Category: Tips

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Exclude grep itself from ps

This is so simple it’s just great 🙂
Solution: use regex in your grep so the grep itself doesn’t show up in the results.
Example:

[vagrant@london kafka]$ ps aux |grep kafka
vagrant 5172 0.8 30.3 3178252 309428 ? Sl 07:00 0:06 java -Xmx1G -Xms1G -server -XX:+UseG1GC -XX:MaxGCPauseMillis=20 -XX:InitiatingHeapOccupancyPercent=35 -XX:+DisableExplicitGC -Djava.awt.headless=true -Xloggc:/var/log/kafka/kafkaServer-gc.log -verbose:gc -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintGCTimeStamps -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dkafka.logs.dir=/var/log/kafka -Dlog4j.configuration=file:/etc/kafka/log4j.properties -cp :/usr/bin/../share/java/kafka/*:/usr/bin/../share/java/confluent-support-metrics/*:/usr/share/java/confluent-support-metrics/* io.confluent.support.metrics.SupportedKafka /vagrant/config/kafka0.properties
vagrant 5824 0.0 0.0 103316 836 pts/0 R+ 07:13 0:00 grep kafka  <<-- Oh no!
[vagrant@london kafka]$
[vagrant@london kafka]$ ps aux |grep [k]afka
root 5172 0.8 29.6 3178252 302472 ? Sl 07:00 0:04 java -Xmx1G -Xms1G -server -XX:+UseG1GC -XX:MaxGCPauseMillis=20 -XX:InitiatingHeapOccupancyPercent=35 -XX:+DisableExplicitGC -Djava.awt.headless=true -Xloggc:/var/log/kafka/kafkaServer-gc.log -verbose:gc -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintGCTimeStamps -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dkafka.logs.dir=/var/log/kafka -Dlog4j.configuration=file:/etc/kafka/log4j.properties -cp :/usr/bin/../share/java/kafka/*:/usr/bin/../share/java/confluent-support-metrics/*:/usr/share/java/confluent-support-metrics/* io.confluent.support.metrics.SupportedKafka /vagrant/config/kafka0.properties
[vagrant@london kafka]$

 
 

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Using SSH to forward the same local port to multiple external hosts

Okay, this is kinda awesome :-), I got my geek on 🙂
My application is connecting to a cluster of external servers but my application can configure hostname but can’t configure port.
So I wanted to connect to a remote cluster using SSH tunneling, but I was unable to forward everything because the port binding to localhost (127.0.0.1) can only be used once.
Then I saw that you can use multiple loopback addresses! See this page: https://en.wikipedia.org/wiki/Loopback
Basically you can bind the portforward to 127.0.0.2, 127.0.0.3 till 127.255.255.254, that should provide enough addresses, right!? 🙂
So I can use multiple port forwards from my localhost(s) to the six remote hosts like this:

ssh somedomain.com \
-L 127.0.0.1:9042:external-node1.somedomain.com:9042 \
-L 127.0.0.2:9042:external-node2.somedomain.com:9042 \
-L 127.0.0.3:9042:external-node3.somedomain.com:9042 \
-L 127.0.0.4:9042:external-node4.somedomain.com:9042 \
-L 127.0.0.5:9042:external-node5.somedomain.com:9042 \
-L 127.0.0.6:9042:external-node6.somedomain.com:9042
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Vagrant proxy through CNTLM on Windows using CYGWIN

Wow, talk about a crappy post title, but I just got this working on my corporate network and was quite happy about it.
Reason for this post; Every time I start a new assignment at a (rather big) corporation, I need to follow these steps to be able to access the internet from my vm’s.
(and I keep forgetting the steps, I’m getting old..)
What we’ll use to get this working:

  • Cygwin : https://www.cygwin.com/
  • Vagrant : https://www.vagrantup.com/
  • Virtualbox : https://www.virtualbox.org/
  • Cntlm : http://cntlm.sourceforge.net/

I’m running CentOS vm’s inside Vagrant with Virtualbox provisioning on Cygwin on Windows 7. I’m running Cntlm to create a local proxy for all stuff what I’m doing through cygwin, because I don’t like putting clear text passwords in bashrc or in Win / Bash variables.

Steps:

  1. Get your corporate proxy URL (Via Google Chrome)
  2. Configure Cntlm
  3. Configure Cygwin
  4. Configure Vagrant
  5. Use teh interwebs from your VM, practicing ninja turtle coding skillz and be instantly awesome!!1!

Continue reading “Vagrant proxy through CNTLM on Windows using CYGWIN”

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BEA-010213, Message-Driven EJB: MyProcessMDB's transaction was rolled back

I encountered this error last week and it was quite a headache to find out what the source of the problem was.

Short summary:

I thought the BEA-010213 error and the rollback log entries meant that we had a database problem. This was a wrong assumption, there’s another storage type in weblogic domains which use transactions (or state transitions?), which are JMS queues, which live in persistent stores in the managed servers.
That was the source of our problem; our persistent stores became corrupted because of storage problems.
Continue reading “BEA-010213, Message-Driven EJB: MyProcessMDB's transaction was rolled back”

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Python pip without internet

The title of this post is a bit misleading. I will not outline the use of pip without internet but I will suspect most people will search for this search string, thus coming here for an alternative.
I’ve been blessed with a very thorough security officer, who decided that CLI internet access is not permitted, even using CNTLM (1)is blocked.
The easiest way to install packages is via pip, but it’s also possible to install them via the commandline.
Using the example of Django, we will first download the tarball from the Django site;
https://www.djangoproject.com/download/
On the right side there’s a link to the latest release.
Unzip and untar the tarball and open a Prompt in that directory.
Then run the following command:
python setup.py install

Next, we’ll check if it is installed correctly:
2015-10-20 13_11_27-Opdrachtprompt

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Create a simple HTTPS server with OPENSSL S_SERVER

This post will mostly serve as a reference for future posts, the goal is to create the simplest HTTPS webserver possible, which will serve to test certificates, authentication via private keys and in the end; configure SSL offloading to an Apache HTTPD, which will act as a proxy between your client and the secure endpoint.
GOAL: At the end of this article, you will have a running secure web server which you can access via your web browser and/or via an SSL client. Continue reading “Create a simple HTTPS server with OPENSSL S_SERVER”

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Comparing sed stream output in linux

Sed is very very powerful, which is a good thing to be aware of.
I was looking to compare the output of a sed command to the original file before I wanted to execute the sed command directly on the file and came across this handy trick.
It works by using temporary named pipes inside the diff command.
Contents of file:
[code title=”contents of numbers.txt:”]
One
Two
Three
Four
Five
[/code]
If I just want to remove the line which begins with “Four”, I can check my sed command like this:
[code title=”Terminal output:”]
joris@beanie ~
$ diff <(sed ‘/Four/d’ numbers.txt) numbers.txt
3a4
> Four
[/code]
Awesome possum, now I know my sed command won’t destroy anything.

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Fedora Gnome-shell abnormal high CPU usage in combination with Intel GM 4000 videocard

I’ve been using my trustworthy thinkpad for a couple of years now, but as soon as I installed Fedora on it, it became quite slow due to gnome-shell using a huge amount of CPU power.
My thinkpad isn’t the quickest out there, it’s a dual core machine from around 2006, but 50% CPU on two cores for just Gnome was a bit excessive.
I’ve been searching a lot, and didn’t found any solution, until I started fiddling with Gnome-tweak-tool and saw the “Background logo” entry.
If you haven’t yet; Install gnome-tweak-tool with the following command:
sudo yum install gnome-tweak-tool
The background logo is an PNG overlay on your desktop, and that overlay doesn’t work well with Intel GM cards.
Start gnome-tweak-tool, disable that extention and see your CPU usage drop to 2%, which is what it should be.
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