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Managing AWS Auto Scaling Group Instance Refresh: The Harmony of Terraform and Ansible

Level of difficultyMedium
Reading time6 min
Views705

In the DevOps realm, where automation is crucial, the management of resources and updating processes in the cloud is vitally important. Many modern projects, particularly in AWS cloud environments, leverage Auto Scaling Groups (ASG). This mechanism aims to achieve three key objectives: balancing loads, increasing service reliability, and optimizing operational costs for efficiency and effectiveness.

Imagine working at a company where you deploy applications on Amazon's resources. To streamline this process and manage configurations more effectively, you use pre-built AMI images. These are crafted with tools like HashiCorp Packer, ensuring your applications launch swiftly and reliably. For the actual infrastructure deployment, you turn to Terraform. It's widely recognized as the standard in many major companies for managing cloud resources and using the IaC (Infrastructure as Code) approach.

As an IT engineer, you sometimes need to update instance versions to a newer AMI image, either for the latest security patches or to introduce new functionalities. The challenge lies in updating an active ASG without causing downtime. It's crucial to ensure the new AMI performs as reliably as the existing one, balancing the need for updates with system stability and uptime.

ASG's instance refresh is a crucial feature that allows for updating instances within a group while minimizing downtime, thereby maintaining high availability. However, ensuring the success of such updates, especially in large, complex systems, can be a challenge. Terraform resources, such as aws_autoscaling_group, can initiate this process but don't provide progress tracking. This limitation becomes apparent when other infrastructure components, such as certificate renewals or DNS updates, depend on the state and version of the instances. Monitoring the update process is essential to maintain an accurate infrastructure state after Terraform's execution.

To overcome this challenge, Ansible can be utilized...

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Total votes 4: ↑4 and ↓0+4
Comments0

Modern Micro-Service Architecture: Key Challenges for System Analysts

Reading time9 min
Views1.7K

We're continuing to explore micro service architecture. In today's blog Alexander Solyar, Lead system architect at Innotech, describes the main challenges analysts are facing while working with micro services. He also shares a number of effective solutions and recommendations.

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Total votes 3: ↑3 and ↓0+3
Comments0

Modern Microservice Architecture: Design Principles

Reading time7 min
Views3.6K

First mentions of micro service architecture application go back to the previous decade. Today this approach became the industry standard. Alexander Solyar, Lead software architect at Innotech, dives into details, shares professional insights and practical rules for working with micro services .

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Total votes 3: ↑3 and ↓0+3
Comments1

HTTP headers checker

Reading time2 min
Views2.8K
For any site, it is important to properly configure the HTTP headers. A lot of articles have been written on the subject of headings. Here we have summarized the lessons learned, the RFC documentation. Some of the headings are mandatory, some are obsolete, some can be confusing and contradictory. We did a parsing to automatically check the HTTP headers of the web server.

Correct HTTP headers increase security and trust in the site, including from search engines, can affect the site’s position in Yandex and Google, save server resources, reduce server load, thereby increasing the server response speed, which again affects the ranking of the site in the search, save money on payment powerful hosting, which may not be required for the site when configured correctly.
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Rating0
Comments2

Bcache against Flashcache for Ceph Object Storage

Reading time11 min
Views2.6K

Fast SSDs are getting cheaper every year, but they are still smaller and more expensive than traditional HDD drives. But HDDs have much higher latency and are easily saturated. However, we want to achieve low latency for the storage system, and a high capacity too. There’s a well-known practice of optimizing performance for big and slow devices — caching. As most of the data on a disk is not accessed most of the time but some percentage of it is accessed frequently, we can achieve a higher quality of service by using a small cache.

Server hardware and operating systems have a lot of caches working on different levels. Linux has a page cache for block devices, a dirent cache and an inode cache on the filesystem layer. Disks have their own cache inside. CPUs have caches. So, why not add one more persistent cache layer for a slow disk?
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Total votes 16: ↑16 and ↓0+16
Comments0

Ansible: CoreOS to CentOS, 18 months long journey

Reading time4 min
Views1.5K


There was a custom configuration management solution.


I would like to share the story about a project. The project used to use a custom configuration management solution. Migration lasted 18 months. You can ask me 'Why?'. There are some answers below about changing processes, agreements and workflows.

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Total votes 3: ↑3 and ↓0+3
Comments2

Safe-enough linux server, a quick security tuning

Reading time10 min
Views2.6K
The case: You fire up a professionally prepared Linux image at a cloud platform provider (Amazon, DO, Google, Azure, etc.) and it will run a kind of production level service moderately exposed to hacking attacks (non-targeted, non-advanced threats).

What would be the standard quick security related tuning to configure before you install the meat?


release: 2005, Ubuntu + CentOS (supposed to work with Amazon Linux, Fedora, Debian, RHEL as well)


image

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Total votes 3: ↑2 and ↓1+5
Comments0

Connect to Windows via SSH like in Linux

Reading time3 min
Views12K
The most depressing thing for me is to connect to Windows hosts. I'm not an opponent or a fan of Microsoft and their's products. Every product has its own purpose. But it is really painful for me to connect to Windows servers, because of 2 points: it is hard to configure (Hi WinRM with HTTPS), and it is really unstable (Hello RDP to VMs across the ocean).

Fortunately, I found the project Win32-OpenSSH. I realized that I want to share my experience with it. I believe it will help somebody and save a lot of nerves.


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Total votes 6: ↑6 and ↓0+6
Comments0

From High Ceph Latency to Kernel Patch with eBPF/BCC

Reading time9 min
Views4.9K


There are a lot of tools for debugging kernel and userspace programs in Linux. Most of them have performance impact and cannot easily be run in production environments. A few years ago, eBPF was developed, which provides the ability to trace the kernel and userspace with low overhead, without needing to recompile programs or load kernel modules.

There are now plenty of tools that use eBPF and in this article, we’ll explain how to write your own profiling tool using the PythonBCC library. This article is based on a real issue from the production environment. We’ll walk you through solving the problem and show how existing bcc tools could be used in some cases.
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Total votes 13: ↑11 and ↓2+9
Comments0

How Many Developers Need to Create Service Like Airbnb

Reading time4 min
Views3K
Back in 2007, Brian Chesky and Joe Gebbia shared a room in San Francisco and were unable to pay rent on time. As a way out, they decided to turn their living space into a simple bed-and-breakfast hotel to get some money from travelers. If you love traveling i can advice you Travel news site. A year later, the venturers launched a website which evolved into the most famous peer-to-peer renting technology service called Airbnb.

 Now, the company has 3,100 employees and generates insane revenues for its founders. The statistics say that Airbnb has 150 million registered users, 3 million hosts, and 4 million listed offers. The service covers 80,000 cities in 190 countries, and, interestingly, 50% of traffic comes from mobile applications.

  These figures are so impressive that you may also want to create your own Airbnb clone and become successful. But slow down. This story is already written; do you really need to create a marketplace similar to Airbnb?
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Total votes 14: ↑13 and ↓1+12
Comments0

How Protonmail is getting censored by FSB in Russia

Reading time10 min
Views8.5K

A completely routine tech support ticket has uncovered unexpected bans of IP addresses of Protonmail — a very useful service for people valuing their Internet freedoms — in several regions of Russia. I seriously didn’t want to sensationalize the headline, but the story is so strange and inexplicable I couldn’t resist.


TL;DR


Disclaimer: the situation is still developing. There might not be anything malicious, but most likely there is. I will update the post once new information comes through.


MTS and Rostelecom — two of the biggest Russian ISPs — started to block traffic to SMTP servers of the encrypted email service Protonmail according to an FSB request, with no regard for the official government registry of restricted websites. It seems like it’s been happening for a while, but no one paid special attention to it. Until now.


All involved parties have received relevant requests for information which they’re obligated to reply.


UPD: MTS has provided a scan of the FSB letter, which is the basis for restricting the access. Justification: the ongoing Universiade in Krasnoyarsk and “phone terrorism”. It’s supposed to prevent ProtonMail emails from going to emergency addresses of security services and schools.


UPD: Protonmail was surprised by “these strange Russians” and their methods for battling fraud abuse, as well as suggested a more effective way to do it — via abuse mailbox.


UPD: FSB’s justification doesn’t appear to be true: the bans broke ProtonMail’s incoming mail, rather than outgoing.


UPD: Protonmail shrugged and changed the IP addresses of their MXs taking them out of the blocking after that particular FSB letter. What will happen next is open ended question.


UPD: Apparently, such letter was not the only one and there is still a set of IP addresses of VOIP-services which are blocked without appropriate records in the official registry of restricted websites.

Total votes 66: ↑64 and ↓2+62
Comments4

Writing yet another Kubernetes templating tool

Reading time8 min
Views12K


If you are working with Kubernetes environment then you probably make use of several existing templating tools, some of them being a part of package managers such as Helm or Ksonnet, or just templating languages (Jinja2, Go template etc.). All of them have their own drawbacks as well as advantages and we are going to go through them and write our own tool that will try to combine the best features.

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Total votes 22: ↑21 and ↓1+20
Comments1

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