David Hrbáč

Centos 6 public key authentication fix

David Hrbáč — Sat, 12 May 2012 21:18:05 +0000

Due to SELinux enabled we are not able to use public key authentication on Centos 6. Here is the quick fix:

test -x /sbin/restorecon && /sbin/restorecon .ssh .ssh/authorized_keys

Generating passwords with /dev/random

David Hrbáč — Tue, 24 Apr 2012 18:28:20 +0000

One-liner to generate passwords, lock files, etc.

watch -n5 'cat /dev/urandom | tr -dc [:alnum:] | head -c12; echo'

PowerCli to add vlan to vmware cluster

David Hrbáč — Thu, 19 Apr 2012 11:12:29 +0000

Oneliner to add vlans to the all hosts within vSphere cluster:

Get-Cluster "CIT Cluster" | Get-VMHost | Get-VirtualSwitch -name vSwitch0 | New-VirtualPortGroup -name "Networking - Vlan80" -VLanId 80

Create ESXi 4.0 USB stick with dd on Linux

David Hrbáč — Sun, 15 Apr 2012 12:20:43 +0000

These are the steps to create ESX 4.0 USB stick:

mount -o loop VMware-VMvisor-Installer-4.0.0.update04-504850.x86_64.iso /mnt/
cp /mnt/image.tgz .
tar xvzf image.tgz 
bunzip2 usr/lib/vmware/installer/VMware-VMvisor-big-4.0.0-504850-x86_64.dd.bz2
dd if=usr/lib/vmware/installer/VMware-VMvisor-big-4.0.0-504850-x86_64.dd of=/dev/sdb
rm -r usr
umount /mnt

Create ESXi 4.1 USB stick with dd on Linux

David Hrbáč — Sun, 15 Apr 2012 10:18:26 +0000

These are the steps to create ESX 4.1 USB stick:

mount -o loop VMware-VMvisor-Installer-4.1.0.update02-502767.x86_64.iso /mnt/
cp /mnt/imagedd.bz2 .
bunzip2 imagedd.bz2 
dd if=imagedd of=/dev/sdb
rm imagedd
umount /mnt

Sed oneliner to change Centos 4 repos to vault.centos.org

David Hrbáč — Thu, 05 Apr 2012 15:13:07 +0000

Centos 4 is now EOLed. You should upgrade or remove your 4.x server from production. Since EOL all repositories have been moved to vault.centos.org. Yum is not working any more because of that. Here is my quick and dirty solution.

sed "s/\/mirror\.centos\.org\/centos/\/vault\.centos\.org/g;\
s/^#baseurl/baseurl/g;\
s/^mirrorlist/#mirrorlist/g;\
s/\$releasever/4\.9/g" /etc/yum.repos.d/CentOS-Base.repo -i.bak
sed "s/\/mirror\.centos\.org\/centos/\/vault\.centos\.org/g;\
s/^#baseurl/baseurl/g;\
s/^mirrorlist/#mirrorlist/g;\
s/\$releasever/4\.9/g" /etc/yum.repos.d/CentOS-fasttrack.repo -i.bak

fdupes to remove duplicate files on Linux

David Hrbáč — Thu, 29 Mar 2012 14:12:45 +0000

Quick and dirty solution to remove all duplicate files but one:

yes 1 | fdupes -rd /path/to/folder

dovecot-0.99.11-9.EL4 – assertion failed

David Hrbáč — Wed, 15 Feb 2012 11:20:03 +0000

A few days back I’m getting this error within /var/log/maillog:

file lib.c: line 37 (nearest_power): assertion failed: (num <= ((size_t)1 << (BITS_IN_SIZE_T-1)))

We are using the latest dovecot package for EL4:

[root@hruska tmp]# rpm -q dovecot
dovecot-0.99.11-10.EL4

Package changelog has interesting entry:

[root@hruska ~]# rpm -q --changelog dovecot| head
* Tue Aug 09 2011 Michal Hlavinka <mhlavink@redhat.com> - 0.99.11-10
 
- fix potential crash when parsing header names that contain NUL characters (#728674)

So, let's go fetch the #728674 entry on https://bugzilla.redhat.com/show_bug.cgi?id=728674. Oops, the page reads "You are not authorized to access bug #728674."
Good. So, Google has this: http://www.somerandomstuff.com/2011/09/30/dovecot-crash/ Well, no way to search 1TB of emails for unknown email...

This is my resolution:

[root@hruska tmp]# wget http://merlin.fit.vutbr.cz/mirrors/centos/4/os/i386/CentOS/RPMS/dovecot-0.99.11-9.EL4.i386.rpm
[root@hruska tmp]# rpm -Uhv dovecot-0.99.11-9.EL4.i386.rpm --oldpackage

Everything's ok now.

Firefox and Thunderbird repositories for Ubuntu 10.10

David Hrbáč — Tue, 17 Jan 2012 21:43:41 +0000

sudo add-apt-repository ppa:mozillateam/firefox-stable sudo add-apt-repository ppa:mozillateam/thunderbird-stable

Add line to the top of files with sed

David Hrbáč — Tue, 25 Oct 2011 15:20:21 +0000

One-liner to add line at the beginning of the file(s).

find mirrors-* -exec sed -i 1i'http://webmel53.vsb.cz/hrb33/el$releasever/hrb/stable/$basearch/' {} \;