Thursday, August 16, 2012

Linux - how to show the memory usage per process

Top is a very useful command to show real time overall system health like CPU,memory and  swap status
 
But when come to memory leak detection, we will need more detail information like which process consumes how much memory

Command below comes handy:-
ps -e -orss=,args= | sort -b -k1,1n | pr -TW$COLUMNS

Thursday, August 2, 2012

Disable Auto-Restart after Windows Update

If you often receive alert at 3 in the morning about your lovely Windows servers restart by itself.

Chances are Auto-restart has been set to on on Windows Update configuration and Windows Update is normally scheduled to restart at 3:00a.m. by default.

To disable Auto Restart after Windows Update. You can set it from Group Policy.

Run gpedit.msc

Computer Configuration-> Admin Template->Windows Component-> Windows Update
Enable - No auto-restart with...

You can now have a good night sleep. Zz.zz..

Authenticating Linux against Active Directory

When you only have few Linux machines and sysadmins, a simple local machine authentication would do a fairy good job.
Imaging if you have 64 Linux box(and growing) and 4 sysadmins. To keep and maintain sudo access up-to-update would be a daunting task.
Why not get Linux and Windows talk to each other if you already have Active Directory on your environment?
- First you will need to ensure Linux machine A record added to AD DNS server
- create a AD group called linixadmin and add admin user to the group
- Next run the following command on Linux client box

yum install samba-common samba-winbind pam_krb5 sudo authconfig;
chkconfig winbind on;
mkdir /home/[your domain name-mycompany];
chmod 0777 /home/mycompany;
echo "%linuxadmin ALL=(ALL) ALL" >> /etc/sudoers;


authconfig \
--disablecache \
--enablewinbind \
--enablewinbindauth \
--smbsecurity=ads \
--smbworkgroup=MYCOMPANY \
--smbrealm=MYCOMPANY.LOCAL \
--enablewinbindusedefaultdomain \
--winbindtemplatehomedir=/home//%U \
--winbindtemplateshell=/bin/bash \
--enablekrb5 \
--krb5realm=MYCOMPANY.LOCAL \  
--enablekrb5kdcdns \
--enablekrb5realmdns \
--enablelocauthorize \
--enablemkhomedir \
--enablepamaccess \
--updateall \

net ads join -U "AD Admin account i.e. joesoh";
 
service winbind restart
===
Note: MYCOMPANY.LOCAL is your AD domain name
Try logon using you Windows ID and password.
Now who says Windows and Linux don't talk?