Myths about clouds

Recently, I have quite a lot of clients migrating to the clouds, mostly to the Amazon, and all of them are subject to roughly the same myths about clouds. And I have to constantly dispel these misconceptions and misunderstandings. In this article, I’ll talk about IAAS (infrastructure as a service) such cloud companies as Amazon, Rackspace, Linode, digitalocean, for PAAS everything looks a bit different.

Clouds are reliable, there will be a good uptime and no need backups.

Clouds remove some of the problems with iron, due to virtualization and live migration of virtual machines from problematic machines. But clouds are also prone to network and datacenter or cluster level problems. Here you need a couple of examples, quite often the data centers of a cloud provider fall completely and at the same time all virtual clouds of a cloud fall. Sometimes there are network problems and the whole ds is not available or its traffic is sent to a black hole. There are problems with the disk subsystem and sometimes they lead to a complete loss of data (recently such letters of happiness came to some Amazon customers, and those who did not have backup lost all their data).
Western clouds are less susceptible to the problems described above, and those who use Russian clouds are likely to know all the pain described above (remember the closed skalaxi, the fall of the clod, the fakapy select).
The reliability of the cloud lies in the ability to create a distributed system with large cloud providers, choosing different DCs and continents, using convenient methods of load distribution, creating backups and so on. That is, if you bought one cloud plan, then you still quite tasted all the charms of the cloud, and all hosters now probably became cloudy and spread over a bunch of servers on different continents.

Clouds are about vertical scaling.

The world's top providers still do not support automatic memory and processor updates on the fly, since these mechanisms were not very simple in older versions of virtualization, and in current ones everything is also not smooth, and there are also certain problems with regard to memory in linux.
Here it should be noted that the Russian clouds are almost completely able to vertical scaling. But in general, the clouds are built so that they are oriented to horizontal scaling, and not vertical.

I launched my application in the cloud and it will scale itself.

Usually, after dispelling this myth, customers feel a little sad, but it’s not so easy to take and scale any wordpress and transfer it to the cloud. Any scaling requires certain actions to modify the application infrastructure and often the application code. The simplest thing is to take the code to the file server, take out the database and scale the application server, and somehow try to scale the database.
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Clouds faster than not clouds or will any particular cloud withstand my application?

Here I try to explain to the client that the megahertz of the processor and the megabytes of memory are all the same, and it all depends on how much he is willing to buy them and the price of the cloud. And that there is no difference in the performance of 4 nuclear Dedik at 3 Hz and with 8 GB of memory and a cloud with the same parameter, be it Amazon or digitalocean.com, but the first serious cloud provider with many buns and dozens of data centers around the world.

Clouds are cheap.

There is a myth from Russian users, and here goes the story of how I got into some selector and it cost me 50 rubles. In fact, the clouds are very expensive, using scaling (vertical or horizontal) and having a sinusoidal load, you can save on unused resources twice, only twice, while the clouds are sometimes ten times more expensive than the same cheap dedikov.
To save a Dedik with 32 gigabytes of RAM, 8 cores cost 70 euros in the same hetzner, a similar config in Amazon Linux on cc1.4xlarge will result in almost $ 1000 without traffic and disks.

Clouds it's not clear

Yes, there is a certain entry threshold, mostly related to differences in terminology and work options.
For example, all clouds are essentially ordinary vps in a cluster, and I simply decode the terms
ec2 instance - vps
ebs - hdd
elastics ip - dedicated static ip for vps
and so on

Clouds are safely moved and all is well

In general, the clouds provide a certain number of mechanisms for protection, but in general, all protection from everything falls on your shoulders and you are not becoming more coordinated in the cloud. Well, sometimes in prose clouds go through pci compliance for accepting credit cards.

From not a myth, I will note a slow disk subsystem in almost all clouds, you understand this well when you raise an instance on ssd clouds of the type of digital ocean. In Russia, the clouds are worse than in the west due to the lower infrastructure and software reliability, that is, Russian clouds are younger and so far still cones are stuffed.

If you are going to migrate to the clouds and you have questions, feel free to ask them in the comments
or email elektrichestvonsk@gmail.com

Good luck in the clouds.