Patch the Linux Kernel Without Reboots

evanbro writes "ZDNet is reporting on ksplice, a system for applying patches to the Linux kernel without rebooting. ksplice requires no kernel modifications, just the source, the config files, and a patch. Author Jeff Arnold discusses the system in a technical overview paper (PDF). Ted Ts'o comments, 'Users in the carrier grade linux space have been clamoring for this for a while. If you are a carrier in telephony and don't want downtime, this stuff is pure gold.'" Update: 04/24 10:04 GMT by KD : Tomasz Chmielewsk writes on LKML that the idea seems to be patented by Microsoft.

Re:Unless it fails.

[Anonymous Coward]

honestly how much downtime are we talking here? 30 seconds?

well, think about the fsck that happens after 180 days or 30+ mounts ?

Re:Wrong way to solve the uptime problem

[Qzukk]

Trust me, that was the first thing they thought of, then the CEO came in and said "Why are you ordering more equipment when we have half of our machines sitting there and doing nothing? We could be doing twice the work/traffic/whatever without paying more money!"

Re:Maybe...

[CogDissident]

I thought their working slogan was:

Windows 7, it's not awful like Vista!

The real test...

[hal2814]

Can ksplice be installed without rebooting?

Re:Needed that bad?

[tgatliff]

I guess a better way to put it would be "oh... Way Cool!!!!"... :)

Meaning, yes I agree that in most cases it is not needed, but I have internal processing servers that have up times of over 3 years, so if I had something like this probably all my servers would have up times of this long..

Re:In Soviet Russia,

[oodaloop]

Let's get the rest of the usual jokes out of the way while we're at it.

If there were no kernel, it would necessary to create our non-rebooting robot overlords are belong to Chuck Norris.

Re:Amazing

[katz]

Considering that you don't need to prepare the kernel in any way--just execute the program and bang, it's patched--means that someone with root access could slip a rootkit right under your nose (i.e., without the system administrator being aware of this).

- Roey

Re:Wrong way to solve the uptime problem

[Anonymous Coward]

If he knew anything, he wouldn't be the CEO.

Sorry...

[PJ The Womble]

This is old news down in the South.

They don't bother splicing. Them good ol' boys been big on Kernel Sanders for years now.

Re:Impressive hack

[EriktheGreen]

Well, let's see.

A silver dollar, from which bits were commonly cut, weighs about .77 troy ounces.

Today's gold price as of posting is about $889.95 US per troy ounce.

A silver dollar was typically cut into 8 bits, which gives us a weight per bit of 0.096 ounces. That translates to about $85.66 per bit weight in gold. Remember, this is per system being patched.

Since the patches being applied ranged from 1 line to 285 lines per the paper, and a reasonable estimate of compiled average bytes per line is something like 20, we get a value of $13,700 per line of patch in gold. Even for the smaller patches, this is significant. The largest patch would be worth nearly $4,000,000 USD in gold.

Of course, for 64 bit systems vs. 32 bit, the value would be twice as much :)

Erik

Re:In Soviet Russia,

[oodaloop]

"But does it run linux?"

That's a joke? I thought that was just one dedicated user who kept asking on every article.

Re:Gates Was Right

[DragonTHC]

I love anything that makes a billionaire whine.

Re:Needed that bad?

[Anonymous Coward]

what takes it out of rotation? it's turtles all the way down.

What!? Unpossible!

[Linux_ho]

This is GPL'd software. Bill Gates told me nobody could improve it. These Linux developers are truly renegades!

Re:Not only the CEO

[DraconPern]

You are running Java. If you port your application to another language, you will automatically get a 10% boost in effeciency. Oh, and save money to buy 5 machines instead of 4.

Re:No, No, No and No again.

[Anonymous Coward]

one-node clusters

Of all the industry oxymorons out there, this is one of the most annoying.

One-goose gaggle.

Single-wheel bicycle.

Re:Needed that bad?

[Anonymous Coward]

no need to reboot to add reiser4 support. All somebody needs to do is work out some complex dependency resolution tool

I thought Hans Reiser had already developed a highly effective method for resolving his dependents.