02/07/2016

Psi Probe error

If you work with j2ee application you need Tomcat and not some stupid gigantic enterprise application server, and if you work with Tomcat you really need Psi Probe because it’s the best Tomcat manager you can find all over the galaxy.

Recently I noticed a strange behavior from this tool after some activities focused on security hardening.
I had some old Tomcat 6 instances where I want to get rid of Tomcat version inside error pages and inside http headers, after I removed these data Psi Probe went crazy with a nasty exception “java.lang.RuntimeException: No container found for your server” :\

error

After some googling I found that Psi Probe uses ServerInfo to determine the Tomcat version, I completely erased this information for security issues so the poor Psi Probe lost its mind…

The solution is quite simple, open the probe.war archive (you can unzip it) and change the WEB-INF/spring-probe-resources.xml file this way:

  1. find “forceFirstAdaptor” variable inside the “com.googlecode.psiprobe.beans.ContainerWrapperBean” and change it’s value from false to true
  2. change the list inside the “adaptorClasses” property putting as first record the value referring to your Tomcat version (in my case “<value>com.googlecode.psiprobe.Tomcat60ContainerAdaptor</value>”)

spring-probe-resources

After that you only have to repackage the files and deploy the war.

17/06/2016

nmon-script

Nmon is wonderful, if you need to monitor you server resources in realtime it’s your tool, if you need to monitor resources statistics over time and save them it’s your tool, if you need to check what’s the status of your server’s resources in a precise moment it’s your tool.
I can’t imagine a scenario where you don’t need nmon, more useful and flexible than sar, simpler and more straightforward than any other web based tool, imho it’s the perfect companion for collectd.

Sadly during on my last server setup I noticed that the latest nmon package distributed by Epel repository lacks of all the cron scripts you need to automate nmon startup and data collection, which imho are very useful also if you get nmon directly from the official GNU/Linux project site.

Here’s some hints from the old packages, first of all create the /var/log/nmon directory with nobody user as owner.

nmon01

Create a new script in cron for example /etc/cron.d/nmon-script.
This cron will launch /usr/bin/nmon-script every day (for example at midnight).

nmon02

Now you have to create the /usr/bin/nmon-script file (remember to give execution permission) which has:

  • some configuration parameters in /etc/sysconfig/nmon-script
  • commands to kill, cleanup old files (disabled in the example, note the leading # at line 15)

nmon03

Create the /etc/sysconfig/nmon-script which contains some useful varibles (the directory where to save nmon archive files, retention and nmon options).

nmon04

That’s enough, at the next midnight nmon will start to save your resources statistics in /var/log/nmon/<hostname>_AAMMDD_0000.nmon files.

nmon05

You can download all the scripts and files to quickly setup the nmon-script:
nmon-script.tar.gz (656B)
SHA256 hash: 953667d8e2806e4858426fb000d7f3cfc898c53e26ffc7694bf2722442668aa8

[EDIT]

Nmon is not distributed by Epel but from RPMForge!!
Although RPMForge version is quite old it has nmon-script cron, I suggest to move to the latest version from the official GNU/Linux project site which do not have nmon-script.

18/04/2016

A quick update

Well, time has passed since the last update on this blog, it’s time to do a quick recap on some of my new year’s goals.

First of all I archived one of the most important and desired goals: swimming!
During these first 3 and a half months I went swimming almost two times a week, sometimes three, starting with 20 pools at low pace and raising up to the actual 40 pools in 40-45′; as I expected each time I go swimming I feel better and better, actually it’s the only thing makes me feel really good and the only weapon I have against my terrible working stress…

nuoto1

Talking about work I can’t deny we have huge emergencies during the last month, as I predicted (I repeat the same thing for years…) we had great problems on our biggest customer with some stupid custom applications deployed on a huge WebSphere Portal cluster.
Remember the KISS model? My company did the exact opposite, this application produced huge out of memory problems on the Portal jvm, I sent logs and begged developers to fix the huge amount of exceptions we collected but nothing changed  since the problem went really crytical; at the end they fixed the exceptions and made changes to the code and all returned to work normally.

Remember: if you are working on some big enterprise software meatball like WebSphere Portal DO NOT deploy custom applications on that product unless you are ABSOLUTELY sure of their quality!
Use some easy Tomcat or Jboss instance, hundreds of them if you need to scale out for a big workload, you will live better, spent an infinitesimal part of money and will get a better result.

And what about Eve?
Well I finally get a second account, I used the buddy program and made a brand new cyno/scout alt and I’m skilling for the biggest and most ambitious project since I started play: two jumpfreighter pilots!
Yes, it’s not a typo, I need two JF pilots for take my future Rhea in null space and also in hi-sec, so I need a second JF pilot in npc corp to fly safe and now lose this huge ship in some stupid war brawl…
Look at that beauty, isn’t it gorgeous?

Rhea4

30/01/2016

Vmware ESXi Embedded Host Client

I know there are many good hypervisors, some of them are free and are full of advanced features (someone say oVirt?) but if you want to work into virtualization you can’t ignore Vmware.

Don’t get me wrong, I like Vmware products and I use them every day on servers, on my lab workstation and also on my old duty laptop, but sometimes customers tend to be too much conservative and sticked to it.
For example I found many people who prefer to use free Vmware ESXi (without vcenter, vmotion or svmotion) insted other solutions (free or low cost) with all the advanced features that any server hypervisor must have.

One of the most evident limitations of the free ESXi is the client which require a Windows OS, fortunately there’s a wonderful free solution for that: ESXi Embedded Host Client.

The installation is really easy, first of all you must download the installation package (esxui_signed.vib) from the official site and copy on the ESXi host (you can use the datastore browser or copy via scp).
After that you must access ESXi using ssh protocol, and launch “esxcli software vib install” command

esxi01

That’s all, now you can open your browser to url https://youresxiserver/ui and…

esxi02

What?!?!?
Keep calm, if you’re using ESXi 5.5 prior to update 2 there are some known issues, this is one of them.
To solve it we must edit  /etc/vmware/rhttpproxy/endpoints.conf, but the file is locked (operation not permitted error), so we must copy it to a temporary location (for example /tmp), edit it and copy on the original path again.

esxi03

The only change you must to is to comment the line starting with /ui putting a # at the beginning (force write on exit with :x! vi command)

esxi04

Now copy the edited file into its original path with “cp /tmp/endpoints.conf /etc/vmware/rhttpproxy/endpoints.conf” and restart rhttpproxy daemon with “/etc/init.d/rhttpproxy restart”

esxi05

Now try to browse https://youresxiserver/ui/ url (don’t forget the trailing /, another bug in ESXi 5.5U2 and earlier versions) and…

esxi06

esxi07

Mission accomplished!

11/01/2016

Compress logs by date

Sometimes it happens to find a service which rotates logs but don’t rename them using an easy date format (for example logYYYYMMDD.log), that’s horrible if you have to archive those logs :\

Here is a simple bash script I use to compress them based file modification date, check comments for adapt it to your log names.

download: logmonth_1.0.sh
md5sum: 4b587eb3c2d9ac413d81a0bdc055c6cf

 

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