Category Archives: HOWTO’s

Networking: when there is no power – ZTE 4G modem + external antenna
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19 November 2022

What to do when there is no electricity, mobile communication towers are turned off, and you want to watch the outcasts with Ukrainian cats? That’s right – buy yourself a 3/4G modem with an antenna! In addition, the antenna itself does not need power, and the modem can be inserted into an ordinary power bank,… Read More: Networking: when there is no power – ZTE 4G modem… »

Linux: saving laptop’s battery energy
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19 November 2022

This time it became interesting to me – is it possible to somehow save the charge of the laptop battery? Not to say that it discharges quickly, it is enough for 5-6 hours of work, but it will not be too much, especially with the current power outages in Ukraine. Found several utilities, and will… Read More: Linux: saving laptop’s battery energy0 (0) »

Pritunl: running VPN in Kubernetes
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5 October 2022

Pritunl is a VPN server with a bunch of advanced security and access control features. In fact, it is just a wrapper over OpenVPN, adding such Access Control Lists to it in the form of Organizations, users, and routes. The task is to deploy a Pritunl test instance in Kubernetesб so we can take a closer… Read More: Pritunl: running VPN in Kubernetes0 (0) »

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Kubernetes: Minikube, and a LoadBalancer in the Pending status
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5 October 2022

After running Pritunl in Minikube, it is not possible to connect to the VPN: … 2022-10-03 13:50:32 TCP/UDP: Preserving recently used remote address: [AF_INET]194.168.3.100:1194 2022-10-03 13:50:32 UDP link local: (not bound) 2022-10-03 13:50:32 UDP link remote: [AF_INET]194.168.3.100:1194 … Check its Kubernetes Service: [simterm] $ kubectl -n pritunl-local get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE… Read More: Kubernetes: Minikube, and a LoadBalancer in the Pending status0 (0) »

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PostgreSQL: PostgreSQL Operator for Kubernetes, and its Prometheus monitoring
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23 September 2022

So, we’ve launched Druid, see Apache Druid: Overview, Running in Kubernetes, and Monitoring with Prometheus . So far, a local Apache Derby database is used as the default storage for metadata . Next, we will switch Druid to PostgreSQL, and later we will remove ZooKeeper from the cluster setup. To begin with, let’s start a PostgreSQL cluster in Kubernetes, add… Read More: PostgreSQL: PostgreSQL Operator for Kubernetes, and its Prometheus monitoring0 (0) »

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Apache Druid: overview, running in Kubernetes and monitoring with Prometheus
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18 September 2022

Apache Druid is a columnar database, focused on working with large amounts of data, combining the features and benefits of Time-Series Database, Data Warehouse, and a search engine. The general task is to set up monitoring of the Druid cluster in Kubernetes, so at first, we will see what it is in general and how… Read More: Apache Druid: overview, running in Kubernetes and monitoring with Prometheus0… »

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AWS: VPC Flow Logs – an overview and example with CloudWatch Logs Insights
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19 July 2022

AWS VPC Flow Logs allow you to log traffic information between network interfaces in a VPC. Further, these logs can be stored in AWS S3 or sent to AWS CloudWatch Logs, while enabling traffic logging does not affect the performance of the network interface in any way. Let’s briefly review the basic concepts, and available… Read More: AWS: VPC Flow Logs – an overview and example with… »

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NGINX: IP Geolocation by Cloudflare and “nested” if conditions
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2 April 2022

Among other features provided by Cloudflare, it can add a special header with a country value, from where a visitor came. As a Ukrainian, I’d like to ban all visitors from russia, but: redirect all visitors from russian IPs to another web domain – russki-voenny-korabl-idi-nahuy.com during this, I’d like to filter requests and leave requests… Read More: NGINX: IP Geolocation by Cloudflare and “nested” if conditions0 (0) »

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Cloudflare: speed up WordPress with Automatic Platform Optimization plugin
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30 March 2022

The rtfm.co.ua blog is quite slow for users. For example, you can test your website using the https://gtmetrix.com: 4.3 seconds till full load! That’s awful. At the bottom of the results, you can check top of issues on a site: At first, the page size is 1.16 MB, which is big enough. The second thing… Read More: Cloudflare: speed up WordPress with Automatic Platform Optimization plugin0 (0) »

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Elastic Stack: an overview and ELK installation on Ubuntu 20.04
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22 February 2022

The last time I’ve worked with the ELK stack about 7 years ago, see the ELK: установка Elasticsearch+Logstash+Kibana на CentOS. Currently, we are using Logz.io, but its costs going higher and higher, so we started looking at the self-hosted ELK solution to be running on our AWS Elastic Kubernetes Service clusters. So, the task, for… Read More: Elastic Stack: an overview and ELK installation on Ubuntu 20.040… »

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