Linode Turns 12! Here's Some KVM!

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Linode turns 12! Here’s some KVM!

June 16, 2015 12:01 pm

Happy 12th birthday to us!

Welp, time keeps on slippin’ into the future, and we find ourselves turning 12 years old today. To celebrate, we’re kicking off the next phase of Linode’s transition from Xen to KVM by making KVM Linodes generally available, starting today.

Better performance, versatility, and faster booting

Using identical hardware, KVM Linodes are much faster compared to Xen. For example, in our UnixBench testing a KVM Linode scored 3x better than a Xen Linode. During a kernel compile, a KVM Linode completed 28% faster compared to a Xen Linode. KVM has much less overhead than Xen, so now you will get the most out of our investment in high-end processors.

KVM Linodes are, by default, paravirtualized, supporting the Virtio disk and network drivers. However, we also now support fully virtualized guests – which means you can run alternative operating systems like FreeBSD, BSD, Plan 9, or even Windows – using emulated hardware (PIIX IDE and e1000). We’re also working on a graphical console (GISH?) which should be out in the next few weeks.

In a recent study of VM creation and SSH accessibility times performed by Cloud 66, Linode did well. The average Linode ‘create, boot, and SSH availability’ time was 57 seconds. KVM Linodes boot much faster – we’re seeing them take just a few seconds.

How do I upgrade a Linode from Xen to KVM?

On a Xen Linode’s dashboard, you will see an “Upgrade to KVM” link on the right sidebar. It’s a one-click migration to upgrade your Linode to KVM from there. Essentially, our KVM upgrade means you get a much faster Linode just by clicking a button.

How do I set my account to default to KVM for new stuff?

In your Account Settings you can set ‘Hypervisor Preference’ to KVM. After that, any new Linodes you create will be KVM.

What will happen to Xen Linodes?

New customers and new Linodes will, by default, still get Xen. Xen will cease being the default in the next few weeks. Eventually we will transition all Xen Linodes over to KVM, however this is likely to take quite a while. Don’t sweat it.

On behalf of the entire Linode team, thank you for the past 12 years and here’s to another 12! Enjoy!

-Chris

Filed under: upgrades, virtualization by caker

40 Responses

1. Alex June 16th, 2015 at 12:13 pm

Linode continues to be an excellent service provider. Thanks =)

2. Will June 16th, 2015 at 12:40 pm

You’re welcome Alex!

3. Dan June 16th, 2015 at 12:52 pm

My Linode continues to be a great value, and runs like a champ. Thanks for constantly improving and making the experience better and better.

4. rata June 16th, 2015 at 12:56 pm

Great news!

Some questions:

a) What is the result for the UnixBench testing a KVM 1024 Linode ? b) Is osv.io support planned ? c) Is live migration planned ?

5. caker June 16th, 2015 at 12:59 pm

@rata: 1) Don’t know, 2) No idea, probably? 3) Nope.

6. Alexander June 16th, 2015 at 1:03 pm

I choose Linode because of Xen

“Eventually we will transition all Xen Linodes over to KVM” – really hope you are not serious.

7. caker June 16th, 2015 at 1:06 pm

Dead serious.

8. HuarenKids June 16th, 2015 at 1:10 pm

Linode is AWSOME!

9. Ed June 16th, 2015 at 1:13 pm

Why was Xen used in the 1st place?

10. caker June 16th, 2015 at 1:16 pm

Ed: we used UML in the first place (2003). Neither Xen nor KVM existed. Then we moved to Xen. Now we’re moving to KVM.

11. Robson Sobral June 16th, 2015 at 1:18 pm

Hi! Great news! One question: How much downtime on upgrade?

12. Adam Zey June 16th, 2015 at 1:26 pm

A word of warning to customers: the KVM upgrade hosed my linode, and now it doesn’t boot. Be warned, this is not a seamless upgrade. I’m going to go open a trouble ticket.

13. Adam Zey June 16th, 2015 at 1:35 pm

A followup on my previous comment, it seems that Ubuntu on KVM requires that devtmpfs be enabled on your linode profile. Caker enabled it and now it’s booting fine.

Suggestion: this wasn’t required on Xen (or at least my linode booted fine before the upgrade), so perhaps the KVM upgrade should automatically enable it?

14. caker June 16th, 2015 at 1:49 pm

It’s required under Xen, too – however for reasons not yet understood Ubuntu was more tolerant to missing devtmpfs under Xen. We’re going to look at auto-enabling this during the upgrade. Thanks!

15. stefantalpalaru June 16th, 2015 at 1:50 pm

The downtime was 8-9 minutes for a 1GB instance (they have to copy the disk images to another host).

16. Professor Farnsworth June 16th, 2015 at 1:55 pm

Good news, everyone! ps: <3 Linode

17. Rick June 16th, 2015 at 2:47 pm

Thank you !

18. Amit June 16th, 2015 at 3:05 pm

Done! Done! Done! Done! Done! Done!

6 linodes migrated

19. Rich Russon June 16th, 2015 at 3:33 pm

Just upgraded my 2G Linode. Hmm… the cpu spec seems to have dropped:

Xen: model name : Intel(R) Xeon(R) CPU E5-2680 v2 @ 2.80GHz cpu MHz : 2800.044 bogomips : 5600.08

KVM: model name : Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz cpu MHz : 2499.994 bogomips : 5001.32

However, it’s running much more quickly.

The kernel build time dropped from 573 to 363 seconds. That’s 1.6x faster.

Many thanks Linode flatcap

20. Jeffrey Gelens June 16th, 2015 at 4:25 pm

Will you you also offer FreeBSD images in the future?

21. hnzz June 16th, 2015 at 4:25 pm

Ok, how to check /make sure devtmpfs is enabled on ububtu 14.04?

22. Simon Deziel June 16th, 2015 at 4:42 pm

We upgraded one of our VM that used pvgrub + OpenVZ kernel (2.6.32) and it didn’t boot. We were left at the “grub>” prompt.

Changing from paravirt to full virt made it work but I’m wondering if there is something we are missing?

23. Emil Vals June 16th, 2015 at 4:53 pm

Hmm can I run Windows Server now? I dont see the option.

24. Chris Jean June 16th, 2015 at 4:58 pm

Flawless upgrade and immediate performance gains. Thanks guys.

25. Paul June 16th, 2015 at 5:01 pm

Just migrated to KVM and cloudlinux os has stopped working. How can i install my own kernel?

26. Cogsmos Mike June 16th, 2015 at 5:09 pm

My Debian Jessie instance migrated seamlessly. It only took a few minutes.

27. Shyuan June 16th, 2015 at 5:37 pm

Finally! Thank you very much! I’m so gonna upgrade to KVM! Now everything is perfect <3

28. Adam Zey June 16th, 2015 at 6:35 pm

@Rich Russon: You’re missing the fact that your CPU changed from the E5-2680 v2 to the E5-2680 v3. The old one was a 10-core Ivy Bridge, the new one is a 12-core Haswell.

29. Micki June 16th, 2015 at 6:38 pm

Will there / is there any option for download host images and upload my own images?

30. Tim June 16th, 2015 at 6:58 pm

Would suggest proceeding with caution – I attempted a migration this morning, but it failed and now won’t boot at all. Support tells me that unfortunately a hardware issue occurred at exactly the time I attempted the migrate (despite no current hardware issues being shown on https://status.linode.com), and I’m still awaiting an update. I would have hoped the LVM migration script would perform a full health check so as to not leave customers stuck in limbo. The concept is great, but thus far I’m disappointed.

31. Joe June 16th, 2015 at 7:07 pm

Yay! I just migrated my server. It went great. My site feels much snappier. You guys rock! Thanks, Linode.

32. Matthew June 16th, 2015 at 7:09 pm

Would it possible to post a list of cpu flags supported in the new KVMs if different from the current Xen VMs (from /proc/cpuinfo)? I’m currently using aes instructions to accelerate ipsec on the Xen instance, but with KVM VMs aes isn’t always enabled.

33. Ricardo June 16th, 2015 at 7:19 pm

Do you support Nested KVM?

34. msg7086 June 16th, 2015 at 7:23 pm

HB Linode!

35. Tom June 16th, 2015 at 7:36 pm

Does this mean we can have LVM2 root drives?

Will we be able to use one Linode to build another (i.e., do an AWS- style chroot-build)?

36. caker June 16th, 2015 at 8:45 pm

@Micki: Yes. You can download your ‘image’ using Rescue Mode. You can upload your own image the exact same way (in reverse).

@Tim: you were coming from a troubled host, sadly. Looks like you’re sorted. Sorry for the hassle.

@Ricardo: it’s currently disabled. We left nesting off for the time being – but we will revisit this soon.

@Tom: you already could do LVM root. You have all the tools: GRUB, initrd, disk devices you can manage, etc. No?

37. Nathan June 16th, 2015 at 9:33 pm

Will we be able to install an OS straight from an ISO or will we still have to go through the old process to migrate it?

38. Denny June 16th, 2015 at 10:09 pm

Can you provide checklist for seamless migration? What I should doublecheck? For example, linode created /etc/fstab with “/dev/xvda” devices by default. Should I manually replace device names or not?

39. Ricardo June 16th, 2015 at 10:15 pm

Please consider enabling Nested KVM. We could host oVirt or OpenStack on top of it. Imagine that!

40. Stephen Reese June 17th, 2015 at 12:08 am

Already got FreeBSD running [1] and the Debian benchmark is an improvement [2].

[1] https://forum.linode.com/viewtopic.php?f=26&t=11818#p67319 [2] https://forum.linode.com/viewtopic.php?f=26&t=11851#p67217