't succeed it means Apache isn't running, and Monit is going to restart it. Now we must create the file /var/www/html/monit/token and write some random string into it:

mkdir /var/www/html/monit
echo "hello" > /var/www/html/monit/token

Next, we create the pem cert (/var/certs/monit.pem) we need for the SSL-encrypted Monit web interface:

mkdir /var/certs
cd /var/certs

We need an OpenSSL configuration file to create our certificate. It can look like this:

nano /var/certs/monit.cnf
# create RSA certs - Server

RANDFILE = ./openssl.rnd

[ req ]
default_bits = 2048
encrypt_key = yes
distinguished_name = req_dn
x509_extensions = cert_type

[ req_dn ]
countryName = Country Name (2 letter code)
countryName_default = MO

stateOrProvinceName             = State or Province Name (full name)
stateOrProvinceName_default     = Monitoria

localityName                    = Locality Name (eg, city)
localityName_default            = Monittown

organizationName                = Organization Name (eg, company)
organizationName_default        = Monit Inc.

organizationalUnitName          = Organizational Unit Name (eg, section)
organizationalUnitName_default  = Dept. of Monitoring Technologies

commonName                      = Common Name (FQDN of your server)
commonName_default              = server.monit.mo

emailAddress                    = Email Address
emailAddress_default            = [email protected]

[ cert_type ]
nsCertType = server

Now we create the certificate like this:

openssl req -new -x509 -days 365 -nodes -config ./monit.cnf -out /var/certs/monit.pem -keyout /var/certs/monit.pem
openssl gendh 1024 >> /var/certs/monit.pem
openssl x509 -subject -dates -fingerprint -noout -in /var/certs/monit.pem
chmod 600 /var/certs/monit.pem

Finally, we can start Monit:

service monit restart

Now point your browser to https://www.example.com:2812/ (make sure port 2812 isn't blocked by your firewall), log in with admin and howtoforge, and you should see the Monit web interface. It should look like this:

Monit services.

(Main Screen)

Monit system status.

(System Status Page)

Depending on your configuration in /etc/monit/monitrc monit will restart your services if they fail and send notification emails if process IDs of services change, etc.

To get the Monit status on the shell, run the "monit status" command:

monit status

The command will show the status of all monitored services.

Check Monit status on the commandline.

7 Configure Monit in ISPConfig 

The ISPConfig Server Control Panel can show Monit data within it's Monitor module. To enable that function in ISPConfig, login to ISPConfig as Administrator (admin) user, go to System > Server config, fill in the URL, username and password for Monit as shown below.

The ISPConfig Monit settings.

8 Links

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