Fun with Issues/Tips - Charlie's Own Blog

Nagios - Memory Check Plugin

noreply@blogger.com (Anonymous) — Mon, 04 Jul 2016 06:53:00 +0000

Thought this might be of use to some one.

Originally sourced from Nagios Directory

Centos 7

#!/bin/bash
if [ "$1" = "-w" ] && [ "$2" -gt "0" ] && [ "$3" = "-c" ] && [ "$4" -gt "0" ]; then
FreeM=`free -m`
memTotal_m=`echo "$FreeM" |grep Mem |awk '{print $2}'`
memUsed_m=`echo "$FreeM" |grep Mem |awk '{print $3}'`
memFree_m=`echo "$FreeM" |grep Mem |awk '{print $4}'`
memBuffer_cache_m=`echo "$FreeM" |grep Mem |awk '{print $6}'`
memAvailable_m=`echo "$FreeM" |grep Mem |awk '{print $7}'`
memUsed_m=$(($memTotal_m-$memFree_m-$memBuffer_cache_m))
memUsedPrc=`echo $((($memUsed_m*100)/$memTotal_m))||cut -d. -f1`
if [ "$memUsedPrc" -ge "$4" ]; then
echo "Memory: CRITICAL Total: $memTotal_m MB - Used: $memUsed_m MB - $memUsedPrc% used!|TOTAL=$memTotal_m;;;; USED=$memUsed_m;;;; BUFFER/CACHE=$memBuffer_cache_m;;;; AVAILABLE=$memAvailable_m;;;;"
exit 2
elif [ "$memUsedPrc" -ge "$2" ]; then
echo "Memory: WARNING Total: $memTotal_m MB - Used: $memUsed_m MB - $memUsedPrc% used!|TOTAL=$memTotal_m;;;; USED=$memUsed_m;;;; BUFFER/CACHE=$memBuffer_cache_m;;;; AVAILABLE=$memAvailable_m;;;;"
exit 1
else
echo "Memory: OK Total: $memTotal_m MB - Used: $memUsed_m MB - $memUsedPrc% used|TOTAL=$memTotal_m;;;; USED=$memUsed_m;;;; BUFFER/CACHE=$memBuffer_cache_m;;;; AVAILABLE=$memAvailable_m;;;;"
exit 0
fi
else # If inputs are not as expected, print help.
sName="`echo $0|awk -F '/' '{print $NF}'`"
echo -e "\n\n\t\t### $sName Version 2.1###\n"
echo -e "# Usage:\t$sName -w -c "
echo -e "\t\t= warnlevel and critlevel is percentage value without %\n"
echo "# EXAMPLE:\t/usr/lib64/nagios/plugins/$sName -w 80 -c 90"
echo -e "\nCopyright (C) 2012 Lukasz Gogolin (lukasz.gogolin@gmail.com), improved by Nestor 2015\n\n"
exit
fi

Old Version

#!/bin/bash

if [ "$1" = "-w" ] && [ "$2" -gt "0" ] && [ "$3" = "-c" ] && [ "$4" -gt "0" ]; then

FreeM=`free -m`

memTotal_m=`echo "$FreeM" |grep Mem |awk '{print $2}'`

memUsed_m=`echo "$FreeM" |grep Mem |awk '{print $3}'`

memFree_m=`echo "$FreeM" |grep Mem |awk '{print $4}'`

memBuffer_m=`echo "$FreeM" |grep Mem |awk '{print $6}'`

memCache_m=`echo "$FreeM" |grep Mem |awk '{print $7}'`

memUsedPrc=`echo $((($memUsed_m*100)/$memTotal_m))||cut -d. -f1`

if [ "$memUsedPrc" -ge "$4" ]; then

echo "Memory: CRITICAL Total: $memTotal_m MB - Used: $memUsed_m MB - $memUsedPrc% used!|TOTAL=$memTotal_m;;;; USED=$memUsed_m;;;; CACHE=$memCache_m;;;; BUFFER=$memBuffer_m;;;;"

exit 2

elif [ "$memUsedPrc" -ge "$2" ]; then

echo "Memory: WARNING Total: $memTotal_m MB - Used: $memUsed_m MB - $memUsedPrc% used!|TOTAL=$memTotal_m;;;; USED=$memUsed_m;;;; CACHE=$memCache_m;;;; BUFFER=$memBuffer_m;;;;"

exit 1

else

echo "Memory: OK Total: $memTotal_m MB - Used: $memUsed_m MB - $memUsedPrc% used|TOTAL=$memTotal_m;;;; USED=$memUsed_m;;;; CACHE=$memCache_m;;;; BUFFER=$memBuffer_m;;;;"

exit 0

fi

else # If inputs are not as expected, print help.

sName="`echo $0|awk -F '/' '{print $NF}'`"

echo -e "\n\n\t\t### $sName Version 2.0###\n"

echo -e "# Usage:\t$sName -w <warnlevel> -c <critlevel>"

echo -e "\t\t= warnlevel and critlevel is percentage value without %\n"

echo "# EXAMPLE:\t/usr/lib64/nagios/plugins/$sName -w 80 -c 90"

echo -e "\nCopyright (C) 2012 Lukasz Gogolin (lukasz.gogolin@gmail.com), improved by Nestor 2015\n\n"

exit

fi

Managing your Samba - Active Directory

noreply@blogger.com (Anonymous) — Thu, 10 Dec 2015 06:47:00 +0000

So how do you manage the samba active directory setup? does it have a front end?

The easiest way to administer an Active Directory is by using Microsoft RSAT (Remote Server Administration Tools) on a Windows machine.

"samba-tool" already contains many features for common administration jobs, but compared with the RSAT, it is still missing many options. Another big advantage of using RSAT, it increases the available documentation (books, online, etc.), because it's the common way Windows administrators are doing these tasks.

Download and install RSAT from microsoft website and setup using - Add or remove windows programs feature from control panel.

Installation:

Install RSAT using the downloaded installer

Open "Programs and Features" (use the "Start Menu/Metro search to locate the tool).

Open "Turn Windows features on or off"

Depending on the administrative tasks you want to perform, you choose the features to install. The following are recommended options to be installed for Samba Active Directory installations:

Most of the RSAT tools hide content and menu options in their default setting. To enable all features and display the whole content in each program, go to the "View" menu and activate "Advanced Features". Typically this option is only visible, when you've marked the root of the tree view.

Ref:

1. Installing RSAT

Hope this helps :)

Setup your free Active Directory in linux :)

noreply@blogger.com (Anonymous) — Thu, 10 Dec 2015 05:55:00 +0000

Hey Guys!

So we had to decommission our Active Directory server as it was running on pretty old hardware and win 2003. With the cost factor involved we decided to give linux based domain controller a try. All my initial thoughts was to use ldap as thats what we normally refer to as AD alternative for linux, unfortunately things were not as easy as it seemed to be. we could only add linux machines or users to the ldap and the guy who manages the system ( who provisions machines and user accounts ) found it difficult to use ldap frontend.

So there started the search for something simpler and easy to manage and voila here comes SAMBA 4. Samba 4 ?? are you crazy its used for sharing files to windows machines how can you even compare it with Active Directory! its true :) I am just quoting the details from samba wiki here as its very much informative.

Things to look out for

1. DNS - super important as everything depends on how dns setup is configured. So extra care needs to be done while this is setup. Almost 90% of issues arises due to incorrect DNS setups
2. Use of static IPs instead of dhcp.

Explanations for the links shared below.

1. This one pretty much helps you setup the primary DC
2. The second link helps you to setup a failover/setup

Ref:

1. Setup a Samba Active Directory Domain Controller
2. Join an additional Samba DC to an existing Active Directory
3. Check and fix DNS entries on DC joins

Hope this helps ;)

Check out the blog for more details on how to manage the Samba DC from a windows machine like you do with Active Directory.

Python + pkg_resources.DistributionNotFound:

noreply@blogger.com (Anonymous) — Mon, 31 Aug 2015 09:11:00 +0000

This usually occurs if your python setuptools are old version. I tried upgrading them and the errors are gone :)

pip install --upgrade setuptools

For those who want the latest stable version use the above command or you can try yum to install python-setuptools

Hope it helps!

error: Python.h: No such file or directory

noreply@blogger.com (Anonymous) — Mon, 31 Aug 2015 09:05:00 +0000

Okay guys so I was trying to install locust using pip and the installation was failing due to the following error.

"error: Python.h: No such file or directory"

Found out that the python devel package was not installed and hence the error. So I installed the devel package and voila.. things were back on track :)

So in general if you find that something.h file is missing or not found, it usually means that the devel packages are not installed.

#yum install python-devel

Hope this helps someone :)

system failure: POST failed, status=413 upload too large: file '/': upload too large -- Restoring Large Zimbra backups

noreply@blogger.com (Anonymous) — Fri, 07 Nov 2014 05:27:00 +0000

Okay so zimbra account restoration for large accounts ( above 1GB ) was not working for me. the following steps helped to restore large accounts.

What you need to do is to change parameter rest_request_max_upload_size to a larger value. Here we will change it to 10GB.

# su zimbra
# /opt/zimbra/bin/zmlocalconfig -e rest_request_max_upload_size=10737418240
# zmmailboxdctl restart
# exit

Then run the import backup account like this as root user.

# /opt/zimbra/bin/zmmailbox -z -m "email@domain.com" postRestURL "//?fmt=tgz&resolve=reset" backupfile.tar.gz

Thanks to Andrea for the tip :)

ref url: LINK

Ruby installation issue with openssl

noreply@blogger.com (Unknown) — Wed, 20 Aug 2014 08:06:00 +0000

So i was trying to install ruby 1.87 and the compilation broke due to openssl issue. The error was something like this.

ossl_pkey_ec.c: In function ‘ossl_ec_group_initialize’:
ossl_pkey_ec.c:761: warning: assignment makes pointer from integer without a cast
ossl_pkey_ec.c:815: error: ‘EC_GROUP_new_curve_GF2m’ undeclared (first use in this function)
ossl_pkey_ec.c:815: error: (Each undeclared identifier is reported only once
ossl_pkey_ec.c:815: error: for each function it appears in.)
make[1]: *** [ossl_pkey_ec.o] Error 1
make[1]: Leaving directory `/usr/local/src/ruby-enterprise-1.8.7-2012.02/source/ext/openssl'
make: *** [all] Error 1

So applied this patch to the openssl file in the extracted ruby source and finally the compilation was successfull. You will need to specify the location of the ossl_pkey.ec.c file in the below file or you can mention it while patching.

--- ruby-1.8.7-p374/ext/openssl/ossl_pkey_ec.c 2010-06-21 04:18:59.000000000 -0500
+++ /root/ruby-1.8.7-p374/ext/openssl/ossl_pkey_ec.c    2013-12-10 13:30:18.919963527 -0600
@@ -757,8 +757,10 @@
                 method = EC_GFp_mont_method();
             } else if (id == s_GFp_nist) {
                 method = EC_GFp_nist_method();
+               #if !defined(OPENSSL_NO_EC2M)
             } else if (id == s_GF2m_simple) {
                 method = EC_GF2m_simple_method();
+               #endif
             }

             if (method) {
@@ -811,8 +813,10 @@

             if (id == s_GFp) {
                 new_curve = EC_GROUP_new_curve_GFp;
+               #if !defined(OPENSSL_NO_EC2M)
             } else if (id == s_GF2m) {
                 new_curve = EC_GROUP_new_curve_GF2m;
+               #endif
             } else {
                 rb_raise(rb_eArgError, "unknown symbol, must be :GFp or :GF2m");
             }

Change your location to the ruby source directory and save the contents to a file named patch.txt. then issue the following command to patch.

#patch < patch.txt

Hope this helps :)

For those who have Issues running Microsoft Office 2007 on Wine.

noreply@blogger.com (Unknown) — Wed, 06 Aug 2014 05:55:00 +0000

So I had to remove my windows altogether and run linux. I choose the latest stable release of Mint 17, i need to have ms office installed and figured out the wine package should handle this fine. however it was not smooth as i thought.

Installation was fine. But the excel and power point was not opening and had trouble. So here is something that I did made it work for me.

1. Open the wine configuration ( gui --> Configure Wine ) and select the windows version to be "windows xp"

2. Check the libraries tab next, you will need to add a new override for the library, choose "riched 20" and click add. Then you need to edit this newly added override and change the load order to "native ( windows )"

Apply the wine configuration and then try launching the powerpoint or excel, it should work :)

Nagios - Hosts Disappear

noreply@blogger.com (Unknown) — Mon, 26 Aug 2013 08:10:00 +0000

Well I had configured my nagios setup and everything seemed to be fine, then i noticed something strange! The hosts keep disappearing time to time. They do come up at an odd time but not always. Well lot of time was spent on configurations analyzing what went wrong and what ! no LUCK!! :(

So to all those who has this problem, here's something that you might want to check for. Such an issue arises due to more number of nagios PIDs, ie the shutdown of previous nagios was not proper and that PID is messing up with the new one. So to troubleshoot stop nagios, check for orphaned PIDs.. kill it and start nagios again. Voila the hosts started appearing with no issues again!! :)

[root@server ~]#    ps -ef | grep -i nagios
nagios   23581     1 0 Aug22 ?        00:00:00 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg
nagios   24686     1 0 Aug19 ?        00:00:01 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg
root     29749 27976 0 07:14 pts/0    00:00:00 grep -i nagios

[root@server ~]#    /etc/init.d/nagios stop

[root@server ~]#     ps -ef | grep -i nagios
nagios   24686     1 0 Aug19 ?        00:00:01 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg
root     29760 27976 0 07:14 pts/0    00:00:00 grep -i nagios

[root@server ~]#     kill -9 24686

[root@server ~]#     ps -ef | grep -i nagios
root     29762 27976 0 07:14 pts/0    00:00:00 grep -i nagios

[root@server ~]#     /etc/init.d/nagios start
Starting nagios: done.

[root@server ~]#     ps -ef | grep -i nagios
nagios   29791     1 0 07:14 ?        00:00:00 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg
root     29795 27976 0 07:14 pts/0    00:00:00 grep -i nagios

Hard Disk Cloning - Data Recovery

noreply@blogger.com (Unknown) — Thu, 06 Jun 2013 08:50:00 +0000

Okay, you can use various Linux commands that can be used to clone the hard drive. This can be helpful while recovering data.

dd

The simplest program to clone.

Usage:

dd if=/dev/sda/ of=/dev/sdb

It will copy partition table and boot loader and all partitions within this disk

Here "if" option specifies your input and "of" specifies your output.

Make sure that both hard disks are of the same size.

How to get the status of disk cloning. Open a new terminal and issue the following commands.

# pgrep -l dd

56452 dd

# kill -USR1 56452

Here the first command will out put the process id of the dd command and the second command will make dd throw the output in the same shell where its running.

Hope it helps.

Postfix + DKIM setup

noreply@blogger.com (Unknown) — Tue, 11 Dec 2012 07:53:00 +0000

Installation

1) Get the rpmforge repo and install it.

# wget http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm
# rpm -ivh rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm
# yum install opendkim postfix

2) stop sendmail and remove from auto start.

# /etc/init.d/sendmail stop# chkconfig remove sendmail

3) add postfix and opendkim to the autostart pool

# chkconfig postfix on# chkconfig opendkim on

4) configure postfix.

# vi /etc/postfix/main.cf

configuration options: change the following or comment out the existing and add accordingly.

myhostname = server.yourdomainname.com ( your server hostname )mydomain = yourdomainname.commyorigin = $mydomaininet_interfaces = allmydestination = $myhostname, localhost.$mydomain, localhost, $mydomainhome_mailbox = Maildir/

Add the following for DKIM in postfix main.cf

smtpd_milters = inet:localhost:8891non_smtpd_milters = $smtpd_miltersmilter_default_action = acceptmilter_protocol = 2

5) configure Opendkim

Configuration files of OpenDKIM

1. /etc/opendkim.conf – OpenDKIM’s main configuration file
2. /etc/opendkim/KeyTable – a list of keys available for signing
3. /etc/opendkim/SigningTable – a list of domains and accounts allowed to sign
4. /etc/init.d/opendkim — Service start up file.

# vi /etc/opendkim.conf

Configuration options:

PidFile /var/run/opendkim/opendkim.pidMode svCanonicalization relaxed/simpleSyslog yesSyslogSuccess yesLogWhy yesUserID opendkim:opendkimSocket inet:8891@localhostUmask 002Selector defaultKeyTable refile:/etc/opendkim/KeyTableSigningTable refile:/etc/opendkim/SigningTableExternalIgnoreList refile:/etc/opendkim/TrustedHostsInternalHosts refile:/etc/opendkim/TrustedHosts

# cd /etc/opendkim

We will create the public and private keys now.

# cd keys# mkdir yourdomainname.com; cd yourdomainname.com# opendkim-genkey -d yourdomainname.com -s default

here -d denotes your domain and -s is for selector.

# chown opendkim.opendkim ../yourdomainname.com -R

# cd ..# vi KeyTable

default._domainkey.yourdomainname.com yourdomainname.com:default:/etc/opendkim/keys/yourdomainname.com/default.private
# vi SigningTable
*@yourdomainname.com default._domainkey.yourdomainname.com

# vi TrustedHosts
127.0.0.1localhostserver.yourdomainname.comyourdomainname.com

Note: ensure that localhost is mentioned in TrustedHosts file.

Now we are ready to test this. Start opendkim first and then postfix.

# /etc/init.d/opendkim start# /etc/init.d/postfix start

Ensure that OpenDKIM logs has written on mail log file. This is the only file where you ca see any issue with the opendkim errors.

# tail -f /var/log/maillog

Sep 20 09:43:50 server opendkim[8535]: OpenDKIM Filter v2.5.2 starting (args: -x /etc/opendkim.conf -P /var/run/opendkim/opendkim.pid)

Add the DNS records to your domain name. You can get the public dns record from the following file. This is TXT record.

# cat /etc/opendkim/keys/mydomain.com/default.txt

ensure to add a "k" ahead of ;=rsa; by default it will be without k, after the mentioned changes the dns record will have ;k=rsa;

default._domainkey IN TXT "v=DKIM1;k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDJmb2F+hGx+/1Y4dadbsTzg/thhJVsZHT5chFhaoZH6SMALX6J9IIIPSW3NRsap/mUQQ5GVG9IHIBfpAsIJr8CILOVcqAWQbG5XTn9Sk1p76abg3tyR01rhSTG2CljLmkNAPqOSrE5uUEXRq1T+eGhS1EVHFWmQ5lF8ZAyoyEHewIDAQAB" ; ----- DKIM default for yourdomainname.com

Important : Don’t forget to set SPF record that may boost the email delivery.

Send out a test email and verify.

# echo " This is a test mail " | mail -s "OpenDKIM test mail" mygmail@gmail.com

If everything goes well you see a messages “DKIM-Singnature header added” in mail log.

# tail -f /var/log/messages

Sep 20 09:47:33 server opendkim[8535]: 33040108639: DKIM-Signature header added (s=default, d=yourdomainname.com)Sep 20 09:47:33 server postfix/qmgr[2390]: 33040108639: from=, size=3016, nrcpt=1 (queue active)Sep 20 09:47:33 server sendmail[8671]: q8KDlXa9008671: to=mygmail@gmail.com, ctladdr=user@yourdomainname.com (503/503), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=32554, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (Ok: queued as 33040108639)Sep 20 09:47:33 server postfix/smtpd[8636]: disconnect from GF-P-server.yourserver.com[127.0.0.1]Sep 20 09:47:34 server postfix/smtp[8642]: 33040108639: to=, relay=mailin-04.mx.aol.com[205.188.146.194]:25, delay=1.3, delays=0.1/0/0.24/0.95, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as 05217380000B9)Sep 20 09:47:34 server postfix/qmgr[2390]: 33040108639: remove

Check the email header for confirmation : you should see dkim= pass

Hope this helps :)

Quick Setup KVM aka Kernel-based Virtual Machine

noreply@blogger.com (Unknown) — Sat, 13 Oct 2012 06:46:00 +0000

Well, I thought this was something difficult, but trust me its not brain twister to setup the virtual machines using KVM.

Note: This tutorial assumes you understand the basics of linux and aware of the commands usage.

Ok here is how I setup the same.

1. Install CentOS 6 ( minimal Installation )

2. Turn of selinux

# vi /etc/selinux/config

make the following change.

SELINUX=disabled

Now reboot your machine to have this applied.

3. Update the system using yum

4. Install packages for Virtualization to work.

# yum install -y openssh-server openssh-client qemu-kvm libvirt bridge-utils virt-manager.x86_64 virt-top.x86_64 screen

5. Lets setup the network now. For the kvm to work, we will need to setup bridge network. The following is the configuration options.

[root@server ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE="eth0"
NM_CONTROLLED="no"
ONBOOT=yes
HWADDR=00:01:6C:53:82:72
BRIDGE="br0"
[root@server ~]# cat /etc/sysconfig/network-scripts/ifcfg-br0
DEVICE="br0"
NM_CONTROLLED="no"
ONBOOT=yes
HWADDR=00:01:6C:53:82:72
TYPE=Bridge
IPADDR=192.168.1.10
PREFIX=24
GATEWAY=192.168.1.1
DNS1=8.8.8.8

4. Save the settings and open a screen to restart the network.

# screen -S network
# /etc/init.d/network restart

5. Now you should see the bridge network up and running.

6. Start libvirtd

# /etc/init.d/libvirtd start

Oops. it did not start for me :D here's what was missing

# yum -y install avahi

Now libvirtd will start..

7. Copy an ISO to your home directory so that we can use this for creating Virtual Machines, we will be using centos here.

8. Create your VMs now

# virt-install --name=server_name --ram=512 --arch=x86_64 --vcpus=2 --location=/home/packages/CentOS-6.0-x86_64-bin-DVD1.iso --os-type=linux --os-variant=rhel6 --file /home/images/server.img --nonsparse --nographics -s15 --extra-args='console=tty0 console=ttyS0,115200n8' --prompt

9. Use Man pages for exact options.

Hope this helps :)

Unable to install applications using GEM

noreply@blogger.com (Unknown) — Fri, 17 Feb 2012 13:18:00 +0000

I faced an issue today, I was trying to install a package using gem command but ended up in the following error

Building native extensions. This could take a while...
ERROR: Error installing cassandra:
ERROR: Failed to build gem native extension.
/usr/bin/ruby extconf.rb
mkmf.rb can't find header files for ruby at /usr/lib/ruby/ruby.h

So in order to fix this you need to install the ruby-devel package.

you can use yum or rpm or which ever you are comfortable with.

cPanel + mysql slow queries to TABLE_SCHEMA

noreply@blogger.com (Unknown) — Wed, 14 Dec 2011 15:17:00 +0000

If you are seeing the following in mysqladmin proc for a long time then its basically cPanel calculating account disk usage from the information_schema, this tends to increase the load on some servers.

| 14436 | root | localhost | mysql | Query | 2227 | | SELECT TABLE_SCHEMA as DB,SUM(DATA_LENGTH)+SUM(INDEX_LEN
GTH) AS SPACEUSED from information_schema.ta |

You can place the following in your cpanel conifg (/var/cpanel/cpanel.config) to force /scripts/update_db_cache to utilize a `du` style disk calculation. This should help you.

use_information_schema=0

restart cpanel once done :)

Unable to mount hard disk/Partition

noreply@blogger.com (Unknown) — Sun, 27 Nov 2011 16:42:00 +0000

Yesterday I faced a strange issue, after rebooting the server I noticed that our back drives did not mount automatically. The fstab entries were proper but still the device did not mount. I tried manually

# mount /dev/sdb1 /backup

unable to mount /dev/sdb1 /backup busy or already mounted.

Googled a lot but did not find any fix, checked if the raid setup was causing the issue since we had raid setup sometime back ( although it was not in use )

Did the following to fix this ( try as a last attempt if no other method works :D )

root@server [~]# dmsetup ls
ddf1_4035305a0590430220202020202020201d9400003a354a45 (253, 2)
VolGroup00-swap (253, 1)
VolGroup00-root (253, 0)
root@server [~]# dmsetup remove ddf1_4035305a0590430220202020202020201d9400003a354a45
root@server [~]# dmsetup ls
VolGroup00-swap (253, 1)
VolGroup00-root (253, 0)
root@server [~]# mount /dev/sdb1 /backup

root@server [~]# df -h

/dev/sdb1 276G 223G 39G 86% /backup

Hope this helps :)

Cpanel upcp error

noreply@blogger.com (Unknown) — Sat, 20 Nov 2010 03:50:00 +0000

Issue: root@server [~]# /scripts/upcp --force
/scripts/upcp syntax OK
Running Futex Check/Fix......Done
Undefined subroutine &Cpanel::Update::automatic_updates_enabled called at /scripts/upcp line 273.

Solution: wget -O /root/updatenow.static http://httpupdate.cpanel.net/cpanelsync/RELEASE/scripts/updatenow.static && perl /root/updatenow.static --manual

Then run /scripts/upcp --force.

It should fix it!!

mount/Unmount a partition in Linux

noreply@blogger.com (Unknown) — Wed, 27 Oct 2010 07:46:00 +0000

I was trying to umount a partition, it gave me error saying the device is busy and un mount was not working. I then started to troubleshoot this and came to the conclusion that something was still accessing the partition and hence the Linux was not allowing me to unmount it. So what do you do to know what process is using this? There are couple of command utilities that can assist you in this. One is lsof and the other one is fuser, so how do you use this? lets see that below.

# lsof /dev/sda2

# fuser -m /dev/sda2

it will list you the process that is using that partition, either stop the process or kill it and then you can umount it. Hope it helps ;)

Recovering files/settings from a cPanel server from a Harddisk failure/Crash

noreply@blogger.com (Unknown) — Fri, 01 Oct 2010 14:27:00 +0000

Bad things happen...Same is the case with a server, Suppose you have a cPanel server and one fine morning, you get this alert.. Site DOWN!!!

oops your hdd crashed? well dont panick... contact your datacentre and get the same OS installed on a new hdd, lets do the data recovery real fast!

Once the server is UP with new OS, install cPanel and connect your old hdd as slave and mount it to /oldHD

# mount /dev/sdb1 /oldHD

Run these rsync commands to move everything over;

# rsync -vrplogDtH /oldHD/usr/local/apache/conf /usr/local/apache
# rsync -vrplogDtH /oldHD/var/named /var
# rsync -vrplogDtH /oldHD/home/* /home
# rsync -vrplogDtH /oldHD/usr/local/cpanel /usr/local
# rsync -vrplogDtH /oldHD/var/lib/mysql /var/lib
# rsync -vrplogDtH /oldHD/var/cpanel /var
# rsync -vrplogDtH /oldHD/usr/local/cpanel/3rdparty/mailman /usr/local/cpanel/3rdparty
# rsync -vrplogDtH /oldHD/var/log/bandwidth /var/log
# rsync -vrplogDtH /oldHD/usr/local/frontpage /usr/local
# rsync -vrplogDtH /oldHD/var/spool/cron /var/spool
# rsync -vrplogDtH /oldHD/root/.my.cnf /root
# rsync -vrplogDtH /oldHD/etc/httpd/conf/httpd.conf /etc/httpd/conf
# rsync -vrplogDtH /oldHD/etc/sysconfig/network /etc/sysconfig

almost done.. now some configuration files need to be copied.

go to the old etc directory

# cd /oldHD/etc
# rsync -vrplogDtH secondarymx domainalias valiases vfilters exim* proftpd* pure-ftpd* passwd* group* *domain* *named* wwwacct.conf cpupdate.conf quota.conf shadow* *rndc* ips* ipaddrpool* ssl hosts /etc

Once this is complete run

# /scripts/fixeverything
# /scripts/upcp –force
# /scripts/easyapache

everything should be working fine now :)

Extended logging in Exim

noreply@blogger.com (Unknown) — Thu, 08 Jul 2010 08:24:00 +0000

1. Open /etc/exim.conf

#vi /etc/exim.conf

2. Enter the following

log_selector=+all

3. Save the file and change its attribute

# chattr + i /etc/exim.conf

4. Restart Exim

# /etc/init.d/exim restart

Thats it! now check the exim log

# tail -f /var/log/exim_mainlog

Enable Quota in VPS ( openvz )

noreply@blogger.com (Unknown) — Sat, 28 Nov 2009 05:39:00 +0000

If you are experiencing an issue with OpenVZ VPS disk quota, please make sure that the following values are set in the VPS conf.

VPS conf Location : /etc/vz/conf/VEId.conf

In the main node, do the following steps.

1) #grep DISK_QUOTA /etc/vz/conf/VEId.conf

If no disk quota value has found ot it is disabled, change the value to

DISK_QUOTA=yes

2) Check that disk quota is enabled in the main server itself.

grep DISK_QUOTA /etc/sysconfig/vz

If not enable the value to yes in the conf.

DISK_QUOTA=yes

3) Check for the value quotaugidlimit .

#grep -i quotaugidlimit /etc/vz/conf/veid.conf

4) Check the quota module "vzdquota" is loaded or notin main node.

# lsmod |grep -i vzdquota

5) You can set the value quotaugidlimit from the main node using the below command.

vzctl set veid –quotaugidlimit 500 –save

6) Make sure to reboot the mentioned node from the main node.

vzctl restart veid

7) Enter the the node for which you are experiencing the problem.

vzctl enter veid

Type the command 'mount'. It should give a similar output.

# mount
/dev/simfs on / type reiserfs (rw,usrquota,grpquota)
/proc on /proc type proc (rw)
/sys on /sys type sysfs (rw)
none on /dev type tmpfs (rw)
none on /dev/pts type devpts (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)

Also make sure that symbolic links are existing from aquota.group and aquota.user to their respectve physical locations.

# ll
total 64
lrwxrwxrwx 1 root root 39 Oct 19 11:41 aquota.group -> /proc/vz/vzaquota/00000030/aquota.group
lrwxrwxrwx 1 root root 38 Oct 19 11:41 aquota.user -> /proc/vz/vzaquota/00000030/aquota.user

Create VPS nodes in OpenVZ

noreply@blogger.com (Unknown) — Sun, 22 Nov 2009 11:39:00 +0000

Steps for creating nodes in OpenVZ.

1. First of all check if the templates are available. Go to the vz cache directory

[root@server ~]# cd /vz/template/cache

[root@server cache]# pwd
/vz/template/cache
[root@server cache]# ll
total 1356612
-rw-r--r-- 1 root root 158160318 Jul 10 2010 centos-4-x86.tar.gz
-rw-r--r-- 1 root root 158609159 Sep 14 16:11 centos-4-x86.tar.gz.1
-rw-r--r-- 1 root root 130092151 May 13 2008 centos-5-i386-default.tar.gz
-rw-r--r-- 1 root root 191595463 Sep 14 16:16 centos-5-x86_64.tar.gz
-rw-r--r-- 1 root root 180022352 Apr 26 2010 centos-5-x86.tar.gz
-rw-r--r-- 1 root root 212917989 Sep 14 16:25 centos-6-x86_64.tar.gz
-rw-r--r-- 1 root root 117087334 Nov 12 2010 debian-4.0-x86.tar.gz
[root@server cache]#
[root@server cache]#

if you do not have any templates you can download the precreated templates from the openvz website

http://wiki.openvz.org/Download/template/precreated

Once downloaded follow the steps below to create the nodes.

[root@server ~]# vzctl create 101 --ostemplate centos-5-i386-default --config vps.basic
[root@server ~]# vzctl set 101 --onboot yes --save
[root@server ~]# vzctl set 101 --hostname training.server.com --save
[root@server ~]# vzctl set 101 --ipadd 192.168.0.101 --save
[root@server ~]# vzctl set 101 --nameserver 4.2.2.2 --save
[root@server ~]# vzctl start 101
[root@server ~]# vzctl exec 101 /etc/init.d/sshd start
[root@server ~]# vzctl exec 101 passwd

Hope this helps!

cpDav service failed : Solution

noreply@blogger.com (Unknown) — Sun, 22 Nov 2009 11:25:00 +0000

There have been a number of tickets (and a few forum posts), regarding emails for the perl modules Net::DAV::Server and XML::LibXML not being installed properly.

It turns out this is an issue with the libxml2 package (not the perl module) on 64-bit CentOS systems.

Anyone encountering this, here is the fix (from the cPanel 11 release notes):

CODE

Issue: Conflicting libxml installs cause cpdavd (Web Disk Server) to fail. 64 bit linux only
Symptoms: cpdavd won’t start, running /usr/local/cpanel/bin/checkperlmodules shows that XML::libXML will not install and Net::DAV::Server will not install

Solution: Run https://your.IP.here:2087/scripts2/autofixer and enter libxml64fix.

This fix downloads the libxml2 source code and compiles the newest versions. The yum package manage apparently doens't have the latest version for CentOS in their repository, I guess.

Here's a relevent Cpanel forums topic:
http://forums.cpanel...ead.php?t=67047

cPanel Logs

noreply@blogger.com (Unknown) — Sun, 22 Nov 2009 11:13:00 +0000

Applications can log the system activity in two ways, one being according to their autonomous logic & the other through the system’s log daemon, well know as syslog..
The syslog daemon’s configuration file /etc/syslog.conf contains all the necessary paths/locations as to where the logs are stored.
Usually the directory /var/log/ is used for the system logs but other applications use the applications specified directories to store their log files…
Many distributions provide tools to manage and analyze the system logs.
Logrotate is a well known log rotation tool which usually is configured in the /etc/logrotate.conf file.
It may also have additional package-defined configurations in the /etc/logrotate.d/ directory..
In order to understand what’s happening on the system a brief analysis of /etc/syslog.conf is mandatory for checking the main logs positions.
Here are some basic log files, their locations & a brief description which can be found in Linux distros [mostly in cPanel ]:
General:
Quote:
cPanel/WHM Initial Installation Errors:
Location : /var/log/cpanel*install*
Description : These log files contain cPanel installation logs & should be referenced first for any issues resulting from new cPanel installations..
Quote:
Cpanel/WHM Service Status Logs:
Location : /var/log/chkservd.log
Description :The service monitoring demon (chkservd) logs all service checks here. Failed service are represented with a [-] and active services are represented by [+].
Quote:
Cpanel/WHM Accounting Logs:
Location : /var/cpanel/accounting.log
Description : Contains a list of accounting functions performed through WHM, including account removal and creation..
cPanel/WHM Specific Requests and Errors:
Quote:
cPanel error logs:
Location : /usr/local/cpanel/logs/error_log
Description : cPanel logs any error it incurs here. This should be checked when you encounter errors or strange behavior in cPanel/WHM…
Quote:
cPanel License Error Logs:
Location : /usr/local/cpanel/logs/license_log
Description : All license update attempts are logged here. If you run into any errors related to license when logging in, check here.
Quote:
Stats Daemon Logs:
Location : /usr/local/cpanel/logs/stats_log
Description : The stats daemon (cpanellogd) logs the output from all stats generators (Awstats, Webalizer, Analog) here.
Quote:
Client Information, Requested URL Logs:
Location : /usr/local/cpanel/logs/access_log
Description : General information related to access cPanel requests is logged here.
Quote:
cPanel/WHM Update Logs:
Location : /var/cpanel/updatelogs/update-[TIMESTAMP].log
Description : Contains all output from each cPanel update [upcp]. It’s named with the timestamp at which the upcp process was initiated..
Quote:
Bandwidth Logs:
Location : /var/cpanel/bandwidth
Description : Files contain a list of the bandwidth history for each account. Each named after their respective user.
Quote:
Tailwatchd [New]:
Location : /usr/local/cpanel/logs/tailwatchd_log
Description : Logs for daemon configuired under tailwatchd ie. cPBandwd, Eximstats, Antirelayd.
Apache Logs:
Quote:
General Error and Auditing Logs:
Location : /usr/local/apache/logs/error_log
Description : All exceptions caught by httpd along with standard error output from CGI applications are logged here..
The first place you should look when httpd crashes or you incur errors when accessing website.
Quote:
Apache SuExec Logs:
Location : /usr/local/apache/logs/suexec_log
Description : Auditing information reported by suexec each time a CGI application is executed. Useful for debugging internal server errors, with no relevant information being reported to the Apache error_log, check here for potential suexec policy violations…
Quote:
Domain Access Logs:
Location : /usr/local/apache/domlogs/domain.com
Description : General access log file for each domain configured with cPanel.
Quote:
Apache Access Logs:
Location : /usr/local/apache/logs/access_log
Description : Complete web server access log records all requests processed by the server.
Exim :
Quote:
Message Reception and Delivery:
Location : /var/log/exim_mainlog or /var/log/exim/mainlog
Description : Receives an entry every time a message is received or delivered.
Quote:
Exim ACLs/Policies based RejectLog :
Location : /var/log/exim_rejectlog
Description : An entry is written to this log every time a message is rejected based on either ACLs or other policies eg: aliases configured to :fail
Quote:
Unexpected or Fatal Errors:
Location : /var/log/exim_paniclog
Description : Logs any entries exim doesn’t know how to handle. It’s generally a really bad thing when log entries are being written here, and they should be properly investigated..
Quote:
IMAP/POP/SpamAssassin General Logging and Errors:
Location : /var/log/maillog & /var/log/messages
Description : The IMAP, POP, and SpamAssassin services all log here. This includes all general logging information (login attempts, transactions, spam scoring), along with fatal errors.
FTP:
Quote:
FTP Logins and General Errors:
Location : /var/log/messages
Description : General information and login attempts are logged here..
Quote:
FTP Transactions logging:
Location : /var/log/xferlog or /var/log/messages
Description : Is a symbolic link in most cases to /usr/local/apache/domlogs/ftpxferlog, which contains a history of the transactions made by FTP users…
MySQL:
Quote:
MySQL General Information and Errors :
Location : /var/lib/mysql/$(hostname).err
Description : This path could vary, but is generally located in /var/lib/mysql. Could also be located at /var/log/mysqld.log
Security:
Quote:
Authentication attempts:
Location : /var/log/secure
Description : Logs all daemons which requires PAM Authentication.
Quote:
Tracking all Bad Logins and Logouts:
Location : /var/log/btmp
Description : Log of all attempted bad logins to the system. Accessed via the lastb command..
Quote:
Tracking all Logins and Logouts:
Location : /var/log/wtmp
Description : The wtmp file records all logins and logouts.
Quote:
Last Logins:
Location : /var/log/lastlog
Description : Database times of previous user logins. The lastlog file is a database which contains info on the last login of each user.
Quote:
WebDav or WebDisk Log :
Location : /usr/local/cpanel/logs/cpdavd_error_log
Description : The cpdavd daemon is “WebDav” (better known as “WebDisk”) which was introduced in cPanel 11 to allow users to mount their home directory on their personal computer, always having access to the files and content…
Quote:
Cphulkd Logs:
Location : /usr/local/cpanel/logs/cphulkd_errors.log
Description : cPHulk Brute Force Protection prevents malicious forces from trying to access your server’s services by guessing the login password for that service….
It blacklists IPs that it thinks are trying to run a brute force attack.
Quote:
Failure Logging:
Location : /var/log/faillog
Description : Faillog formats the contents of the failure log from /var/log/faillog database. It also can be used for maintains failure counters and limits. Run faillog without arguments display only list of user faillog records who have ever had a login failure.
Quote:
Startup/Boot, Kernel & Hardware error messages :
Location : /var/log/dmesg
Description : dmesg is a “window” into the kernels ring-buffer. It’s a message buffer of the kernel. The content of this file is referred to by the dmesg command. It shows bootlog and the hardware errors..

How to change your Exim outgoing mail IP, A Quick setup

noreply@blogger.com (Unknown) — Sat, 07 Nov 2009 05:32:00 +0000

1. Open the file /etc/mailips

[root@server ~]# vi /etc/mailips

enter the following and save the file

*: IP

example: *: 192.168.0.10

assuming 192.168.0.10 is your secondary IP.

IP - the IP you wish to send emails from. The * symbol specifies all domains to send emails from this IP

2. Now edit /etc/mail_reverse_dns

Enter the reverse DNS aka rDNS for the above IP and save the file

IP rdns

Example: 192.168.0.10 server.mail.com

3. Now change the attributes to immutable

[root@server ~]# chattr +i /etc/mail_reverse_dns
[root@server ~]# chattr +i /etc/mailips

4. Restart exim and thats it!

[root@server ~]# /etc/init.d/exim restart

Send a test email as root and check the headers to confirm.

Hope this helps :)

Useful Exim Commands continued...

noreply@blogger.com (Unknown) — Wed, 05 Aug 2009 11:32:00 +0000

[1] Removing Bad Mail

for i in `exiqgrep -i -f nobody`; do exim -Mrm $i; done >> Removes Nobody Mail

for i in `exiqgrep -i -o 259200`; do exim -Mrm $i; done >> Removes Mail Older than 3 Days

for i in `exiqgrep -i -f "^<>$"`; do exim -Mrm $i; done >> Removes Mail with Weird Characters (Spam)

[2] Delete Mail by a Domain

for i in `exiqgrep -i -f domain.com`; do exim -Mrm $i; done

[3] Delete Mail for a Domain

for i in `exiqgrep -i -r domain.com`; do exim -Mrm $i; done

[4] Remove Whole Mail Queue

for i in `exiqgrep -i -f `; do exim -Mrm $i; done

[5] Run Mail Queue

runq -qqff&