Servers & Ops on iniy.org

Guide to limits.conf / ulimit /open file descriptors under linux

Fri, 04 Jul 2014 18:43:00 +0000

Why does linux have an open-file-limit?

The open-file-limit exists to prevent users/process to use up all resources on a machine. Every file-descriptor uses a certain amount of RAM and a malicious or malfunctioning program could bring down the whole server.

Informatica 9.1 Installation could not start _AdminConsole

Wed, 08 Aug 2012 13:53:07 +0000

Installing Informatica with the installer was straightforward, but for some strange reason the adminconsole could not be started. Here the output I found in the Logfile:

INFA_HOME/tomcat/logs/node.log
 2012-08-08 12:17:45,294 ERROR [Thread 6 of 6 in DomainServiceThreadPool] [SPC_10013] Prozess für Dienst _AdminConsole konnte nicht gestartet werden.
 2012-08-08 12:27:41,524 ERROR [Thread 6 of 6 in DomainServiceThreadPool] [SPC_10013] Prozess für Dienst _AdminConsole konnte nicht gestartet werden.
 2012-08-08 12:42:07,275 ERROR [Thread 6 of 6 in DomainServiceThreadPool] [SPC_10013] Prozess für Dienst _AdminConsole konnte nicht gestartet werden.

this is not very helpful, but in the following logfile I found a clue:

Glassfish Directory Deployment (explode Ear)

Wed, 04 Jul 2012 14:12:27 +0000

Recently I was struggeling with glassfish directory deployment. Actually it is quite easy:

unzip the ear-File (eg. example.ear) to a directory without .ear
then go into this directory and unzip all war and jar files to directories named _jar and _war (only on this directory level, don’t touch the files in /lib)
now copy the folder into your domains-autodeploy-folder

For more convenience, use this script. I think it is selfexplaining.

Glassfish 3.1.1 increase asadmin deployment timeout

Thu, 01 Mar 2012 16:48:18 +0000

Recently I was wondering why the deployment of a EAR-File on Glassfish 3.1.1 over the Web-Administration-Console or with asadmin took very very long in compare to local deployment with eclipse. The EAR-File is about 50 MB of size and contains a complex web-application. With eclipse deployment takes about 20 seconds. With administration-console or with asadmin the deployment takes more than 10 minutes. As the default deployment timeout value of asadmin is 600 seconds i even wasn’t able to deploy it at all.

Installing Glassfish 3.1 on headless Centos 5.5

Thu, 10 Mar 2011 09:01:09 +0000

i run into some problems installing glassfish on a centos server without X-Windows. You can use the glassfish installer, but actually just unzipping the glassfish-zip is the easier method.

Method 1: Installing just with a zip file (easy method)

1. you have to get a java sdk and install (i used the rpm provided by oracle)
2. get the glassfish zip-file install package

My first steps with Solaris

Tue, 30 Nov 2010 22:06:37 +0000

For some time now a friend of mine kept nagging me about how cool Solaris were and what nice features like ZFS and everthing it had. As I was using Debian Linux for a really long time and was absolutely satisfied in all situations I didn’t give Solaris much of a thought. But recently I decided to give it a chance and try something new. So here are my first experiences and tipps.

OTRS Installation on Debian Linux Lenny

Tue, 30 Nov 2010 22:05:45 +0000

Requirements

A Debian Lenny Basic Installation

Install OTRS over apt-get

This part is easy

apt-get install otrs2

First Test

Point your browser to your IP (for example 192.168.1.123) /otrs and you should see the OTRS Login

nagios nsca wrapper

Tue, 30 Nov 2010 21:56:29 +0000

nsca vs. nrpe

Personally i favor nrpe as I can control at a central point which checks are really run. I can have 30 checks in the config but, use only 5 of them. With nsca you have to adjust the cronjob-list on every server and have no central option.

nagios checks too slow

Tue, 30 Nov 2010 21:51:12 +0000

lately i came across a really dumb problem. Our nagios server sucked like hell and I couldn’t find the source of the problem. I was tuning nagios-parameters but nothing changed. The server had low load and cpu-usage, but the checks were delayed about 15-30 minutes (should be checked every 2 minutes). Then I found the solution. nagios active hostchecks YOU HAVE TO DISABLE THIS CRAP. In Nagios 2.x the hostchecks are serial, thus delaying all other checks, while checking. With some hundreds hosts it can happen fast, that the server is almost only checking the hosts and not doing anything else.

nfs: Stale File Handle with LVM partitions

Tue, 12 Oct 2010 09:24:57 +0000

recently I was having a problem with NFS. I wanted to export a quite large NFS-Volume (20TB) and when I tried to mount it on the client there was always the error

nfs: Stale File Handle

I couldn’t find the error and read some articles which indicated perhaps a corrupted underlying filesystem. Fearing the worst i wanted to do a fsck, but as the server currently is under heavy use this was no option. Luckily i found the next article which explains, that with LVM-Volumes one has to set a “fsid” Option or the export/mount could fail.

Mini-Howto: SNMP (Simple Network Management Protocol)

Thu, 21 Jan 2010 12:33:06 +0000

This Howto covers some SNMP Basics and examples how you can read some values

Introduction

The “Simple Network Management Protocol” is a powerful possibility to query network-devices for information, or even to manage them. It’s often also a security risk. As SNMP is a bit difficult to use at the beginning some administrators just skip over it. This can lead to security holes, when SNMP is activated by default on devices. For example on some HP-Switches I configured the default setting for SNMP was set to “read + write” for “public”. SNMP was limited to the local network, but still this enables all connected servers to shutdown ports and have other fun as they wanted. Often the configuration is like that to enable some configuration tools to control the switches.

Installing OTRS on CentOS 5

Sat, 26 Dec 2009 18:44:50 +0000

The rpm-packages for CentOS can easily be downloaded from http://otrs.org/download/ . Install with yum

wget http://ftp.otrs.org/pub/otrs/RPMS/fedora/4/otrs-2.4.5-01.noarch.rpm
yum install --nogpgcheck otrs-2.4.5-01.noarch.rpm

Don’t forget to disable selinux.

call in your browser http://yourserver.com/otrs/installer.pl and setup the database.

Now install the otrs cronjobs

sudo -u otrs /opt/otrs/bin/Cron.sh

this installs the otrs cronjobs in /var/spool/cron/otrs

Installing OpenBSD 64Bit on a Software Raid 1 (Mirroring)

Sun, 27 Sep 2009 11:34:54 +0000

Credits

This very good article is written by Marcus Redivo.
http://www.eclectica.ca/howto/openbsd-software-raid-howto.php

I added a warning to stress one point (see red font) which took me 5 hours to find the error, the rest is the orginal tutorial, have fun.

Build your own Debian Packages

Wed, 08 Jul 2009 14:28:09 +0000

Until now when I wrote some scripts I always copied them directly to the Servers .I always thought: “It would be really cool if this were a Debian Package”. I played with the thougth of creating my own packages but it seemed to be very complicated (reading the Debian Standard Howto). Lately I discovered, that the Debian Howto covers a lot more than I actually needed and to create a simple binary package you actually need almost only your scripts. So let’s start.