The Misadventures of Penoi

To insert characters on the beginning of a line. Example, insert // from line 1 to 10

 :1,10s!^!//! 

Sample in creating folding in vim. Insert #{{{ text here #}}} provided everything was properly setup on vimrc

~/workspace/puppetworks $ cat site.pp
node 'chrisp.lab.local' {#{{{




}#}}}

pressing zc will close the folded texts

+--  6 lines: node 'chrisp.lab.local' {#----------------------------------------------------------------------------

ref: http://www.linux.com/learn/tutorials/442438-vim-tips-folding-fun

Under /etc/rsyslog.conf append

$FileCreateMode 0655
$DirCreateMode 0755
$Umask 0022

$template default,"/srv/logs/%HOSTNAME%/%$now%.log"
*.* ?default

this will create directories under /srv/logs//*.logs with Directory permission of 755 and file permission of 655

Vmware apologizes for technical difficulties on the recent webcast Technology Day Online. It looks like the webcast provider was caught off guard on the situation. To compensate, VMware will be sending me a USB memory stick containing all of the materials presented on the said event.

Well.. apology accepted!!!!! :)

Our Samsung LCD TV retired after exactly 3 yrs of service. Bad thing is that it is already out of warranty. Yesterday the screen suddenly turns to white that you can barely see the images.

Find and replace string recursively

find /home/penoycentral/whichfolder -type f -print0| xargs -0 sed -i 's/oldstring/newstring/g'

If you want to make sure that you are changing which, use the old grep first

find /home/penoycentral/whichfolder -type f -print0| xargs -0 grep -i oldstring

Example Problem: Change /etc/bind to /var/named/master in named.conf

Just print what will be changed

 sed -n 's/\/etc\/bind/\/var\/named\/master/p' named.conf 

to change:

 sed -i 's/\/etc\/bind/\/var\/named\/masterr/g' named.conf 

Change double qoute to single qoute

sed -i "s/[\"]/\'/g" some-file.pp

Referrence:
http://stackoverflow.com/questions/1583219/awk-sed-how-to-do-a-recursive-find-replace-of-a-string

DNS change progation is one of sysads problem. After a dns record change, nslookup result will differ depending on which region you are in.

Check your DNS global progation

 http://www.whatsmydns.net/

Note this setup is unsecured and just for the purpose of having my own lab svn repo.

Install mercurial on your server

yum install mercurial

Setup the mercurial site on apache

mkdir /var/www/cgi-hg
cp /usr/share/doc/mercurial-1.4/hgwebdir.cgi /var/www/cgi-hg/
chmod +x /var/www/cgi-hg/hgwebdir.cgi

Create the hgweb.config

 /var/www/cgi-hg/hgweb.config
[paths]
#VIRTUAL_PATH = /REAL/PATH
#myproject = myproject
lab = /srv/hg

Reload apache

service httpd reload

Make sure everything has the right permission on selinux or you can temporarily disable selinux

Your site now is accessible thru http://servername/hg

To test push functionality,you might try to disable ssl and allow push to all

/srv/hg/.hg/hgrc

[web]
allow_push = *
push_ssl = false

Ref:
http://mercurial.selenic.com/wiki/RHEL4HgWebDirSetup
http://mercurial.selenic.com/wiki/PublishingRepositories

Devops Singapore Meetup Puppet in production session

eth0 - with internet connection as they say
eth2 - local network

echo 1 > /proc/sys/net/ipv4/ip_forward 
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -A FORWARD -i eth2 -j ACCEPT

penoy@fedora:~$ mail -s "test sending mail from nix server" penoy@example.com < /dev/null

sysctl net.ipv4.ip_forward=1
iptables -t nat -A PREROUTING -p tcp --dport 3129 -j DNAT --to-destination ip-address:3128
iptables -t nat -A POSTROUTING -j MASQUERADE
iptables -L
iptables -t nat -L -n -v
iptables-save

Here's an example of a simple manifest file that will install a package (ex. apache) and will ensure that that the service was started after install

package {'httpd':
   ensure => installed,
    source => '/var/tmp/httpd-2.2.3-53.el5.centos.i386.rpm',
}

service {'httpd':
   ensure     => running,
   enable     => true,
   hasstatus  => true,
   hasrestart => true,
}

Seems legit. Let's apply the manifest

[root@learn tmp]# puppet apply httpd.install.pp
err: /Stage[main]//Service[httpd]/ensure: change from stopped to running failed: Could not start Service[httpd]: Execution of '/sbin/service httpd start' returned 1:  at /var/tmp/httpd.install.pp:11
notice: /Stage[main]//Package[httpd]/ensure: created
notice: Finished catalog run in 31.04 seconds

hmmm.. it seems that puppet was starting the service before the install. Let's modify the file

package { 'httpd':
ensure => installed,
source => '/var/tmp/httpd-2.2.3-53.el5.centos.i386.rpm',
}

service { 'httpd':
require => Package['httpd'],
ensure => running,
enable => true,
hasstatus => true,
hasrestart => true,
}

Now let's apply the new manifest file

[root@learn tmp]# puppet apply httpd.install.pp
notice: /Stage[main]//Package[httpd]/ensure: created
notice: /Stage[main]//Service[httpd]/ensure: ensure changed 'stopped' to 'running'
notice: Finished catalog run in 34.10 seconds

[root@learn tmp]# chkconfig --list |grep httpd
httpd           0:off   1:off   2:on    3:on    4:on    5:on    6:off
pe-httpd        0:off   1:off   2:on    3:on    4:on    5:on    6:off

[root@learn tmp]# rpm -qa |grep httpd
pe-httpd-2.2.3-17.pe.el5
pe-httpd-passenger-2.2.11-11.pe.el5
httpd-2.2.3-63.el5.centos.1
[root@learn tmp]# service httpd status
httpd (pid  15355) is running...

Disclaimer: im still a puppetlabs newbie. :)

This is one way of changing your server timezone and resync on the ntp server

 service ntpd stop

 cp /usr/share/zoneinfo/Asia/Singapore /etc/localtime

 ntpdate 

 service ntpd start 

more info: http://www.redhat.com/advice/tips/timezone.html

Normally after a server rebuild you will receive a warning that the host identification has changed

 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.

One solution is to remove the offending host key

ssh-keygen -f "/home/chris/.ssh/known_hosts" -R ip-address-of-the-host

My mysql database crashed after saving a snapshot thru KVM. Restarting mysqld shows errors under /var/log/mysqld.log

..check that your my.cnf matches the ibdata files..

one solution was to move all ib* data and restart mysqld

 mkdir /srv/mysql/old
mv /srv/mysql/ib* /srv/mysql/old
service mysqld restart

To install with prompt

virt-install --prompt

List virtual machine

virsh list

Stop virtual machine

virsh destroy 

Configure VM autostart

virsh autostart 

Unconfigure VM autostart

virsh autostart --disable 

To install using kickstart

virt-install --name=rhel03.localdomain -r 768 --disk path=/var/lib/libvirt/images/rhel03.localdomain.img,size=8 -l http://192.168.122.1/pub/inst -x "ks=http://192.168.122.1/pub/ks/rhel03.cfg"

To create VM snapshot

virsh save centos01 centos01.snap.$(date +%y%m%d)

To restore VM snapshot

virsh shutdown centos01
virsh restore centos01.snap

Clone vm

virt-clone --original centos01 --name centos02 --file /home/penoycentral/images/centos02.img

Troubleshooting KVM

Error when starting the VM snapshot

error restoring domain unable to read from monitor

To fix

virsh managedsave-remove domain-name

Set mysql root password

mysqladmin -u root password 'new-password'

Show databases

mysql> show databases;
mysql> use databasename;

Show tables

mysql> show tables;

Show columns

mysql> select column from tables;

Backup database

$mysqldump -u  -p  > backupdatabase.sql

Restore database

mysql -u  -p  < databasebackup.sql

Im a big fan of Michael Jang. Having seen this upcoming book will greatly help all RHCSA/RHCE aspirants. Hopefully Michael can give me a free copy :)

http://www.amazon.com/RHCSA-Certification-Practice-Virtual-Machines/dp/007180160X/ref=sr_1_4?s=books&ie=UTF8&qid=1335154380&sr=1-4

where is vmnetcfg in VMware Player running in Fedora 16?

It is found under:

/usr/lib/vmware/bin/vmware-netcfg

I will be sitting for Netapp Accelerated NCDA bootcamp Ontap 8.0.7-Mode next week. It will be delivered by Fastlane Singapore, one of the authorized Netapp learning Centers. Hopefully this vendor training will help me to fastrack since my company deploys Netapp storage solutions to our clients.

Will post some reviews next week (if again i have the time :) )