Enable SMTP on max OS

sudo postfix start

java send mail using ubuntu local sendmail smtp

import java.util.Properties;

import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;


public static void main(String[] args) {

String to="recipient@example.com";
String from="sender@example.com";

Properties props = new Properties();
Session session = Session.getDefaultInstance(props, null);

// props.put("mail.smtp.host", "localhost"); // optional

String msgBody = "Sending email using JavaMail API...";

try {
Message msg = new MimeMessage(session);
msg.setFrom(new InternetAddress(from, "NoReply"));
msg.addRecipient(Message.RecipientType.TO,
new InternetAddress(to, "Mr. Recipient"));
msg.setSubject("Welcome To Java Mail API");
msg.setText(msgBody);
Transport.send(msg);
System.out.println("Email sent successfully...");

} catch (AddressException e) {
throw new RuntimeException(e);
} catch (MessagingException e) {
throw new RuntimeException(e);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}

}

Find largest directories on Linux

sudo du -sh * | sort -nr | head -n10

Setup Zabbix on Ubuntu for Postgresql connection

1. Install unixODBC >sudo apt-get install unixODBC
2. Install postgresql odbc driver >sudo apt-get install postgresql-odbc
3. Setup /etc/odbc.ini
[test]
Description = 192.168.8.220 test
Driver = postgresql
Servername = 192.168.8.220
Port = 5432
Database = db_name

4. Setup /etc/odbcinst.ini
[postgresql]
Description = ODBC for postgresql
Driver = /usr/lib/x86_64-linux-gnu/odbc/psqlodbca.so
Setup = /usr/lib/x86_64-linux-gnu/odbc/libodbcpsqlS.so

Test:
>isql test your_name your_password -v

In Zabbix, add database monitor:
key = db.odbc.select[some_name,test]

Postgresql usage notes

Revoke:

    REVOKE ALL ON DATABASE db_name FROM user_name;
    revoke all on all tables in schema public from zabbix;

Readonly User:

    revoke all on schema public from public;
    create role zabbix login password 'some_pass';
    grant usage on schema public to zabbix;
    grant select on public.some_table to zabbix;

When you create a new database, any role is allowed to create objects in the public schema. To remove this possibility, you may issue immediately after the database creation:

REVOKE ALL ON schema public FROM public;

Edit: after the above command, only a superuser may create new objects inside the public schema, which is not practical. Assuming a non-superuser foo_user should be granted this privilege, this should be done with:

GRANT ALL ON schema public TO foo_user;

Configure Zabbix to sent alert email

Setup the host to be monitored


Setup Media Type, in this case, use email and local "sendmail" smtp server.  Remember to use 127.0.0.1 on the SMTP server settings.  Otherwise, it may have connection problem.



Ensure the User media email is enabled.



Ensure action is enabled.




Set the trigger.

Connects zabbix server to agent

* Remember to setup the zabbix-agent configuration to listen to the
right server IP and other settings.

log: /var/log/zabbix-agent/zabbix_agentd.log
config: /etc/zabbix/zabbix_agentd.conf

Check opened ports

netstat -anltp | grep "LISTEN"

ssh-copy-id copy id to remote machine

usage> ssh-copy-id -p 1337 your_name@remote_host

Try Zenoss

http://www.nerdnightlax.com/zenoss-install-on-ubuntu-desktop-12-0-4/

Setup Cacti for monitoring

http://www.itzgeek.com/how-tos/linux/ubuntu-how-tos/setup-cacti-network-monitoring-tool-on-ubuntu-14-04-linux-mint-17.html#axzz3LN2UZ8er