How to change iLo hostname on HP Proliant servers - SOLVED and EXPLAINED

In case you have or administrating HP Proliant servers then you probably know what iLo is. iLo is short from integrated Light-out. On every HP server there is a small chip where iLo is located. So what is iLo? iLo is some kind of hardware monitoring web GUI. iLo is always working but to approach  to iLo you need IP address. There is default username and password that is located on small paper card that comes with server. Default username is Administrator and password is 8 character random combination of letters and number. Remember that password is case sensitive. It is wise NOT to change password for user Administrator. It is wise to create new user.  

What is iLo hostname? 

This in red square is iLo hostname. Basically, it is name of iLo chip. You can name it Chip if you like but it is wise that iLo hostname is same as server hostname? Why? Well, think of this situation. You need to reboot server called server1 that has iLo address 30.30.30.31. You will see above picture. Here you can see iLo firmware version and iLo hostname. Does iLo hostname ILOFAKENAME mean anything to you? Usually, it does not. So you log in and reboot the server. 20 seconds later you CTO call and ask why server server2 is down. Yea, you rebooted wrong server. That is wise to change iLo hostname to server name.

Ok. Lets change iLo hostame on HP Proliant server.

Step1. Login to iLo. You will see something like this

Step2. Go to Network on left menu.

Step3. Change iLo Subsystem Name(Host Name) to name you will be familiar with. For this test we will change it to myserver. 

For these changes to take affect you have to reset iLo chip. This has absolutely no effect on server. THIS WILL NOT REBOOT SERVER BUT ONLY iLO chip.

Step4. Wait for iLo to reset and see this changes.

That is it. This takes only few minutes to change but can really save you a lot of time.

Or you can see this on Youtube!

 

High CPU load because of ksoftirqd processes cause by LEAP second issue - SOLVED

 High CPU, ksoftirqd, LEAP second - SOLVED EXPLAINED

In case that your server start to act funny, funny like slow response time, high CPU load, etc. first thing that you do it to execute top command. In case your top looks something like this

 you know that something strange is going on. CPU load is very, very high! My first guess was that something is wrong with java application that this server is running. But when I notices that other servers have same issue(very high CPU load), I new that something strange is happening because those server very on different locations, different platforms(hardware, virtual), different OS(but all Linux) and different application were running on them(DB,java,etc.). Also I noticed these ksoftirqd  processes. They did not use so much CPU but it's strange that they are so high in top CPU list.

High CPU load because of ksoftirqd processes

So, all servers with issues had same problem - ksoftirqd process is causing this! What is ksoftird?

ksoftirqd is a per-cpu kernel thread that runs when the machine is under heavy soft-interrupt load. Soft interrupts are normally serviced on return from a hard interrupt, but it's possible for soft interrupts to be triggered more quickly than they can be serviced.

So these soft interrupts if from some reason causing other process (like java process) to use too much CPU.

What caused this? And why? To be worst, I rebooted one server with high CPU load because of ksoftirqd processes but this did not helped!

High CPU load because of ksoftirqd processes cause by LEAP second issue - SOLVED  

After few hours of searching on Internet what can be cause of this, I remembered that I saw a news and that then mention that "tonight" (night before problem started) there is going to be one extra second and that it is something that is normal and every few year extra second is added. I continue to search for solution and then on one forum I read that someone is mentioning "leap" second. What is leap second?

From Wikipedia:

A leap second is a one-second adjustment that is occasionally applied to Coordinated Universal Time (UTC) in order to keep its time of day close to the mean solar time, or UT1. Without such a correction, time reckoned by Earth's rotation drifts away from atomic time because of irregularities in the Earth's rate of rotation. 

 

The NTP packet includes a leap second flag, which informs the user that a leap second is imminent. This, among other things, allows the user to distinguish between a bad measurement that should be ignored and a genuine leap second that should be followed. It has been reported that never, since the monitoring began in 2008 and whether or not a leap second should be inserted, have all NTP servers correctly set their flags on a December 31 or June 30.This is one reason many NTP servers broadcast the wrong time for up to a day after a leap second insertion

So I start to search for this leap second issue solution as possible cause of my problem because it was 1.7.2015.

How to solve this leap second that is causing high CPU load because of ksoftirqd processes?

# date -s now

As soon as I execute this, CPU load start do drop! In a 2 minutes CPU load was back to normal.

CRON job not running marked as UNSAFE - SOLVED

Yesterday I came across strange problem. I created new user on server. Lets call it user12_ABCDE. This user should run certain script periodically for simple FTP transfer. Of course crontab is used. When I run script manually it runs perfectly! When I put it in crontab, nothing happens! I check my  /var/log/messages and find this

Aug  4 16:01:01 server /usr/sbin/cron[27897]: (user12_ABCDE) UNSAFE (user12_ABCDE)

So... I start to google it! On lots of places you can find that it is usually permission issue. I check permission but every thing is OK. 

All other users can run their script in crontab with no problems. UNSAFE error message is only for this user12_ABCDE. 

After some time I run in to this sentence  about cron and UNSAFE

Some O/S restrict the range of characters in a username - some don't. - See more at: http://compgroups.net/comp.unix.admin/cron-fails-with-unsafe-in-log/51152#sthash.mUlmf92A.dpuf

 Some OS restrict the range of character in a username

This put a bug in my ear...

I checked all other user names with this new one. All users have small letters, underscore except this new user that have capital letters in his name. So... I create new user called user12_abcde and try do run crontab. It runs with no problem! Hm... So this cron job not running marked as UNSAFE is only because I have capital letters is my username.  

P.S.

I do not know if this issue is solved on newer Linux distros. I have this issue on SLES 10 kernel 2.6.16.21-0.8-smp.

Some O/S restrict the range of characters in a username - some don't - See more at: http://compgroups.net/comp.unix.admin/cron-fails-with-unsafe-in-log/51152#sthash.mUlmf92A.dpuf

Some O/S restrict the range of characters in a username - some don't - See more at: http://compgroups.net/comp.unix.admin/cron-fails-with-unsafe-in-log/51152#sthash.mUlmf92A.dpufSom

Some O/S restrict the range of characters in a username - some don't. - See more at: http://compgroups.net/comp.unix.admin/cron-fails-with-unsafe-in-log/51152#sthash.mUlmf92A.dpuf

Some O/S restrict the range of characters in a username - some don't. - See more at: http://compgroups.net/comp.unix.admin/cron-fails-with-unsafe-in-log/51152#sthash.mUlmf92A.dpuf

Some O/S restrict the range of characters in a username - some don't. - See more at: http://compgroups.net/comp.unix.admin/cron-fails-with-unsafe-in-log/51152#sthash.mUlmf92A.dpuf

What responsive mean in web site world?

A few days ago, Google finally change it's ranking mechanism and started to count if your web site is responsive or not! If you are simple "dumb" web admin, then you probably don't know what that means. By "dumb" I mean you are person who uploads posts, images, videos and you technical knowledge about web sites is limited.

What responsive web site means?

Responsive web site means that web site can adjust to viewer device. Meaning? These days devices that can look web site are phones, tablets, laptops, netbooks, PC. Have I mention it all? Before smart phones,tablets and netbooks came there were just a PC and laptop. PC have 100% of market but over time laptops become affordable. Same thing happend with tables and smart phones. Major difference between all these devices? Screen size! It's not the same when you look something on display that is  320x480, 600x800, 768x1024 or 1366x768.  Over time PC from majority became minority in terms of devices. Because of this, philosophy in web pages changed. People are more into mobile devices with smaller screens! Because of these, issues like not seeing whole page on small screen start to bother more and more people! And then programmers start to make web pages that can adopt to screen site of the device! So no matter on what you are looking web page, you will see all content! That means responsive!

Lets see what this means on two examples!

Here is one responsive 

http://name4mycat.com/

and one non responsive web site

http://peppapigonlinegames.blogspot.com/

Try to open both sites on your tables and PC and you will know why responsive web sites are a very good and smart thing!

Rename LV how to do it what and what you should be aware of

In case that you need to rename one or more logical volume, here is what you need to do.
Rename logical volume is pretty simple.

#lvrename VolumeGroupName OldLogicalVolumeName NewLogicalVolumeName 

Ok, so you rename logical volume but .... will you have save reboot? Here is few things you should be aware of.

1. Make changes in /etc/fstab
In case you forgot to do that, you will have problems once you reboot you system

2. In case you have renamed logical volume that was mounted on / you need to make changes in /boot/grub/menu.lst and make changes where ever you have old logical volume name.

That is it!



 

SOLVED Argument list too long bash issue for rm, ls, mv, cp

In case you have folder with many files and you want to list, move, copy or delete them you will see this message

#:rm -rf files*
-bash: /bin/rm: Argument list too long
#:ls |wc -l
120407

Why this is happening? To say it in a simple way, you have to many files. Why this is a problem? Linux see that you have to many files and he is not able to do things (in are case rm, cp, ls or mv operations) because there is to many files. This have nothing do to with file size. Just with numbers of files. How to solved this? 

When I see this  Argument list too long message I always use for loop.

It goes like this

#:for i in `ls`;do rm -rf $i;done

And problem is solved.

Hope it helps! :)

HP DL 560 G8 reboot time

In case that you are wondering how much time it takes for HL DL 560 G8 server to reboot, here is answer for you!
Here is some hardware specs:
-128GB RAM
-Intel(R) Xeon(R) CPU E5-4640 0 @ 2.40GHz  x4


OS: SLES11


It takes about 11 minutes from reboot command to log in screen after reboot. So in case that you are in a hurry for quick reboot be prepared to wait a bit. It takes too long for all hardware checks to finish!