Author: Joris Visscher

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Why no SSL!? Port is open!

Okay, this has taken me too long to not post.. So here it is..:
When your firewall is blocking SSL traffic but allowing HTTP traffic, openssl s_client will show this:

my_host:joris [/etc/stores] openssl s_client -host external_host -port 12345
CONNECTED(00000003)
write:errno=104
---
no peer certificate available
---
No client certificate CA names sent
---
SSL handshake has read 0 bytes and written 247 bytes
---
New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
---

Continue reading “Why no SSL!? Port is open!”

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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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Dell XPS 13 Skylake 9350 does not boot Fedora with UEFI while livecd works

I’ve been struggling to get Fedora working on my new laptop (Dell XPS 13 Skylake 9350) since I got it a couple of months ago. It was quite frustrating to have a working LiveCD (LiveUSB) but my laptop kept failing to boot Fedora.
Today I’ve found the problem and the fix was easy.
After the installation the EFI boot partition contains a fedora directory
( /boot/efi/EFI/fedora )
Contents of the fedora directory:
[code]
fedora
├── BOOT.CSV
├── fonts
│   └── unicode.pf2
├── fw
├── fwupx64.efi
├── gcdx64.efi
├── grub.cfg
├── grubenv
├── grubx64.efi
├── MokManager.efi
├── shim.efi <<<< This is the one!!
└── shim-fedora.efi
[/code]
The solution was to create a new Boot entry in the BIOS, this wasn’t done automatically by Fedora.
Configure the UEFI boot manager to point to the shim.efi file.
When that’s done, reboot your laptop and start using Fedora.

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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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Remove duplicate lines while comparing two files

I’ve been quite busy this whole day with a partially complete database dump and wanted to prepare for tomorrow with some ninja bash voodoo shizzle. I’m doing a braindump here because I know I’ll have forgotten this when I wake up tomorrow 🙂
The command stated below was the first working example I’ve gotten together, please let me know if you know a neater / better solution!

The situation:

I’ve got two files. The first file contains lines which need to be deleted from the second line (if they exist there) Continue reading “Remove duplicate lines while comparing two files”

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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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