May 05 2016

MariaDB(MySQL) Master-Master Replication

MariaDB_Master-Master_Replication

I’m going to develop my cluster further and create MariaDB(MySQL) geo-cluster by enabling MariaDB(MySQL) Master-Master Replication. I’ve already deployed MariaDB cluster in the second datacenter (nodes 4, 5 and 6) and now I need to configure Master-Master replication between two MariaDB clusters. The replication will take place between node 1 (first datacenter, we will name it Master1) and node 4 (second datacenter, we will name it Master2).

First of all we need to check a couple of variables that may impact or break replication.  Continue reading

Apr 22 2016

MariaDB Galera three nodes cluster on CentOS 6

mariadb-galera-cluster-centos-6

Let’s build MariaDB Galera cluster with three nodes on CentOS x64 6.7 Minimal.
On all nodes static IP adresses have been configured.
Node1- 10.20.20.11
Node2 – 10.20.20.12
Node3 – 10.20.20.13

On all nodes we need to install necessary packages: Continue reading

Apr 15 2016

Cloned Hyper-V CentOS6 Server error “device eth0 does not seem to be present, delaying initialization”

In order to have 3 identical nodes for my MariaDB Galera cluster, I cloned a hyper-v install of CentOS6 and after firing up the clone and trying to start networking received the error: “device eth0 does not seem to be present, delaying initialization”

We need to get the list of current eth devices:

Continue reading

Apr 14 2016

Failed to sync data for Routing group {8EC325CB-B512-587D-9D03-E940E7CC1490} from backup store

After a fresh deployment of Skype for Business Server 2015  on a Windows Server 2012  the Lync Server Front-End service fails to start:

image

Reviewing the Skype for Business Server 2015 event logs show the following events: Continue reading

Apr 14 2016

Lync Server 2013 Event ID 14649 Error 0x800B0109(CERT_E_UNTRUSTEDROOT)

After the December update Windows Server 2012 no longer trust the certificate that is trusted before. Certificate from RapidSSL is fully in order. In Lync Deployment Wizard certificate is also displayed correctly and without errors. First stop service Lync Server Access Edge was recorded on December 18. Immediately after applying the latest updates for Windows Server 2012 .:) Continue reading

Mar 24 2016

Colorize log files on CentOS and Ubuntu using ccze tool

ccze

ccze is a wonderful tool that brings real joy to the arduous task of reading or searching thru log files. It uses a modular approach to support custom colour formatting for popular applications such as Apache, Postfix, Exim, etc. Continue reading

Mar 23 2016

How to install and use vnstat (Network Traffic Monitor) in Linux

vnStat is a console-based network traffic monitor for Linux and BSD that keeps a log of network traffic for the selected interface(s). It uses the network interface statistics provided by the kernel as information source. This means that vnStat won’t actually be sniffing any traffic and also ensures light use of system resources.
In this article we will show you how to install and use vnStat (Network Traffic Monitor) on RHEL/CentOS linux distribution. Continue reading

Mar 18 2016

SSL/TLS Alert Protocol & the Alert Codes

There have been many occasions where a event corresponding to SChannel is logged in the System event logs which indicates a problem with the SSL/TLS handshake and many a times depicts a number. The logging mechanism is a part of the SSL/TLS Alert Protocol.
SChannel logging may have to be enabled on the windows machines to get detailed SChannel messages. Please refer the following article to do so: http://support.microsoft.com/kb/260729

These warnings sometimes are very helpful in troubleshooting SSL related issues and provide important clues. However, there is not much documentation available on the description of the alert codes. Continue reading

Mar 16 2016

Reset administrator password in Drupal

When in Drupal 8, the password for user #1 (the administrator) is lost and the email notification don’t work, it is possible to set the password via a database query.

You’ll need access to your hosting server’s shell and database in order to reset administrator’s password in Drupal. Continue reading

Feb 26 2016

Asterisk installation on CentOS with YUM

Asterisk PBX

Officially now Asterisk packages repository is gone (but packages are still on place). Asterisk installation manual gone as well. This post is some handy memo on Asterisk install from packages using YUM. Continue reading

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