Misadventures of a Celtic Geek

Sometimes things that seem completely harmless just come and hit you over the head…

That’s what happened to me with Zabbix yesterday. I was going through some items and cleaning up, when suddenly, 4 hosts went off-line. Except that they hadn’t.

I couldn’t understand why Zabbix refused to see them (the agents were responding fine).

I finally found out that it was because of the way that Zabbix calculates the ’status’ item, which has a value of 0 if alls well, and 2 if the host is off-line.

Zabbix looks at the first item to be taken of the host, if that item returns an empty string, Zabbix decides that the host is dead and raises the alarm, even if the host has 150 other items all working perfectly. This bizzar to say the least, but workable. If this happens, a quick fix is to deactivate the offending Item, so that the first Item checked returns a value, then the host comes back

Any how, I thought I’d just document this in case anyone else starts loosing hair over the issue

En me baladant sur le net ce midi, je suis retombé sur la site web de mon tout premier emploie.

La Maison des Etudiants (1991-2003) était une association d’aide aux étudiants, qui grâce aux emplois jeunes, entre autre fournissait divers service aux étudiants adhérants de l’association. Notament les copies et l’informatique (principalement ce de quoi je m’occuper):

J’y étais entre 2001 et 2003, et l’expérience était pour le moins formateur,

-Premier Boulot
-Premier Linux
-Premiers projets aussi

Vers la fin j’avais même fait un premier déploiement sur les posts disponibles ‘grand public’, qui aurait pu être pire point de vue désastre ;).

Malheureusement, pile au moment où mon Emploi Jeunes arrivait à term, la fac à décider de faire couler l’asso pour reprendre l’activité, et c’est ainsi que s’est terminé une expérience que je n’oublirai sans doute jamais.

Un coucou à tout ceux qui se reconnaîtront de cette époque (y compris l’Afev et Velocampus, dés assos nés de la MDE et qui battent toujours de leurs propres ailes): Xavier, Claire, Laurent….

I’ve just been testing an install CD for enkix, our custom Debian installer, to make sure it works next week when I re-install some servers in Paris.

The problem is that our datacenter lacks a dhcp server (everythings static), whereas I had never tested enkix using static IPs before (all installs were done at the office).

Vmware was my poison of choice for this task, since it offers sevral network parameters: Bridged networking using the offices DHCP, net using it’s own DHCP, and a host only network using…. it’s own DHCP. Hmm… and what happens if you just don’t like DHCP? What if you want everything static? Or if you prefer Avahi? Or, as is in my case, you’re testing for a DHCP-less environment and DHCP is the last thing you want?

After a few fruitless searches on the web, the solution was revealed by probing /etc/vmware. In the network sub directories (vmnet0-vmnet8), those which have a DHCP server have a dhcp sub directory, the others don’t.

Solution: Just create a natted vmnet, then pop into the corresponding directory, rm -rf dhcp and /etc/init.d/vmware restart, problem solved.

One last thing: if you do this, please make a note of the network parameters before hand, since it’s always some funny value like 192.168.28.x

I can’t quite understand this.

In this day and age where pass by reference is the new black (ie, .net only passes by reference, java only passes base types by value), php has decided to be the black sheep (or not, depending on your point of view).

Using php 5, objects are passed by reference, always, which is logical, easier to manage and saves on stack space. OTOH arrays are passed by … value (unless forced with a &). Go figure.

Still trying to come to terms with this particular oddity.

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… is something I don’t want to experience.

I’m currently in the final stages of preparing a switch-over from a standard mail server to a virtual user based one, the transfer will be at just after 20:00, or in slightly more than half an hour.

Wish me luck!