Browsed by
Category: English

Going Cloud: the 8 don’ts

Going Cloud: the 8 don’ts

Okay, let’s face it: the world is figuring out that cloud is for everyone, and not just for large-scale enterprises. This is a big step ahead, but when it comes to smaller companies there are still many misconceptions and wrong expectations.

Wrong expectations are the main push back reason, because they usually lead to catastrophic failures and disasters that leave migrating back to a legacy infrastructure design as the only option left.


(Image Source: XKCD)

But, comes out, it’s easier than you would expect. There is a basic set of rules and guidelines, and if you follow them then there is a 99.99% change you will be successful.

Let’s start today with the 8 don’ts.

  1. Never, ever trust a single hosted service. Don’t rely on redundant database platforms, replicated block devices, and many more. They can still go down: planning for failure on the application layer is the thing to do.
  2. Don’t put all your eggs in a single bucket: cloud platforms are based on different locations by nature, so you really should leverage this feature. True geographical redundancy can be hard to achieve, but try at least to have read replicas spread over the world, so that in case of downtime of your main region your service would just be degraded and not completely unreachable.
  3. Don’t think small. Some design patterns could seem overkills at first sight, but believe me, they are not. If you focus on designing your service so that it is ready for scaling up since the beginning, you won’t have to worry about later.
  4. Don’t implement complex software platforms: micro services are the way to go. Keep them simple and easy to maintain. It will be easier to scale each of them not only from a technical point of view: imagine how easy could be handing over not a part of a complex software, but a micro service to a new dedicated development team.
  5. Never forget that performance is the key: a killer SQL query could still be affordable if you have a low number of users, but is going to be an issue in the future. Make your platform as efficient as possible, also when it doesn’t seem strictly needed (yet).
  6. Don’t forget that everything could break, everytime. Keep your instances as simple as possible, so that they are easy to maintain. If one fails or starts misbehaving, just respawn it, don’t waste your time trying to fix. In an ideal world, they should be stateless.
  7. Vertical scaling is a no go. Choose the size of your instances based on the performance you want the single request to have, but always spread multiple requests horizontally. This will help the overall availability as well.
  8. Don’t be ‘legacy’: the world around you is moving very fast, and just looking at it makes no sense. New releases of software packages usually improve their performance, and new versions of the services your cloud provider is offering you usually improve everything, especially cost. Running a legacy instance type just because your platform is too hard to upgrade to a newer operating system, makes no sense and is going to kill your business in the long term.

Here we are. And now go and build!

A look into the scale of the Cloud

A look into the scale of the Cloud

I’ve spent hours doing various kinds of maths in order to figure out how big the big cloud providers actually are, and I tought it was worth sharing (part of) the results. Before showing you the numbers, I want to make sure who reads this post fully understands the method and the results, so please don’t jump to the numbers.

The most difficult part of the job was figuring out a way for measuring their size. Provided that my aim is not to calculate how big a single cloud provider actually is, but rather how they compare to each other, I decided to count the number of public IP addresses the company is using.

This number could seem easy to understand, but believe me it is not. It means nothing if you want to measure the size of a single platform, because we don’t know how those IP addresses are being used internally, and don’t know how many of them are being used by customers.

Moreover, we are in the cloud era, and thousands of instances could be hidden behind a single frontend with a single public IP: in this case, my calculation method would count them all as a single instance. This is the reason why I’m making a distinction between leaders and low cost providers.

It’s all about their typical use case: low cost providers generally don’t host big infrastructures or clusters, so their instances are more likely to be using public IP addresses. Leaders are hosting very large scale platforms, and they are more likely to host extremely high percentages of non public facing instances.

I’m counting for each cloud provider the number of IP addresses announced by its Autonomous System(s). In addition, leaders publish a list of IPs that they use (see Sources), but I’ve found this list to be used in different ways: Microsoft Azure for example is announcing all the ranges included in its list, but Amazon is not. I double checked and the ranges not being announced are really assigned to Amazon, so this simply means they aren’t being used (yet).

This is making the comparation yet more difficult to carry out, because in it we have players that simply announce to the internet any range they own, and others that announce only the ones actually in use or soon to be.

Finally, here are the numbers (remember the unit of measure is the single public IP address).


Amazon Microsoft Google
Announced 11,202,304 19,593,984 1,377,024
Declared 19,022,512 7,501,920 556,800

Low Cost

OVH DigitalOcean Hetzner Linode
Announced 1,709,312 930,560 906,752 325,632 311,296

And a graph.


Do you think I forgot someone? Please let me know!



Announced: IP ranges announced from the company’s one or more Autonomous Systems.

Declared: Amazon Web Services, Google Cloud*, Microsoft Azure.

* Ref: “Where can I find Compute Engine IP ranges?”

What an IaaS service is. And what it is not.

What an IaaS service is. And what it is not.

The term “Cloud Computing” has been openly used for almost ten years now, but there are still some misconceptions around the concept itself and around some more specific words like “IaaS” (Infrastructure as a Service).

Sometimes I have to face pointless discussions with people that have completely wrong ideas and expectations: this can be annoying from my point of view, but can be catastrophic for realities deciding to make “the big move” without having completely understood what the cloud is all about.


If you have come across this post as you’re still trying to figure out what “Cloud Computing” and “IaaS” mean, then let me save your life and probably your job with some clarifications.

The market offering isn’t helping us, as service providers are confused as well and they use to define “IaaS” completely unrelated products. The US NIST has released a document containing a list of 5 “Essential Characteristics” of cloud services, but they are not so specific and won’t help you make any choice.

When words are being used in such a confused way, you have to decide which of the many interpretations is the “authoritative” one: my authorities for this article are Amazon Web Services (and not because I work for them, but because ten years ago they have been the first at offering an IaaS platform) and OpenStack (that is, AWS concepts and terms reviewed by the biggest open source community in the cloud computing world).

So, what you should expect or not expect from an IaaS offering?

  • You should expect to be billed based on a Pay as you go model. Let’s be serious, if you have to pay an one time or monthly fee for your account and/or services you are using then this is not really cloud. Offering pay as you go services is a real technical challenge for the service provider, and if they aren’t giving you this option then you should have some doubts about them being up to date with the technology. Some providers will offer you discounts on long term commitments and this is fine, but always look for the PayG option, please.
  • You should expect to have full access to API and CLI tools and not just to a GUI. This is critical also if you are not planning to use them from the beginning. Cloud is all about automation, and if you stick with a service that only offers a GUI, then you will be forever bound to your mouse (and hands): if you come from an on premise physical server environment you could not see my point right now, but in the cloud you will start using automation soon, at least in its basic form. Because it’s easy and useful.
  • You should not expect your instances (virtual machines) to be always available. This is something I’ve already blogged about a few years ago (in italian, I’m sorry) but it’s still one of the biggest, most spread and more dangerous misconceptions. Cloud services are based on commodity hardware, and thus the instances on top of that should be considered in the same way, as a commodity. The single instance could be there or couldn’t be, and your customers don’t have to notice: you have to plan for high availability at application level, taking into account the various kinds of failure. Some additional services like Block Storage, Object Storage and Load Balancing as a Service will help you achieving the high levels of availability you need. If your service provider is offering you an extreme level of HA, then you’re probably paying for something you don’t need (if you’re using 5 web nodes, then what’s the matter if one of them goes down for a while?).
  • You should expect instant provisioning: seriously, provisioning has to happen in seconds. Be careful not to underestimate this: you could be happy with a 24 hours delivery time for your first bunch of servers, but believe me you won’t be when you will need to rapidly scale because of a traffic peak. Maybe I’m being too picky here but I expect the provisioning of my account to happen in real time as well: I’m not happy with providers asking me to send a physical signed contract or my IDs before using their service.
  • You should expect the service you choose not to have limits that could (and will) impact you. Okay, not all of us need the scale of AWS, but make sure your provider won’t go out of capacity when you will need it: planning for infrastructure is their job, and from your point of view you must always be able to use the resources you need, when you need them, with no previous commitment.
  • You should (probably) expect to have access to multiple autonomous regions: being it for active-active HA or just for backup and disaster recovery purposes, doesn’t make so much sense to choose a provider that is hosting its entire platform in a single datacenter. Yes, you could choose to use 2 different services providers hosting services in different locations, but this is not going to be easy to deal with.
  • You should (probably) expect not to be locked in by small-scale service providers: always look for open standards, expecially if the company you’re buying resources from is still at a scale where going out of business from one day to another is a (remote) possibility.
  • You should not expect to be able to easily scale vertically (increase instance size, or a single resource inside the instance): cloud computing is based on horizontal scalability (that means adding building blocks, not making the existing ones bigger), and this is why service provider don’t focus so much on hot resize of instances or on the ability to add RAM if you need RAM without modifying anything else. This is related to availability as well: if you can’t afford a planned downtime on a single instance in your infrastructure, then you’re doing something wrong.

That’s it, at least for now. I’m sure moving to the cloud is the right choice almost for every company in the world, but please make sure you fully understand it before making any choice. Really.


Time to clean things up.

Time to clean things up.

It was largely unexpected, but yesterday’s post had an enormous success. Okay, nothing compared to The Blonde Salad‘s posts, but I wasn’t expecting at all to get 500 visits in a couple of hours on a blog that I was considering as dead & forgotten.

This means it’s time to focus on improving your experience on this website. The weather in Ireland, where I currently am, is really helping me focus on my blog:


What I’ve done so far, in detail:

  • HTTPS: I finally completed the SSL integration. All static links have been modified to use HTTPS, and any HTTP URL is now redirecting to its SSL version.
  • Categories & Tags: I wasn’t using categories and relied on tags to categorize my posts. After a few years the tag cloud had become a real mess, so I spent a few hours in cleaning it up and reducing the number of tags per article. From now on, every post won’t have more than 5 tags and will belong to 2 categories: the real category, and a second one (English, Italian) based on its language.
  • Caching: WordPress wasn’t performing at its best, so I tuned W3 Total Cache and switched to Memcache as its backend. It’s much better now.
  • Permalinks: Sounds like my permalinks are not so permanent. I’ve modified some titles and URLs, so you should expect to incur in 404 errors for the next few days if you’re getting here via Google or old links.
  • MySQL: Yes, believe it or not, I was still using MySQL 5.5. Switched to MariaDB 10.1, and I’m in the process of tuning it: you should expect some brief downtimes in the next few hours, while I restart services.

That’s it, for now at least.

Stay tuned!

Giorgio is back!

Giorgio is back!

Yes, I’m back: this blog has been abandoned for like three years now, and I feel it’s time to bring it back to life. There is no particular reason behind this choice: I just need a virtual place where I can express my ideas and aggregate content I’ve always been disseminating over the internet for free (comments, forum posts, and so on).

New life means new theme (still in its basic version) and new language: some of my old posts are being read trough Google Translator, and as in the last few years my main language (mainly due to my job(s) and relationships) has been english, I have no reason at all to keep posting in italian. It’s just going to restrict my audience.

This time I won’t do what I did in all the previous “renovations”: I won’t destroy the old posts. The first one dates back to 2009 and I think they are a pretty important piece of history for them to disappear from the internet. I’m recovering the backups of the old versions of this blog in order to merge them with this one.

So, what has changed in those three years?

First, and maybe most important choice to date, I decided to put on hold (and then completely abandon) my studies at the University (Politecnico di Milano). This choice has been strongly dictated by the context (I was attending in Italy): although I perfectly understand the importance of learning the basis and developing a method for “doing things”, I felt what I was studying was too far behind reality. Spending years and thousands of euros to end up working as an underpaid intern in some big company was definitely not what I was expecting from my life.

The networking manual we were using (please mind it was 2013 and it was still being printed and was largely adopted) at a certain point stated that Ethernet was being superseded by FastEthernet, and that some big ISPs were deploying experimental long haul GigabitEthernet links. This was way too much (for non technical people reading this post: in 2013 we were already in the Terabit/s era, with multiple 100GigabitEthernet -100 times GbE- being used in long haul transits): reading this sentence, and then seeing that people that was able to get the best marks at the exam while thinking that GbE was the future (and not the past), helped me realize how detached from reality we were.

I decided to stop wasting time and joined CloudAcademy, a company that is trying to explain and show people how to take advantage of cloud services, as the Training Paths Supervisor. Feeling I had to head back to the battlefield, I decided in a few months to move to Enter, an italian ISP/CSP which at the time (late 2013) was working on the launch of a new multi-region OpenStack-based IaaS service, Enter Cloud Suite.

In Enter I have been employed first as a Cloud Architect and then as the Head of Cloud Architecture, with ECS as the main focus: I spent 2 years and a half designing and implementing hosting infrastructures for large scale news and e-commerce websites and designing, implementing and sometimes managing the OpenStack infrastructure behind Enter Cloud Suite. I was focused on the networking stack (both physical and overlay), and this gave me the opportunity to meet some very interesting realities like Cumulus Networks and Mellanox.

Then, in the first months of 2016, Amazon Web Services called: they offered me a position as a Technical Account Manager in London and I decided to accept it and move from Milan: everything happened so quickly I still have to realize what this means.

It’s very hard to explain what does it feel like being part of such a fast growing company, the one that has been the reference for your entire working life. “Work Hard. Have Fun. Make History.” is our slogan, and what it is all about: I’m sitting in the buildings where history is being written, day by day.

That’s it. This is the story of how I ended up writing this post, while laying on the bed in my apartment in Canary Wharf.

This is definitely a new beginning, and not just for this blog.


As you wait for the next post, please enjoy the view from my bedroom.


%d bloggers like this: