Tag Archives: Edge Computing

Build your next big idea with Cloudflare Pages

Post Syndicated from Nevi Shah original https://blog.cloudflare.com/big-ideas-on-pages/

Build your next big idea with Cloudflare Pages

Build your next big idea with Cloudflare Pages

Have you ever had a surge of inspiration for a project? That feeling when you have a great idea – a big idea — that you just can’t shake? When all you can think about is putting your hands to your keyboard and hacking away? Building a website takes courage, creativity, passion and drive, and with Cloudflare Pages we believe nothing should stand in the way of that vision.

Especially not a price tag.

Big ideas

We built Pages to be at the center of your developer experience – a way for you to get started right away without worrying about the heavy lift of setting up a fullstack app.  A quick commit to your git provider or direct upload to our platform, and your rich and powerful site is deployed to our network of 270+ data centers in seconds. And above all, we built Pages to scale with you as you grow exponentially without getting hit by an unexpected bill.

The limit does not exist

We’re a platform that’s invested in your vision – no matter how wacky and wild (the best ones usually are!). That’s why for many parts of Pages we want your experience to be limitless.

Unlimited requests: As your idea grows, so does your traffic. While thousands and millions of end users flock to your site, Pages is prepared to handle all of your traffic with no extra cost to you – even when millions turn to billions.

Unlimited bandwidth: As your traffic grows, you’ll need more bandwidth – and with Pages, we got you. If your site takes off in popularity one day, the next day shouldn’t be a cause for panic because of a nasty bill. It should be a day of celebration and pride. We’re giving unlimited bandwidth so you can keep your eyes focused on moving up and to the right.

Unlimited free seats: With a rise in demand for your app, you’re going to need more folks working with you. We know from experience that more great ideas don’t just come from one person but a strong team of people. We want to be there every step of the way along with every person you want on this journey with you. Just because your team grows doesn’t mean your bill has to.

Unlimited projects: With one great idea, means many more to follow. With Pages, you can deploy as many projects as you want – keep them coming! Not every idea is going to be the right one – we know this! Prove out your vision in private org-owned repos for free! Try out a plethora of development frameworks until you’ve found the perfect combination for your idea. Test your changes locally using our Wrangler integration so you can be confident in whatever you choose to put out into the world.

Quick, easy and free integrations

Workers: Take your idea from static to dynamic with Pages’ native integration with Cloudflare Workers, our serverless functions offering. Drop your functions into your functions folder and deploy them alongside your static assets no extra configuration required! We announced built-in support for Cloudflare Workers back in November and have since announced framework integrations with Remix, Sveltekit and Qwik, and are working on fullstack support for Next.js within the year!

Cloudflare Access: Working with more than just a team of developers? Send your staging changes to product managers and marketing teams with a unique preview URL for every deployment. And what’s more? You can enable protection for your preview links using our native integration with Cloudflare Access at no additional cost. With one click, send around your latest version without fear of getting into the wrong hands.

Custom domains: With every Pages project, get a free pages.dev subdomain to deploy your project under. When you’re ready for the big day, with built in SSL for SaaS, bring that idea to life with a custom domain of its own!

Web Analytics: When launch day comes around, check out just how well it’s going with our deep, privacy-first integration with Cloudflare’s Web Analytics. Track every single one of your sites’ progress and performance, including metrics about your traffic and core web vitals with just one click – completely on us!

Wicked fast performance

And the best part? Our generous free tier never means compromising site performance. Bring your site closer to your users on your first deployment no matter where they are in the world. The Cloudflare network spans across 270+ cities around the globe and your site is distributed to each of them faster than you can say “it’s go time”. There’s also no need to choose regions for your deployments, we want you to have them all and get even more granular, so your big idea can truly go global.

What else?

Building on Pages is just the start of what your idea could grow to become. In the coming months you can expect deep integrations with our new Cloudflare storage offerings like R2, our object storage service with zero egress fees (open beta), and D1 our first SQL database on the edge (private beta).

We’ve talked a lot about building your entire platform on Cloudflare. We’re reimagining this experience to be even easier and even more powerful.

Using just Cloudflare, you’ll be able to build big projects – like an entire store! You can use R2 to host the images, D1 to store product info, inventory data and user details, and Pages to seamlessly build and deploy. A frictionless dev experience for a full stack app that can live and work entirely from the edge. Best of all, don’t worry about getting hung up on cost, we’ll always have a generous free tier so you can get started right away.

At Cloudflare, we believe that every developer deserves to dream big. For the developers who love to build, who are curious, who explore, let us take you there – no surprises! Leave the security and scalability to us, so you can put your fingers to the keyboard and do what you do best!

Give it a go

Learn more about Pages and check out our developer documentation. Be sure to join our active Cloudflare Developer Discord and meet our community of developers building on our platform. You can chat directly with our product and engineering teams and get exclusive access to our offered betas!

Building scheduling system with Workers and Durable Objects

Post Syndicated from Adam Janiš original https://blog.cloudflare.com/building-scheduling-system-with-workers-and-durable-objects/

Building scheduling system with Workers and Durable Objects

Building scheduling system with Workers and Durable Objects

We rely on technology to help us on a daily basis – if you are not good at keeping track of time, your calendar can remind you when it’s time to prepare for your next meeting. If you made a reservation at a really nice restaurant, you don’t want to miss it! You appreciate the app to remind you a day before your plans the next evening.

However, who tells the application when it’s the right time to send you a notification? For this, we generally rely on scheduled events. And when you are relying on them, you really want to make sure that they occur. Turns out, this can get difficult. The scheduler and storage backend need to be designed with scale in mind – otherwise you may hit limitations quickly.

Workers, Durable Objects, and Alarms are actually a perfect match for this type of workload. Thanks to the distributed architecture of Durable Objects and their storage, they are a reliable and scalable option. Each Durable Object has access to its own isolated storage and alarm scheduler, both being automatically replicated and failover in case of failures.

There are many use cases where having a reliable scheduler can come in handy: running a webhook service, sending emails to your customers a week after they sign up to keep them engaged, sending invoices reminders, and more!

Today, we’re going to show you how to build a scalable service that will schedule HTTP requests on a specific schedule or as one-off at a specific time as a way to guide you through any use case that requires scheduled events.

Building scheduling system with Workers and Durable Objects

Quick intro into the application stack

Before we dive in, here are some of the tools we’re going to be using today:

The application is going to have following components:

  • Scheduling system API to accept scheduled requests and manage Durable Objects
  • Unique Durable Object per scheduled request, each with
  • Storage – keeping the request metadata, such as URL, body, or headers.
  • Alarm – a timer (trigger) to wake Durable Object up.

While we will focus on building the application, the Cloudflare global network will take care of the rest – storing and replicating our data, and making sure to wake our Durable Objects up when the time’s right. Let’s build it!

Initialize new Workers project

Get started by generating a completely new Workers project using the wrangler init command, which makes creating new projects quick & easy.

wrangler init -y durable-objects-requests-scheduler

Building scheduling system with Workers and Durable Objects

For more information on how to install, authenticate, or update Wrangler, check out https://developers.cloudflare.com/workers/wrangler/get-started

Preparing TypeScript types

From my personal experience, at least a draft of TypeScript types significantly helps to be more productive down the road, so let’s prepare and describe our scheduled request in advance. Create a file types.ts in src directory and paste the following TypeScript definitions.


export interface Env {
    DO_REQUEST: DurableObjectNamespace
export interface ScheduledRequest {
  url: string // URL of the request
  triggerAt?: number // optional, unix timestamp in milliseconds, defaults to `new Date()`
  requestInit?: RequestInit // optional, includes method, headers, body

A scheduled request Durable Object class & alarm

Based on our architecture design, each scheduled request will be saved into its own Durable Object, effectively separating storage and alarms from each other and allowing our scheduling system to scale horizontally – there is no limit to the number of Durable Objects we create.

In the end, the Durable Object class is a matter of a couple of lines. The code snippet below accepts and saves the request body to a persistent storage and sets the alarm timer. Workers runtime will wake up the Durable Object and call the alarm() method to process the request.

The alarm method reads the scheduled request data from the storage, then processes the request, and in the end reschedules itself in case it’s configured to be executed on a recurring schedule.


import { ScheduledRequest } from "./types";
export class RequestDurableObject {
  id: string|DurableObjectId
  storage: DurableObjectStorage
  constructor(state:DurableObjectState) {
    this.storage = state.storage
    this.id = state.id
    async fetch(request:Request) {
    // read scheduled request from request body
    const scheduledRequest:ScheduledRequest = await request.json()
    // save scheduled request data to Durable Object storage, set the alarm, and return Durable Object id
    this.storage.put("request", scheduledRequest)
    this.storage.setAlarm(scheduledRequest.triggerAt || new Date())
    return new Response(JSON.stringify({
      id: this.id.toString()
    }), {
      headers: {
        "content-type": "application/json"
  async alarm() {
    // read the scheduled request from Durable Object storage
    const scheduledRequest:ScheduledRequest|undefined = await this.storage.get("request")
    // call fetch on scheduled request URL with optional requestInit
    if (scheduledRequest) {
      await fetch(scheduledRequest.url, scheduledRequest.requestInit ? webhook.requestInit : undefined)
      // cleanup scheduled request once done

Wrangler configuration

Once we have the Durable Object class, we need to create a Durable Object binding by instructing Wrangler where to find it and what the exported class name is.


name = "durable-objects-request-scheduler"
main = "src/index.ts"
compatibility_date = "2022-08-02"
# added Durable Objects configuration
bindings = [
  { name = "DO_REQUEST", class_name = "RequestDurableObject" },
tag = "v1"
new_classes = ["RequestDurableObject"]

Scheduling system API

The API Worker will accept POST HTTP methods only, and is expecting a JSON body with scheduled request data – what URL to call, optionally what method, headers, or body to send. Any other method than POST will return 405 – Method Not Allowed HTTP error.

HTTP POST /:scheduledRequestId? will create or override a scheduled request, where :scheduledRequestId is optional Durable Object ID returned from a scheduling system API before.


import { Env } from "./types"
export { RequestDurableObject } from "./request-durable-object"
export default {
    async fetch(
        request: Request,
        env: Env
    ): Promise<Response> {
        if (request.method !== "POST") {
            return new Response("Method Not Allowed", {status: 405})
        // parse the URL and get Durable Object ID from the URL
        const url = new URL(request.url)
        const idFromUrl = url.pathname.slice(1)
        // construct the Durable Object ID, use the ID from pathname or create a new unique id
        const doId = idFromUrl ? env.DO_REQUEST.idFromString(idFromUrl) : env.DO_REQUEST.newUniqueId()
        // get the Durable Object stub for our Durable Object instance
        const stub = env.DO_REQUEST.get(doId)
        // pass the request to Durable Object instance
        return stub.fetch(request)

It’s good to mention that the script above does not implement any listing of scheduled or processed webhooks. Depending on how the scheduling system would be integrated, you can save each created Durable Object ID to your existing backend, or write your own registry – using one of the Workers storage options.

Starting a local development server and testing our application

We are almost done! Before we publish our scheduler system to the Cloudflare edge, let’s start Wrangler in a completely local mode to run a couple of tests against it and to see it in action – which will work even without an Internet connection!

wrangler dev --local
Building scheduling system with Workers and Durable Objects

The development server is listening on localhost:8787, which we will use for scheduling our first request. The JSON request payload should match the TypeScript schema we defined in the beginning – required URL, and optional triggerEverySeconds number or triggerAt unix timestamp. When only the required URL is passed, the request will be dispatched right away.

An example of request payload that will send a GET request to https://example.com every 30 seconds.

	"url":  "https://example.com",
	"triggerEverySeconds": 30,
> curl -X POST -d '{"url": "https://example.com", "triggerEverySeconds": 30}' http://localhost:8787
Building scheduling system with Workers and Durable Objects

From the wrangler logs we can see the scheduled request ID 000000018265a5ecaa5d3c0ab6a6997bf5638fdcb1a8364b269bd2169f022b0f is being triggered in 30s intervals.

Need to double the interval? No problem, just send a new POST request and pass the request ID as a pathname.

> curl -X POST -d '{"url": "https://example.com", "triggerEverySeconds": 60}' http://localhost:8787/000000018265a5ecaa5d3c0ab6a6997bf5638fdcb1a8364b269bd2169f022b0f

Every scheduled request gets a unique Durable Object ID with its own storage and alarm. As we demonstrated, the ID becomes handy when you need to change the settings of the scheduled request, or to deschedule them completely.

Publishing to the network

Following command will bundle our Workers application, export and bind Durable Objects, and deploy it to our workers.dev subdomain.

wrangler publish
Building scheduling system with Workers and Durable Objects

That’s it, we are live! 🎉 The URL of your deployment is shown in the Workers logs. In a reasonably short period of time we managed to write our own scheduling system that is ready to handle requests at scale.

You can check full source code in Workers templates repository, or experiment from your browser without installing any dependencies locally using the StackBlitz template.

What to see or build next

An introduction to three-phase power and PDUs

Post Syndicated from Rob Dinh original https://blog.cloudflare.com/an-introduction-to-three-phase-power-and-pdus/

An introduction to three-phase power and PDUs

Our fleet of over 200 locations comprises various generations of servers and routers. And with the ever changing landscape of services and computing demands, it’s imperative that we manage power in our data centers right. This blog is a brief Electrical Engineering 101 session going over specifically how power distribution units (PDU) work, along with some good practices on how we use them. It appears to me that we could all use a bit more knowledge on this topic, and more love and appreciation of something that’s critical but usually taken for granted, like hot showers and opposable thumbs.

A PDU is a device used in data centers to distribute power to multiple rack-mounted machines. It’s an industrial grade power strip typically designed to power an average consumption of about seven US households. Advanced models have monitoring features and can be accessed via SSH or webGUI to turn on and off power outlets. How we choose a PDU depends on what country the data center is and what it provides in terms of voltage, phase, and plug type.

An introduction to three-phase power and PDUs

For each of our racks, all of our dual power-supply (PSU) servers are cabled to one of the two vertically mounted PDUs. As shown in the picture above, one PDU feeds a server’s PSU via a red cable, and the other PDU feeds that server’s other PSU via a blue cable. This is to ensure we have power redundancy maximizing our service uptime; in case one of the PDUs or server PSUs fail, the redundant power feed will be available keeping the server alive.

Faraday’s Law and Ohm’s Law

Like most high-voltage applications, PDUs and servers are designed to use AC power. Meaning voltage and current aren’t constant — they’re sine waves with magnitudes that can alternate between positive and negative at a certain frequency. For example, a voltage feed of 100V is not constantly at 100V, but it bounces between 100V and -100V like a sine wave. One complete sine wave cycle is one phase of 360 degrees, and running at 50Hz means there are 50 cycles per second.

The sine wave can be explained by Faraday’s Law and by looking at how an AC power generator works. Faraday’s Law tells us that a current is induced to flow due to a changing magnetic field. Below illustrates a simple generator with a permanent magnet rotating at constant speed and a coil coming in contact with the magnet’s magnetic field. Magnetic force is strongest at the North and South ends of the magnet. So as it rotates on itself near the coil, current flow fluctuates in the coil. One complete rotation of the magnet represents one phase. As the North end approaches the coil, current increases from zero. Once the North end leaves, current decreases to zero. The South end in turn approaches, now the current “increases” in the opposite direction. And finishing the phase, the South end leaves returning the current back to zero. Current alternates its direction at every half cycle, hence the naming of Alternating Current.

An introduction to three-phase power and PDUs

Current and voltage in AC power fluctuate in-phase, or “in tandem”, with each other. So by Ohm’s Law of Power = Voltage x Current, power will always be positive. Notice on the graph below that AC power (Watts) has two peaks per cycle. But for practical purposes, we’d like to use a constant power value. We do that by interpreting AC power into “DC” power using root-mean-square (RMS) averaging, which takes the max value and divides it by √2. For example, in the US, our conditions are 208V 24A at 60Hz. When we look at spec sheets, all of these values can be assumed as RMS’d into their constant DC equivalent values. When we say we’re fully utilizing a PDU’s max capacity of 5kW, it actually means that the power consumption of our machines bounces between 0 and 7.1kW (5kW x √2).

An introduction to three-phase power and PDUs
An introduction to three-phase power and PDUs

It’s also critical to figure out the sum of power our servers will need in a rack so that it falls under the PDU’s design max power capacity. For our US example, a PDU is typically 5kW (208 volts x 24 amps); therefore, we’re budgeting 5kW and fit as many machines as we can under that. If we need more machines and the total sum power goes above 5kW, we’d need to provision another power source. That would lead to possibly another set of PDUs and racks that we may not fully use depending on demand; e.g. more underutilized costs. All we can do is abide by P = V x I.

However there is a way we can increase the max power capacity economically — 3-phase PDU. Compared to single phase, its max capacity is √3 or 1.7 times higher. A 3-phase PDU of the same US specs above has a capacity of 8.6kW (5kW x √3), allowing us to power more machines under the same source. Using a 3-phase setup might mean it has thicker cables and bigger plug; but despite being more expensive than a 1-phase, its value is higher compared to two 1-phase rack setups for these reasons:

  • It’s more cost-effective, because there are fewer hardware resources to buy
  • Say the computing demand adds up to 215kW of hardware, we would need 25 3-phase racks compared to 43 1-phase racks.
  • Each rack needs two PDUs for power redundancy. Using the example above, we would need 50 3-phase PDUs compared to 86 1-phase PDUs to power 215kW worth of hardware.
  • That also means a smaller rack footprint and fewer power sources provided and charged by the data center, saving us up to √3 or 1.7 times in opex.
  • It’s more resilient, because there are more circuit breakers in a 3-phase PDU — one more than in a 1-phase. For example, a 48-outlet PDU that is 1-phase would be split into two circuits of 24 outlets. While a 3-phase one would be split into 3 circuits of 16 outlets. If a breaker tripped, we’d lose 16 outlets using a 3-phase PDU instead of 24.
An introduction to three-phase power and PDUs

The PDU shown above is a 3-phase model of 48 outlets. We can see three pairs of circuit breakers for the three branches that are intertwined with each other white, grey, and black. Industry demands today pressure engineers to maximize compute performance and minimize physical footprint, making the 3-phase PDU a widely-used part of operating a data center.

What is 3-phase?

A 3-phase AC generator has three coils instead of one where the coils are 120 degrees apart inside the cylindrical core, as shown in the figure below. Just like the 1-phase generator, current flow is induced by the rotation of the magnet thus creating power from each coil sequentially at every one-third of the magnet’s rotation cycle. In other words, we’re generating three 1-phase power offset by 120 degrees.

An introduction to three-phase power and PDUs

A 3-phase feed is set up by joining any of its three coils into line pairs. L1, L2, and L3 coils are live wires with each on their own phase carrying their own phase voltage and phase current. Two phases joining together form one line carrying a common line voltage and line current. L1 and L2 phase voltages create the L1/L2 line voltage. L2 and L3 phase voltages create the L2/L3 line voltage. L1 and L3 phase voltages create the L1/L3 line voltage.

An introduction to three-phase power and PDUs

Let’s take a moment to clarify the terminology. Some other sources may refer to line voltage (or current) as line-to-line or phase-to-phase voltage (or current). It can get confusing, because line voltage is the same as phase voltage in 1-phase circuits, as there’s only one phase. Also, the magnitude of the line voltage is equal to the magnitude of the phase voltage in 3-phase Delta circuits, while the magnitude of the line current is equal to the magnitude of the phase current in 3-phase Wye circuits.

Conversely, the line current equals to phase current times √3 in Delta circuits. In Wye circuits, the line voltage equals to phase voltage times √3.

In Delta circuits:
Vline = Vphase
Iline = √3 x Iphase

In Wye circuits:
Vline = √3 x Vphase
Iline = Iphase

Delta and Wye circuits are the two methods that three wires can join together. This happens both at the power source with three coils and at the PDU end with three branches of outlets. Note that the generator and the PDU don’t need to match each other’s circuit types.

An introduction to three-phase power and PDUs

On PDUs, these phases join when we plug servers into the outlets. So we conceptually use the wirings of coils above and replace them with resistors to represent servers. Below is a simplified wiring diagram of a 3-phase Delta PDU showing the three line pairs as three modular branches. Each branch carries two phase currents and its own one common voltage drop.

An introduction to three-phase power and PDUs

And this one below is of a 3-phase Wye PDU. Note that Wye circuits have an additional line known as the neutral line where all three phases meet at one point. Here each branch carries one phase and a neutral line, therefore one common current. The neutral line isn’t considered as one of the phases.

An introduction to three-phase power and PDUs

Thanks to a neutral line, a Wye PDU can offer a second voltage source that is √3 times lower for smaller devices, like laptops or monitors. Common voltages for Wye PDUs are 230V/400V or 120V/208V, particularly in North America.

Where does the √3 come from?

Why are we multiplying by √3? As the name implies, we are adding phasors. Phasors are complex numbers representing sine wave functions. Adding phasors is like adding vectors. Say your GPS tells you to walk 1 mile East (vector a), then walk a 1 mile North (vector b). You walked 2 miles, but you only moved by 1.4 miles NE from the original location (vector a+b). That 1.4 miles of “work” is what we want.

Let’s take in our application L1 and L2 in a Delta circuit. we add phases L1 and L2, we get a L1/L2 line. We assume the 2 coils are identical. Let’s say α represents the voltage magnitude for each phase. The 2 phases are 120 degrees offset as designed in the 3-phase power generator:

|L1| = |L2| = α
L1 = |L1|∠0° = α∠0°
L2 = |L2|∠-120° = α∠-120°

Using vector addition to solve for L1/L2:

L1/L2 = L1 + L2

An introduction to three-phase power and PDUs
An introduction to three-phase power and PDUs

Convert L1/L2 into polar form:

An introduction to three-phase power and PDUs

Since voltage is a scalar, we’re only interested in the “work”:

|L1/L2| = √3α

Given that α also applies for L3. This means for any of the three line pairs, we multiply the phase voltage by √3 to calculate the line voltage.

Vline = √3 x Vphase

Now with the three line powers being equal, we can add them all to get the overall effective power. The derivation below works for both Delta and Wye circuits.

Poverall = 3 x Pline
Poverall = 3 x (Vline x Iline)
Poverall = (3/√3) x (Vphase x Iphase)
Poverall = √3 x Vphase x Iphase

Using the US example, Vphase is 208V and Iphase is 24A. This leads to the overall 3-phase power to be 8646W (√3 x 208V x 24A) or 8.6kW. There lies the biggest advantage for using 3-phase systems. Adding 2 sets of coils and wires (ignoring the neutral wire), we’ve turned a generator that can produce √3 or 1.7 times more power!

Dealing with 3-phase

The derivation in the section above assumes that the magnitude at all three phases is equal, but we know in practice that’s not always the case. In fact, it’s barely ever. We rarely have servers and switches evenly distributed across all three branches on a PDU. Each machine may have different loads and different specs, so power could be wildly different, potentially causing a dramatic phase imbalance. Having a heavily imbalanced setup could potentially hinder the PDU’s available capacity.

A perfectly balanced and fully utilized PDU at 8.6kW means that each of its three branches has 2.88kW of power consumed by machines. Laid out simply, it’s spread 2.88 + 2.88 + 2.88. This is the best case scenario. If we were to take 1kW worth of machines out of one branch, spreading power to 2.88 + 1.88 + 2.88. Imbalance is introduced, the PDU is underutilized, but we’re fine. However, if we were to put back that 1kW into another branch — like 3.88 + 1.88 + 2.88 — the PDU is over capacity, even though the sum is still 8.6kW. In fact, it would be over capacity even if you just added 500W instead of 1kW on the wrong branch, thus reaching 3.18 + 1.88 + 2.88 (8.1kW).

That’s because a 8.6kW PDU is spec’d to have a maximum of 24A for each phase current. Overloading one of the branches can force phase currents to go over 24A. Theoretically, we can reach the PDU’s capacity by loading one branch until its current reaches 24A and leave the other two branches unused. That’ll render it into a 1-phase PDU, losing the benefit of the √3 multiplier. In reality, the branch would have fuses rated less than 24A (usually 20A) to ensure we won’t reach that high and cause overcurrent issues. Therefore the same 8.6kW PDU would have one of its branches tripped at 4.2kW (208V x 20A).

Loading up one branch is the easiest way to overload the PDU. Being heavily imbalanced significantly lowers PDU capacity and increases risk of failure. To help minimize that, we must:

  • Ensure that total power consumption of all machines is under the PDU’s max power capacity
  • Try to be as phase-balanced as possible by spreading cabling evenly across the three branches
  • Ensure that the sum of phase currents from powered machines at each branch is under the fuse rating at the circuit breaker.

This spreadsheet from Raritan is very useful when designing racks.

For the sake of simplicity, let’s ignore other machines like switches. Our latest 2U4N servers are rated at 1800W. That means we can only fit a maximum of four of these 2U4N chassis (8600W / 1800W = 4.7 chassis). Rounding them up to 5 would reach a total rack level power consumption of 9kW, so that’s a no-no.

Splitting 4 chassis into 3 branches evenly is impossible, and will force us to have one of the branches to have 2 chassis. That would lead to a non-ideal phase balancing:

An introduction to three-phase power and PDUs

Keeping phase currents under 24A, there’s only 1.1A (24A – 22.9A) to add on L1 or L2 before the PDU gets overloaded. Say we want to add as many machines as we can under the PDU’s power capacity. One solution is we can add up to 242W on the L1/L2 branch until both L1 and L2 currents reach their 24A limit.

An introduction to three-phase power and PDUs

Alternatively, we can add up to 298W on the L2/L3 branch until L2 current reaches 24A. Note we can also add another 298W on the L3/L1 branch until L1 current reaches 24A.

An introduction to three-phase power and PDUs

In the examples above, we can see that various solutions are possible. Adding two 298W machines each at L2/L3 and L3/L1 is the most phase balanced solution, given the parameters. Nonetheless, PDU capacity isn’t optimized at 7.8kW.

Dealing with a 1800W server is not ideal, because whichever branch we choose to power one would significantly swing the phase balance unfavorably. Thankfully, our Gen X servers take up less space and are more power efficient. Smaller footprint allows us to have more flexibility and fine-grained control over our racks in many of our diverse data centers. Assuming each 1U server is 450W, as if we physically split the 1800W 2U4N into fours each with their own power supplies, we’re now able to fit 18 nodes. That’s 2 more nodes than the four 2U4N setup:

An introduction to three-phase power and PDUs

Adding two more servers here means we’ve increased our value by 12.5%. While there are more factors not considered here to calculate the Total Cost of Ownership, this is still a great way to show we can be smarter with asset costs.

Cloudflare provides the back-end services so that our customers can enjoy the performance, reliability, security, and global scale of our edge network. Meanwhile, we manage all of our hardware in over 100 countries with various power standards and compliances, and ensure that our physical infrastructure is as reliable as it can be.

There’s no Cloudflare without hardware, and there’s no Cloudflare without power. Want to know more? Watch this Cloudflare TV segment about power: https://cloudflare.tv/event/7E359EDpCZ6mHahMYjEgQl.

Creating an EC2 instance in the AWS Wavelength Zone

Post Syndicated from Bala Thekkedath original https://aws.amazon.com/blogs/compute/creating-an-ec2-instance-in-the-aws-wavelength-zone/

Creating an EC2 instance in the AWS Wavelength Zone

This blog post is contributed by Saravanan Shanmugam, Lead Solution Architect, AWS Wavelength

AWS announced Wavelength at re:Invent 2019 in partnership with Verizon in US, SK Telecom in South Korea, KDDI in Japan, and Vodafone in UK and Europe. Following the re:Invent 2019 announcement, on August 6, 2020, AWS announced GA of one Wavelength Zone with Verizon in Boston connected to US East (N.Virginia) Region and one in San Francisco connected to the US West (Oregon) Region.

In this blog, I walk you through the steps required to create an Amazon EC2 instance in an AWS Wavelength Zone from the AWS Management console. We also address the questions asked by our customers regarding the different protocol traffic allowed into and out of a AWS Wavelength Zones.

Customers who want to access AWS Wavelength Zones and deploy their applications to the Wavelength Zone can sign up using this link. Customers that opted in to access the AWS Wavelength Zone can confirm the status on the EC2 console Account Attribute section as shown in the following image.

 Services and features

AWS Wavelength Zones are Availability Zones inside the Carrier Service Provider network closer to the Edge of the Mobile Network. Wavelength Zones bring the AWS core compute and storage services like Amazon EC2 and Amazon EBS that can be used by other services like Amazon EKS and Amazon ECS. We look at Wavelength Zone(s) as a hub and spoke model, where developers can deploy latency sensitive, high-bandwidth applications at the Edge and non-latency sensitive and data persistent applications in the Region.

Wavelength Zones supports three Nitro based Amazon EC2 instance types t3 (t3.medium, t3.xlarge) r5 (r5.2xlarge) and g4 (g4dn.2xlarge) with EBS volume types gp2. Customers can also use Amazon ECS and Amazon EKS to deploy container applications at the Edge. Other AWS Services, like AWS CloudFormation templates, CloudWatch, IAM resources, and Organizations, continue to work as expected, providing you a consistent experience. You can also leverage the full suite of services like Amazon S3 in the parent Region over AWS’s private network backbone. Now that we have reviewed AWS wavelength, the services and features associated with it, let us talk about the steps to launch an EC2 instance in the AWS Wavelength zone.

Creating a Subnet in the Wavelength Zone

Once the Wavelength Zone is enabled for your AWS Account, you can extend your existing VPC from the parent Region to a Wavelength Zone by creating a new VPC subnet assigned to the AWS Wavelength Zone. Customers can also create a new VPC and then a Subnet to deploy their applications in the Wavelength zone. The following image shows the Subnet creation step, where you pick the Wavelength Zone as the Availability zone for the subnet

Carrier Gateway

We have introduced a new gateway type called Carrier Gateway, which allows you to route traffic from the Wavelength Zone subnet to the CSP network and to the Internet. Carrier Gateways are similar to the Internet gateway in the Region. Carrier Gateway is also responsible for NAT’ing the traffic from/to the Wavelength Zone subnets mapping it to the carrier ip address assigned to the instances.

Creating a Carrier Gateway

In the VPC console, you can now create Carrier Gateway and attach it to your VPC.

You select the VPC to which the Carrier Gateway must be attached. There is also option to select “Route subnet traffic to the Carrier Gateway” in the Carrier Gateway creation step. By selecting this option, you can pick the Wavelength subnets you want to default route to the Carrier Gateway. This option automatically deletes the existing route table to the subnets, creates a new route table, creates a default route entry, and attaches the new route table to the Subnets you selected. The following picture captures the necessary input required while creating a Carrier Gateway


Creating an EC2 instance in a Wavelength Zone with Private IP Address

Once a VPC subnet is created for the AWS Wavelength Zone, you can launch an EC2 instance with a Private address using the EC2 Launch Wizard. In the configure instance details step, you can select the Wavelength Zone Subnet that you created in the “Creating a Subnet” section.

Attach a IAM profile with SSM role included, which allows you to SSH into the console of the instance through SSM. This is a recommended practice for Wavelength Zone instances as there is no direct SSH access allowed from Public internet.

 Creating an EC2 instance in a Wavelength Zone with Carrier IP Address

The instances running in the Wavelength Zone subnets can obtain a Carrier IP address, which is allocated from a pool of IP addresses called Network Border group (NBG). To create an EC2 instance in the Wavelength Zone with a carrier routable IP address, you can use AWS CLI. You can use the following command to create EC2 instance in a Wavelength Zone subnet. Note the additional network interface (NIC) option “AssociateCarrierIpAddress: as part of the EC2 run instance command, as shown in the following command.

aws ec2 --region us-west-2 run-instances --network-interfaces '[{"DeviceIndex":0, "AssociateCarrierIpAddress": true, "SubnetId": "<subnet-0d3c2c317ac4a262a>"}]' --image-id <ami-0a07be880014c7b8e> --instance-type t3.medium --key-name <san-francisco-wavelength-sample-key>

 *To use “AssociateCarrierIpAddress” option in the ec2 run-instance command use the latest aws cli v2.

The carrier IP assigned to the EC2 instance can be obtained by running the following command.

 aws ec2 describe-instances --instance-ids <replace-with-your-instance-id> --region us-west-2

 Make necessary changes to the default security group that is attached to the EC2 instance after running the run-instance command to allow the necessary protocol traffic. If you allow ICMP traffic to your EC2 instance, you can test ICMP connectivity to your instance from the public internet.

The different protocols allowed in and out of the Wavelength Zone are captured in the following table.


TCP Connection FROM TCP Connection TO Result*
Region Zones WL Zones Allowed
Wavelength Zones Region Allowed
Wavelength Zones Internet Allowed
Internet (TCP SYN) WL Zones Blocked
Internet (TCP EST) WL Zones Allowed
Wavelength Zones UE (Radio) Allowed
UE(Radio) WL Zones Allowed


UDP Packets FROM UDP Packets TO Result*
Wavelength Zones WL Zones Allowed
Wavelength Zones Region Allowed
Wavelength Zones Internet Allowed
Internet WL Blocked
Wavelength Zones UE (Radio) Allowed
UE(Radio) WL Zones Allowed


Wavelength Zones WL Zones Allowed
Wavelength Zones Region Allowed
Wavelength Zones Internet Allowed
Internet WL Allowed
Wavelength Zones UE (Radio) Allowed
UE(Radio) WL Zones Allowed


We have covered how to create and run an EC2 instance in the AWS Wavelength Zone, the core foundation for application deployments. We will continue to publish blogs helping customers to create ECS and EKS clusters in the AWS Wavelength Zones and deploy container applications at the Mobile Carriers Edge. We are really looking forward to seeing what all you can do with them. AWS would love to get your advice on additional local services/features or other interesting use cases, so feel free to leave us your comments!