25 October, 2014

Loadbalancing of PostgreSQL databases using pgpool-II and repmgr


I have to solve the PostgreSQL HA and Redundancy few weeks ago. It has been written a lot about this topic, but I was not able to find some guide describing pgpool-II and repmgr. After reading some documents I build the solution which I'm going to describe.

In short it contains the Master/Slave DB Streaming replication and pgpool load distribution and HA. The replication "part" is managed by repmgr.

Here is the network diagram:


27 September, 2014

VMware vCenter Server 5.x Appliance instalation and configuration using ssh command line

Here you can find some notes about installing VMware vCenter Appliance from command line directly form ESXi using OVF Tool.

03 September, 2014

Cacti 0.8.8b non-interactive installation and configuration

It may happen, you need to install Cacti without any user interaction. Usually after you install Cacti you need to finish the installation using Web installation wizard where you need to specify some details.

I would like to share the details how to install the Cacti 0.8.8b the automated way without user interaction.


16 June, 2014

Systemd Cheatsheet

Recently I started to use the new init system called systemd. I decided to write a simple "pdf" cheatsheet which helps me to print it and learn it.

See the (svg) example:



Here is the PDF: systemd_cheatsheet.pdf
Here is the SVG: systemd_cheatsheet.svg
Here is the DVI: systemd_cheatsheet.dvi
Here is the TeX: systemd_cheatsheet.tex

All source files can be found here: GitHub - systemd_cheatsheet

I used the following sources: Arch Linux Wiki - systemd, SysVinit_to_Systemd_Cheatsheet, RHEL7 - System_Administrators_Guide.

Enjoy ;-)

08 May, 2014

Turris - OpenWRT and guest access

In my previous blog post I described the way how to configure the Turris router for my home network. I decided to extend the configuration and create the Guest WiFi for other people who want's to access the "Internet". In my solution I'm using the nodogsplash captive portal solution which offers simple way to provide restricted access to an Internet connection. Here is the extended network diagram:


22 April, 2014

Turris - OpenWRT and thermometers


I would like to put here some notes about the thermometers in OpenWrt and Turris.

Turris internal thermometers

Turris has it's own thermometers which are monitoring the temperature of CPU and board. The how-to expects the previous lighttpd configuration described in my previous post. Here is the way how you can create graps wrom the data using RRDtool.

16 April, 2014

Turris - OpenWrt configuration

You can find out some details about Turris wifi router, lot of photos and some command outputs in my previous blog post. Now I would like to describe the way how I configured it according the network diagram:



I will also need my own web pages, transmission torrent client, microsd card, Dynamic DNS and extend the luci interface to add some more stats + graphs. Here are the steps how I did it. There is no guarantee it will work for another Turris router.

09 April, 2014

Turris - The Open Enterprise Wi-Fi Router

Few months ago I joined the Turris project (turris.cz) which is a not-for-profit research project of CZ.NIC. I don't want to describe the details of the project, because you can find it on it's web page. In short the company standing behind the project take care about the Internet security and their idea was to measure number of attacks / suspicious traffic by giving the wifi routers to the participants.
The wifi router was designed by the company and it's quite powerfull machine costs 600$. In the first "round" some project members got the wifi router for free so I would like to share here the details bout it, because it's open hardware/software platform.

31 December, 2013

Upgrade firmware in HP servers using HP Service Pack for ProLiant and Cobbler

I you have to upgrade the firmware (iLO, BIOS, Disk firmware, NIC firmware, ...) inside many HP servers and for this task it's useful to use HP Service Pack for ProLiant (HP SPP).

This iso file contains the firmware for all supported HP servers. The easiest way is to boot from the ISO file and upgrade the server where it is running. If you have many servers - it's better to use automated way using PXEboot + Cobbler + NFS.

I would like to share few steps how I did it in my environment.

27 November, 2013

Server RAID/BIOS changes using HP Scripting toolkit and Cobbler

I have to take care about few enclosures with HP ProLiant BL685c and HP ProLiant BL460c blades (both G1). They are quite old now, but still can do a good job. Because there were no operating system I have no idea how the RAID or BIOS is configured. Obviously I want to have it configured the same and I really don't want to go through all of them one by one and configure it manually.

Lucky for me there is a HP Scripting Toolkit (or HP SmartStart Scripting Toolkit) which can boot over PXE and get/set the BIOS/RAID configuration.
It is handy if especially if you have a new servers without OS installed.

Let's see how you can install and configure Cobbler, NFS, PXE, tftpboot and HP Scripting Toolkit to modify the BIOS/RAID information on the server.

11 November, 2013

Automated installation of Windows 7 in KVM


Sometimes I need to test/work with Windows 7 in my libvirt/KVM virtualization. Because the testing can be destructive I decided to automate it as much as possible. As a linux user there is not much options to modify ISO image and create fully unattended installation, because I need the "windows only" tools for that. I also don't want to use unattended configs shared by SAMBA, because it looks too complex for one VM.

Anyway here is the description of solution how I'm "fighting" with the automated Windows installation in the Virtual Machine manager.

23 August, 2013

How to get HP enclosure c7000 information without ssh


In past wef days I was doing some scripting to get the details bout the HP BladeSystem c7000
You can do a lot though the SSH access, but I prefer to get the data without setting up ssh keys or doing some expect scripts. I neede "showAll" output and some nice structured XML file containing the hardware description, MACs, WWIDs, etc...

Maybe it can be useful for some people who wants to do the same - here is the example:



Here is the external link:
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=c02843807

Enjoy :-)

03 August, 2013

TP-Link TL-WR1043ND and OpenWrt 12.09 with two SSIDs (MultiSSID) - private and guest

I decided to change my home network to match the following "network diagram":



The core part of the design is TP-Link TL-WR1043ND wifi router running OpenWrt with small 16GB USB stick [/dev/sda1] containing ext3 partition with OpenWrt configuration + swap.

There are also 16GB USB stick and 2 thermometers connected using USB <-> Serial connector (bought on eBay):

I'm going to use the last stable version of the OpenWrt firmware: openwrt-ar71xx-generic-tl-wr1043nd-v1-squashfs-sysupgrade.bin

Upgrade the firmware and remove the old configuration:
rm -r /tmp/opkg-lists/
sysctl -w vm.drop_caches=1
sysupgrade -v -n http://downloads.openwrt.org/attitude_adjustment/12.09/ar71xx/generic/openwrt-ar71xx-generic-tl-wr1043nd-v1-squashfs-sysupgrade.bin

Here are the notes how way how I configured it.

If you don't like the commands feel free to check the configs here: https://github.com/ruzickap/linux.xvx.cz/tree/gh-pages/files/openwrt

24 June, 2013

TL-WR1043ND wifi router with camera and theromometers


Here are few photos of my 2 old year TP-Link TL-WR1043ND wifi router. It was getting some pictures from camera using fswebcam and measure internal/external temperature using digitemp.


All that time if was running:

BusyBox v1.15.3 (2011-04-30 19:48:15 CEST) built-in shell (ash)
Enter 'help' for a list of built-in commands.

  _______                     ________        __
 |       |.-----.-----.-----.|  |  |  |.----.|  |_
 |   -   ||  _  |  -__|     ||  |  |  ||   _||   _|
 |_______||   __|_____|__|__||________||__|  |____|
          |__| W I R E L E S S   F R E E D O M
 Backfire (10.03, r23915) --------------------------
  * 1/3 shot Kahlua    In a shot glass, layer Kahlua 
  * 1/3 shot Bailey's  on the bottom, then Bailey's, 
  * 1/3 shot Vodka     then Vodka.
 ---------------------------------------------------
And now it's waiting for the latest stable Openwrt release...

28 January, 2012

Another OpenWrt configuration

I would like to describe another OpenWrt configuration. It's going to be just few examples how to configure latest available OpenWrt firmware Backfire 10.03.1.

I'm going to use TP-Link TL-WR1043ND wifi router with small 64MB USB stick [/dev/sda1] containing ext2 partition. I plan to have some stats on the USB stick and simple html pages as well.