Posts Tagged ‘java’

Old Dell iDrac – work around Java failures

Wednesday, June 5th, 2019

I have an old Dell server (R610, if it’s important) and I seem to fail to connect to its iDrac console via Java. No other options exist, and the browser calling Java flow fails somehow.

I have found an explanation here, and I will copy it for eternity 🙂

First – Download the latest JRE version 1.7 from https::/

Then, extract it to a directory of your choice. We’ll call this directory $RUN_ROOT

Download the viewer.jnlp file to this directory $RUN_ROOT, and open it with a text editor. You will see an XML block pointing at a JAR file called avctKVM.jar. Download it manually using ‘wget’ or ‘curl’ from the URL provided in the viewer.jnlp XML file.

Extract the avctKVM.jar file using ‘unzip’. You will get two libraries – avctKVMIO(.so or .dll for Windows) and avmWinLib(.so or .dll for Windows). Move these two files into a new directory under $RUN_ROOT/lib

Download/copy-paste the below .bat or .sh script files (.bat file for Windows, .sh file for Linux).


@echo off

set /P drachost="Host: "
set /p dracuser="Username: "
set "psCommand=powershell -Command "$pword = read-host 'Enter Password' -AsSecureString ; ^
    $BSTR=[System.Runtime.InteropServices.Marshal]::SecureStringToBSTR($pword); ^
for /f "usebackq delims=" %%p in (`%psCommand%`) do set dracpwd=%%p

echo -n 'Host: '
read drachost
echo -n 'Username: '
read dracuser
echo -n 'Password: '
read -s dracpwd
./jre/bin/java -cp avctKVM.jar -Djava.library.path=./lib com.avocent.idrac.kvm.Main ip=$drachost kmport=5900 vport=5900 user=$dracuser passwd=$dracpwd apcp=1 version=2 vmprivilege=true "helpurl=https://$drac

Run the downloaded script file (with Linux – you might want to give it execution permissions first), and you will be asked for your credentials.

Thanks Nicola for this brilliant solution!

Graphing on-demand Linux system performance parameters

Tuesday, May 20th, 2008

Current servers are way more powerful than we could have imagined before. With quad-core CPUs, even the simple dual-socket servers contain lots of horse-power. Remember our attitude towards CPU power five years ago, and see that we’re way beyond our needs.

When modern servers are equipped with at least eight cores, other, non-CPU related issues become noticeable. Storage, as always, remains a common bottleneck, and, as an increase in expectations always accommodate increase in abilities, memory and other elements can be the cause for performance degradation.

sar‘ is a known tool for Linux and other Unix flavors, however, understanding the contexts within is not trivial, and while the data is there, figuring what is relevant for the issue at hand becomes, with more disk devices, and more CPUs, even more complicated.

kSar is a simple java utility which makes this whole mess into a simple, readable graphs, capable of being exported to PDF for the pleasure of the customers (where applicable). It parses existing sar files, or the extracted contents of ‘sa’ files (from, by default, /var/log/sa/). It is a useful tool, and I recommend it with all my heart.

Alas, when it comes to parsing ‘sa’ files, you will need, in most cases, either to export the file into text on the source machine, or use a similar version of sysstat tools, as changes in versions reflect changes in the binary format used by sar.

You can obtain the sysstat utils from here, and compile it for your needs. You will need only ‘sar’ on your own machine.

An important note – you will not be able to compile sysstat utils using GCC 4.x. Only 3.x will do it. The error would look like:

warning: ‘packed’ attribute ignored for field of type `unsigned char…

followed by compilation errors. Using GCC version 3.x will work just fine.

Some few small insights

Wednesday, March 12th, 2008

Lately I have been overloaded above my capabilities. This did not prevent me from doing all kind of things, but most of them are too small to justify a real entry here, so I have decided to make a small collection of small stuff someone might need to know, in order to make it indexed in search engines. These small insights might save some time for someone. This is a noble cause.

1. Oreon is a nice overlay for Nagios, however, it is poorly documented, and some of the existing docs are in French. I have put hours on building it into a working setup, and I hope to be able to write down the process as is.

2. “Sun Java System Active Server Pages” does not support 64bit Linux installations – at least not if you’re interested in using it with your existing Apache server. Look here. Seems nothing has changed.

3. Under Ubuntu 7.10, Compiz suffers from a major memory leak when using NVidia display adapters. You can read about it in the bug page. I was able, thanks to this link, to workaround it using compiz –indirect-rendering . Does not see to cause any ill-effect on my display performance.

4. Suse 10 and wireless cards – This one is a great guide, which I would happily recommend.

5. Flushing the existing read buffer for your Linux machine (should never be done, unless you’re testing performance) can be done by running the following command:

echo 1 > /proc/sys/vm/drop_caches

Seems to be enough for today. Hope these tips help.