RPM: how to get changelog from package

Often there’s a need to get changelog of RPM package. Here is a way to do that: [root@playground ~]# rpm -qp –changelog kernel-2.6.41.9-1.fc15.x86_64.rpm | head * Fri Jan 13 2012 Josh Boyer <jwboyer@redhat.com> 2.6.41.9-1 – Linux 3.1.9 – CVE-2012-0045 kvm: syscall instruction induced guest panic (rhbz 773392) * Wed Jan 11 2012 Josh Boyer <jwboyer@redhat.com>…
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Bind: how to get statistics information

To get statistics information about query numbers that Bind has served you need to add next line to configuration file: statistics-file “/var/stats/named.stats”; It should be added in a ‘global’ options statement. After that you need to restart Bind and run: rndc stats Bind will dump statistics to this file. Note that if you run Bind…
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munin: fixing ‘Can’t locate object method “new” via package “LWP::UserAgent” ‘

If you get next message Can’t locate object method “new” via package “LWP::UserAgent” at /usr/share/munin/plugins/nginx_request line 106. when you are installing nginx plugins for munin in Debian, this means that you don’t have perl LWP library. Installing it fixes an issue: apt-get install liblwp-useragent-determined-perl After munin-mode restart munin will start to create graphs.

Migrating Nagios from Apache to Nginx

Nagios is powerful monitoring software. And like OTRS in most cases it’s used with Apache. But sometimes you might want to use it with nginx. Here is a simple way to do that. Actually it’s very similar to launching OTRS with nginx – in both ways we use Perl FastCGI wrapper. I assume that you…
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Trac: fixing ‘Warning: Can’t synchronize with repository “(default)” (Unsupported version control system “svn”: No module named svn).’

If you get a message ‘Warning: Can’t synchronize with repository “(default)” (Unsupported version control system “svn”: No module named svn). Look in the Trac log for more information’ while setting up or migrating you Trac, it means that you don’t have SVN library for Python installed. Note that Trac uses subversion-python package and not pysvn….
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Migrating OTRS from Apache to Nginx

Installing OTRS on Fedora is quite easy considering it has pre-built RPM packages and clean documentation. Usually OTRS is used with Apache. It’s stable well-tested solution. But what to do if you have nginx and you don’t want to have Apache? An issue becomes more complicated considering that nginx doesn’t support CGI from a box,…
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MySQL: chained replication M1>S1>S2

In most case simple master-slave replication provides enough level of high-avalability (about 99.9%), read ops balancing and allows non-blocking backups (if you use MyISAM tables since InnoDB tables can be backed up without blocking). But sometimes you may want to setup chained replication with two slaves: first slave replicates from the master, and the second…
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