Re: [monit] Monit 5.0.2 question

[Martin Pala]

The problem is that there is no reliable way how to get correct FQDN.  
There is unreliable interface getdomainname() which returns on many  
platforms empty string or often default domains like "localdomain",  
"mydomain" when no other specific domain was set during system  
installation. The getdomainname() takes the value on some platforms  
from sysctl, on other platforms from file in /etc/ and on other  
platforms it's completely ignored. The name service  lookup is not  
reliable as well - it depends on how the name service was set (usually  
NSS switch uses local files first which often have the shortname in  
front of longname for the given IP address and thus return often  
shortname first).

There are at least two possible solutions:

1.) set the machine hostname to FQDN instead of shortname (usually in / 
etc/hostname, but it's platform depended) ... the hostname can be  
checked with "uname -n" - monit's $HOST will then expand to FQDN

2.) expand the $HOST in monitrc to FQDN hostname manually ... in mail- 
format{} statement simply set the "from:" option to FQDN address, the  
"set mailserver" option allows to specify the hostname which should be  
used in SMTP communication (message-id header and HELO/EHLO command)  
this way:
  set mailserver foo.bar.baz using hostname "my.monit.host"

Other software usually handles the problem same way - for example MTAs  
like Postfix, Sendmail require manual configuration of domain name  
when "uname -n" is not fully qualified.


Martin



On May 13, 2009, at 5:51 PM, Aleksander Kamenik wrote:

> David Paper wrote:
> > $HOST appears to be the short name that the host is known by.  This  
> > presents a problem when there are two hosts that have identical  
> > short names, but different subdomains like:
>
> Good point. Though I've tried to always have different names be  
> cause of this kind of problems.
>
> > On SuSE linux, 'hostname' returns just foo07.  'hostname -f'  
> > returns the fully qualified domain name.
>
> On Fedora 10 hostname returns the fqdn. -f returns  
> localhost.localdomain for me. Do you by chance know a more reliable  
> way to get the FQDN? I'm asking be cause I've had this problem when  
> writing shell scripts which should work on several distros.
>
> > Is it possible to tell monit in the monitrc file either to use the  
> > FQDN of the host, or to specify what the FQDN is?
>
> I'd prefer using the FQDN instead of the short host name too.
>
> Regards,
>
> --
>
> Aleksander Kamenik
> System Administrator
> Krediidiinfo AS
> an Experian Company
> Phone: +372 665 9649
> Email: address@hidden
>
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> http://www.experiangroup.com/
>
>
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