Migrating From AWS to FB

http://instagram-engineering.tumblr.com/post/89992572022/migrating-aws-fb

by dctrwatson • 12 years ago

303 91 12 years ago

instagram-engineering.tumblr.com

0x006A2• 12 years ago

why not just create a vpn between the nodes with another private IP space and send your data through that?

cbhl• 12 years ago

Perhaps that would become a bottleneck at Instagram's scale?

blackaspen2• 12 years ago

I believe it becomes a bottleneck at the scale of like, 5 servers.

This is a tough problem, Neti is a heck of a lot better than tons of VPN connections everywhere.

toomuchtodo2• 12 years ago

"This task looked incredibly daunting on the face of it; we were running many thousands of instances in EC2, with new ones spinning up every day. In order to minimize downtime and operational complexity, it was essential that instances running in both EC2 and VPC seemed as if they were part of the same network. AWS does not provide a way of sharing security groups nor bridging private EC2 and VPC networks. The only way to communicate between the two private networks is to use the public address space."

That is essentially what Neti does, except instead of static mappings, its dynamic and software configurable (which is pretty much the only way to go when you're entire environment is virtual and the underlying network equipment is out of your control).

0x006A2• 12 years ago

Using a VPN would still be an option. Why write essentially your own VPN (neti) instead of using an existing VPN solution? VPC is not the only VPN you can use on EC2.

Rapzid• 12 years ago

So I guess it was a bit of hyperbole. A straight forward solution to a straight forward problem.

agwa7• 12 years ago

The main blocker to this easy migration was that Facebook’s private IP space conflicts with that of EC2

IPv6 adoption could not happen soon enough.

cheald• 12 years ago

I think it has more to do with the fact that there are a standard series of private IP blocks.

rdl• 12 years ago

Right, but if everyone used IPv6 there would be no need to use non-routeable private IPs for anything, you could just use non-conflicting IPv6 addresses and not route them.

nitinics• 12 years ago

You can always create multiple routing instances (namespaces) for overlapping IPv4 blocks with a VRF-based strategy. This would create separate FIBs and IMHO is a cleaner approach than mangling packets with iptables.

justincormack• 12 years ago

Facebook supports ipv6, but maybe it is external only? I know Google is ipv6 internally too. Although as EC2 has no ipv6 maybe that was the blocking issue.

agwa7• 12 years ago

Facebook makes extensive use of IPv6 internally. As you suggested, EC2's lack of support is the issue.

Edit: here are the slides from Facebook's presentation to the IPv6 World Congress in March about their internal IPv6 use. If IPv6 interests you, they're definitely worth a read: http://www.internetsociety.org/deploy360/wp-content/uploads/...

deftnerd• 12 years ago

You can reach Facebook over IPv6 at https://www.v6.facebook.com

Interestingly enough, last week when they had their 45 minute outage worldwide with some kind of routing problem, it was still up and running on that address

DmitriRavinoff• 12 years ago

An EC2 rep has told me on more than one occasion that they have no plans to support ipv6 because the demand for it simply isn't there.

giovannibajo12• 12 years ago

That's because people don't realize how useful it is in network ops because they re not used to it. This thread is an example were a glaring advantage of ipv6 wasn't immediately obvious.

Anybody who ever tried the VPC+ElasticIP+VPN braindeadness once should immediately file a feature request for ipv6; it's just that they don't probably think of it

rbranson3• 12 years ago

Agree in principle, but it's unlikely for Amazon to ever force customers to allocate addresses from their own IPv6 block to begin with. Like many other startups, Instagram started with the bare-minimum setup outside of VPC, and scaled from there, not even knowing the benefits of VPC before it was too late for a simple cutover.

agwa7• 12 years ago

Amazon doesn't have to force customers to use their own IPv6 blocks. EC2 instances, whether inside or outside VPC, would be assigned unique IPv6 addresses from Amazon's address space (which would be extensive). If this were the norm when Instagram started out, it would have been just as easy to use, and there would have been no clash of addresses when migrating to Facebook.

meritt• 12 years ago

Is neti open-source?

kawsper• 12 years ago

Managing iptables across datacenters and nodes would be a fun project to do with something like Serf (http://www.serfdom.io/)

fintler• 12 years ago

At the Velocity talk today, he said they're going to make it open source.

maceip2• 12 years ago

"Facebook’s private IP space conflicts with that of EC2"

^ That wouldn't've happened in GCE (i.e., they should have been acquired by Google).

cheeseprocedure2• 12 years ago

Are you sure? This document suggests GCE instances use the 10.x.x.x address space (just as AWS instances in EC2 Classic do):

https://developers.google.com/compute/docs/instances-and-net...

maceip2• 12 years ago

""" Although Compute Engine doesn't allow creating an instance with a user-defined local IP address, you can use a combination of routes and an instance's ‑‑can_ip_forward ability to add local IP address as a network static address which then maps to your desired virtual machine instance.

For example, if you want to assign 10.1.1.1 specifically as a network address to a virtual machine instance, you can create a static network route that sends traffic from 10.1.1.1 to your instance, even if the instance's network address assigned by Compute Engine doesn't match your desired network address. """

Meaning they could have avoided conflicts using this mechanism.

aristus• 12 years ago

Called it, five years ago: http://www.web2expo.com/webexny2009/public/schedule/detail/9...

Run in multiple clouds from day one. Take the pain. It gives you flexibility. Basic vendor management 101.

serge2k• 12 years ago

This article mentions nothing about latency.

sumbry• 12 years ago

We're undertaking a similar project and the latency is almost negligible. In fact the latency is lower bridging between classic and vpc in the same availability zone than between two classic availability zones.

rhoml2• 12 years ago

They mentioned AWS direct connect which helps to reduce latency.

codeka2• 12 years ago

Maybe it's worth the pain if every startup became the size of Instagram and got bought by Facebook, but that's only true for a tiny, tiny fraction of a % of all startups.

davidw• 12 years ago

Yes - truth be told, I am not sure if there's much to take away from this article if you're not really aiming for something huge. And even then, maybe you should spend time on what'll get you traction rather than trying to design an architecture for what you hope to become. Instagram is very much an outlier.

conorgil145• 12 years ago

Run in multiple clouds from day one. Take the pain. It gives you flexibility. Basic vendor management 101.

While "taking the pain" may yield flexibility in the long run, the most important thing in the short run is making sure that you are building something that people want, listening to users, and iterating the tech side of things as quickly as possible. I suspect that most devs have enough trouble dealing with a single cloud provider and that trying to work with multiple would could a significant decrease in iteration speed. I think that approach would kill most startups because of the technical overhead incurred.

jordo37• 12 years ago

This seems like exactly the sort of advice that is great in retrospect once you reach scale but is effectively useless until you hit that point. There are far more important things for a startup to worry about (product market fit, retention, stability) than how to make the tech side of an acquisition easy.

EGreg• 12 years ago

These engineering feats are truly impressive and worth writing about.

And yet every time I read about this kind of stuff I think, how glad am I that we are building a DISTRIBUTED social network and will never have to solve problems on this massive scale! We won't have to move millions of other people's photos here or there if everything is distributed from day 1. People will be able to move their own stuff easily wherever they want.

tomphoolery• 12 years ago

Has Facebook ever been public about the tools they use for deploying new machines onto bare metal with Chef? My company faces similar problems, albeit at a much smaller scale, but still...I'm wondering what they have in place of a tool such as http://theforeman.org (which is very coupled to Puppet).

rhoml2• 12 years ago

I think they just said this https://www.youtube.com/watch?v=SYZ2GzYAw_Q

bmetz• 12 years ago

And those "numerous integration points" are?

mikeyk2• 12 years ago

Mike from IG here. Some early wins are integrations with spam fighting systems, logging infrastructure, and FB's Hive infrastructure.

NathanKP• 12 years ago

I wonder why Instagram wasn't using VPC in the first place. I've been using AWS for a startup for a few years now and I had our instances running in VPC from about the second month onward.

It's been one of the best architecture decisions I've ever made. At this point we only use one public IP address. (If direct access to a machine is needed then you can connect via VPN running on the one bastion host with the public IP address, and this gives your machine access to the local IP addresses of instances running inside the VPC.)

All the machines in our cluster are protected inside local VPC address space, with the access by the external world being ELB to expose public service endpoints like the API and website. I can't think of any good reason why you wouldn't be using VPC in the first place. Having public IP addresses for private machines sounds like a recipe for disaster if you ever accidentally miss a port in your security rules.

mikeyk2• 12 years ago

Mike from IG here. VPC was barely a thing when we got on AWS (2010) and at the time not the default. I would definitely have done VPC from day 1 in hindsight, though.

blackaspen2• 12 years ago

Hindsight is 20/20.

I think you guys did an exceptional job to tackling a really difficult problem (I've been in the same position, migrating EC2 to Datacenters) and we determined that EC2 -> VPC -> Datacenters is really the only way, and Neti solves it surprisingly well.

Going forward, hope that acquired companies opened their AWS accounts late enough that Amazon forced them to use VPC.

jmccree• 12 years ago

If you assume they had no pressing need for any VPC specific functionality, you can get similar security by locking your security group/s down to only ELB for public service ports and having one instance in another security group with ssh/vpn allowed (to specific ips) as a jump box/vpn. Spending weeks of multiple teams engineering time to move to VPC without a pressing need would seem to me to make little business sense.

purephase• 12 years ago

Agreed. This is the route I use and it works fine. I can see how it could quickly get out of hand with a lot of security groups, and I would love some sort of security group inheritance, but for -100 instances, it is not the hard to keep the public access to ELB.

general_failure• 12 years ago

Any reason not to choose docker over lxc? Is it because fb data centers are already lxc friendly?

nbm• 12 years ago

The existing Facebook deployment system supports running deployments within an LXC (and setting up cgroups, &c.) and was written well before docker was available.

Some background:

* http://www.slideshare.net/dotCloud/tupperware-containerized-...

SushiMon2• 12 years ago

I'm wondering if they got nailed by out-migration charges and how much that was. I assume a bunch of their images were in S3. Amazon charges a pretty penny to take things out.

ceejayoz3• 12 years ago

I'm confused by this. S3 GET requests are the cheapest request type, and getting the images out would just cost you the bandwidth involved.

Maybe you're mixing things up with Glacier?

SushiMon2• 12 years ago

GET Requests are cheap But I was thinking of bandwidth costs to get things out of S3 entirely and do a complete outmigration. But the prices there have come down quite a bit since I last checked.

evan_• 12 years ago

They could have used the export service:

http://aws.amazon.com/importexport/

shiftb• 12 years ago

I got an error page inside the Instagram mobile app a few days ago and was surprised to see Facebook server chrome around the error message.

I'm impressed out how fast they got this migration done, considering how massive the scale they operate at is.

yeukhon• 12 years ago

Contributors? What contributors? People from within the company or open source contributors?

blakesmith• 12 years ago

It's usually the stateful stuff that proves challenging in big datacenter moves, but I don't see any mention of data copying, replication, or moving. How did you guys tackle the problems of keeping data in sync and doing a clean cutover?

mkfifo• 12 years ago

and now Instagram can share ALL of its data with the US gov too.

ch• 12 years ago

I think this is the biggest takeaway from the article:

Plan to change just the bare minimum needed to support the new environment, and avoid the temptation of “while we’re here.”

Good engineering is knowing how to act with surgical precision when necessary. This is what allows a craft like programming to operate in the confines of a business.

cooltrance• 12 years ago

It is amazing how a post like this could reach the front page of hacker news just because it comes from Instagram rather than for its technical relevance.

They mentioned Neti but didn't dig into details other than "a dynamic iptables manipulation daemon, written in Python, and backed by ZooKeeper." and they mentioned the ip blocker which is an issue on almost every migration.

Also taking into consideration that they didn't write a post in the past 10 months, I am sure that they can do it better.

Migrating From AWS to FB

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