Linux and Unix

Wednesday, April 02, 2008

Okay, i’ve done it and you probably have too, but when google does it…

Gmail… locked up…

“Still working....” it says at the top.

“Unable to reach Gmail.  Please check your internet connection.”

I like that.  It makes me think it is MY fault that I can’t reach the great goog.

well, I can post this, so my internet must be working.

“And we’re back...”

It now says.

I guess they are…

Nope, gone again.

Oh, back again.

Hmm… bad day to be goog.  I guess someone needs to go back in time and send them an e-mail that they are having problems.

Friday, March 14, 2008

cuchunk cuchunk cuchunk

"Dude, what’s the deal with your server?”

That was the question I was asked today.

My response… “I don’t know… I’ll check it at lunch.”

When I got home, that the noise that I heard was “cuchunk cuchunk cuchunk”.

I *think* I have everything backed up as of 12/12/07… three months ago…

sigh..

So, we are back to just before Christmas....

If you find something missing that you think was there before this date… let me know as I probably have it, but haven’t restored it yet.

There were a number of databases that I didn’t restore.  I got the ones that I thought were active.

I restored homes and /etc/passwd type files…

my apologies....

David

Wednesday, January 09, 2008

System administrator convicted of logic bomb

"Medco sys admin gets 30 months for planting logic bomb” see story at http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=9056284&intsrc=hm_list

Obviously there are several things going on here…

1) The dude was stupid and not a good programmer
2) While the media called the trick “sophisticated” it obviously wasn’t.
3) Medco doesn’t have a good system to monitor changes to their systems.  If nothing else, it should have caught the cron or at job the sys admin used to schedule the job
4) He got 30 months and then 2 years probation and not allowed to touch a computer while in jail - seems like a small punishment to me.

A related story (http://computerworld.com/action/article.do?command=viewArticleBasic&taxonomyName=cybercrime_and_hacking&articleId=9038218) is about his conviction.  The first story is his sentencing.  He was convicted in September and not sentenced until Jan 8th.  So much for timeliness in the judicial system!

Friday, January 04, 2008

Beating the averages, a second look

A friend of mine sent me a link to the article ”Beating the Averages”, which I read in 2001. I read it again today, and best I can tell, I have come up with the same answer I had back then. That is, the most important statement in the whole article, while it has a lot of good and important things to say throughout, is this line which starts the eleventh paragraph:

Robert and I both knew Lisp well

You have to use a programming language your programmers know and know well. If your programmers know more than one language, then, sure, you get other choices. However, this leads me to my second point which is that once you are ready to outgrow your initial programmers - be that attrition, death, growth, or one of any other number of reasons, you have to be able to get more programmers.

LISP is a fantastic language. I would argue that it was and is ahead of the rest for many of the same reasons the author talked about in 2001. I supported the Artificial Intelligence group at Boeing for about 6-8 months. They programmed in Lisp. It was quite impressive. And, they learned those languages in thos fancy academic institutions they got their degrees from - Carnegie Mellon University, MIT, Cal Tech, etc.

FYI, LISP was developed in the late 50’s at MIT.

People who know LISP, in my mind, are real programmers. People who know LISP probably know a half dozen other languages too. These type of people are the programmers who really understand and are examples of the phrase, “Use the right tool for the job”. I am not saying that you can’t be a “real programmer” without knowing LISP. Please do not fall into this or any other fallacy.

Fortunately for me, I do not work for a startup looking to find a competitive advantage to have the chance of staying alive. Unfortunately for me I work in an area that has few people who have graduated from programs that even have heard of LISP or for that matter anything beyond VB, , C Sharp, and MAYBE Perl or PHP. I would be more likely to find around here where “html” is considered a programming language. (Go Michigan!) (Okay, to give them a little break, that page is from 1996, but it is still up, so I can’t give them too much of a break.) Or, you go here, and find that it is listed in the drop-down as an option under “programming languages” and is listed in the text as well.

Overall, the article is a good article. However, my job as a technologist, and especially as a technology manager, is to read such articles and then to see the reality in them. I would encourage others to do the same (starting with this one).

Friday, June 15, 2007

Sometimes, I just want to scream at “somebody”

There are people in this world I despise.  I don’t know who they are, but they are out there.  They are the people that make your life frustrated for no other reason than they “just didn’t think about it” or “oh, I meant to do that, but didn’t get around to it” or “hmm… that’s a good idea, and then ignore the idea” or some other such reason…

Today’s frustration… ethernet cards and upgrades.

I have a linux box.  This box was on Fedora Core 4.  This is old.  However, the box works, so why mess with a good thing.  Well, I decided I would remotely upgrade the box using yum.  This is a scary thing in and of itself.  So, I looked up directions and pieced together a plan from several different web sites… basically, all I need to do to go from FC4 to FC7 is to upgrade to 5, then upgrade to 6, then upgrade to 7.

check your version with uname
uname -a
clean up any left over cruff in yum
yum clean all
make sure you have the latest kernel for your current runlevel
yum install kernel
reboot
clean up any old kernels you have
yum remove kernel-2.
change your location for your packages to the 5 release
rpm -Uhv http://download.fedora.redhat.com/pub/fedora/linux/core/5/i386/os/Fedora/RPMS/fedora-release-5-5.noarch.rpm
update yum
yum update yum
update everything else
yum update
fix any selinux crap (you don’t understand it anyway)
/sbin/fixfiles relabel
remove selinux (not necessary, but makes my life easier!)
check modprobe.conf to make sure you have the right ethernet drivers for your new kernel
reboot
check, you should be on fc5 now
uname -a
change package location for the 6 release
rpm -Uhv http://download.fedora.redhat.com/pub/fedora/linux/core/6/i386/os/Fedora/RPMS/fedora-release-6-4.noarch.rpm
clean your left over cruff in yum
yum clean all
update yum
yum update yum
update everything else (hmm.. wonder why I didn’t do the -y before… shrug)
yum -y update
When I did that, i got 3 warnings

warning: /etc/passwd created as /etc/passwd.rpmnew
warning: /etc/pam.d/system-auth created as /etc/pam.d/system-auth.rpmnew
warning: /etc/ldap.conf created as /etc/ldap.conf.rpmnew

Well, passwd is important, but the other two are not in our environment…
So, for the other two I just copied the new version over the old version.
I figured they added or changed some of the system users which is why there was a new passwd file.
So, I appended my passwd file to the new one, and then removed any of the duplicates (ensuring that username, uid, and gid had not changed)
Now, here was my first mistake.  What I did was

cat passwd >> passwd.rpmnew
vi passwd.rpmnew
mv passwd.rpmnew passwd

When I was vi’ing the passwd.rpmnew file, I kept the stuff at the top, and removed duplicates down below.  This meant that I kept the new versions of accounts like root, bin, daemon, adm, etc.

Now, I don’t know why they did it, but I didn’t notice it.  Well, I noticed it after I couldn’t log in as root.  What I didn’t notice was that the new password file had a * in the second field instead of an x.  Golly, this shouldn’t be a big deal, right? 

WRONG.

A * means not-log-in-able, an x means look in the shadow file for the password. (simple version of what it means.)

So, you cannot log in as root anymore.

Oh, and there was another problem.  eth0 now no longer worked.  eth1 did, but not eth0, but I’ll get to that screammer in a minute.

Okay, so now I can’t fix eth0 and I can’t log in as root…

sigh…

down to the colo I go…

Now, here is the trick to getting back root…

1) Don’t take any CD’s with you - they just get in the way.
2) reboot the box.
3) hit the space bar when grub is loaded and append a line to the kernel start
4) okay, I’ll tell you… that line is “init=/bin/bash”
5) this boots you to a bash prompt.  The next thing you need to do is remount / rw instead of ro. 
mount -o remount,rw /
Yes, there is a way of telling init to do both, but I didn’t have that syntax on the tip of my fingers… so I did it as two steps… ( I *think* I could have done init=/bin/bash rw and it would have done the remounts for me, but I did not test that particular theory and went with what I knew worked.
6) edit /etc/passwd and save
7) if you are being a good admin, you would then set / to be readonly (mount -o remount,ro /), but i’m not a good admin apparently, because I pushed the big button on the front of the box and cycled it.

Root is back. 

Of course, I could have also cleared out root’s password in /etc/shadow if I couldn’t remember the password, but that wasn’t necessary in this case.

Okay, so I got root back, but what about this pesky eth0?

Well, lets make a long story short…

it was e100

that didn’t work (although it had in fc4 and fc5).

I tried a couple other kernel objects… they didn’t work..

I searched the internet…

Finally I found the following:

I have found that in some cases under FC5 and FC6 the e100 in my laptop
winds up with an odd device name, under FC5 it was dev(nnnnn) and under
FC6 it gets a name with tmp in the name.

The fix is to cycle the module with
rmmod e100 ; modprobe e100

at http://www.linux.ie/lists/pipermail/ilug/2006-October/090599.html

That’s just stupid… i’ve booted this box several times.  I’ve changed the modules several times… this can’t possibly work…

rmmod e100
modprobe e100
service network start

Network works…

oh, vey!