Category Archives: Monitoring

Hardware, services and network monitoring systems collection logs from Kubernetes – fluentd vs filebeat

1 February 2021

 We are using to collect our Kubernetes cluster logs (also, there is a local Loki instance). Logs are collected and processed by a Fluentd pod on every WorkerNode which are deployed from a DaemonSet in its default configuration, see the documentation here – logzio-k8s. The problem we faced is that those pods are consuming… Read More »

Prometheus: Alertmanager Web UI alerts Silence

26 January 2021

 Active alerts sending frequency via Alertmanager is configured via the repeat_interval in the /etc/alertmanager/config.yml file. We have this interval set to 15 minutes, and as result, we have notifications about alerts in our Slack each fifteen minutes. Still, some alerts are such a “known issues”, when we already started the investigation or fixing it, but… Read More »

Linux: LEMP set up – NGINX, PHP, MySQL, SSL, monitoring, logs, and a WordPress blog migration

6 November 2020

 Finally got time to migrate the RTFM.CO.UA blog to a new server with Debian 10. This time manually, without any automation will set up a LEMP stack Wrote a similar at 2016 – Debian: установка LEMP — NGINX + PHP-FPM + MariaDB (Rus), but in time the post is more complete of the process and… Read More »

Kubernetes: load-testing and high-load tuning – problems and solutions

4 September 2020

 Actually, this post was planned as a short note about using NodeAffinity for Kubernetes Pod: But then, as often happens, after starting writing about one thing, I faced another, and then another one, and as a result – I made this long-read post about Kubernetes load-testing. So, I’ve started about NodeAffinity, but then wondered how… Read More »

Kubernetes: a cluster’s monitoring with the Prometheus Operator

13 August 2020

 Continuing with the Kubernetes: monitoring with Prometheus – exporters, a Service Discovery, and its roles, where we configured Prometheus manually to see how it’s working – now, let’s try to use Prometheus Operator installed via Helm chart. So, the task is spin up a Prometheus server and all necessary exporter in an AWS Elastic Kubernetes… Read More »

Kubernetes: HorizontalPodAutoscaler – an overview with examples

12 August 2020

 Kubernetes HorizontalPodAutoscaler automatically scales Kubernetes Pods under ReplicationController, Deployment, or ReplicaSet controllers basing on its CPU, memory, or other metrics. It was shortly discussed in the Kubernetes: running metrics-server in AWS EKS for a Kubernetes Pod AutoScaler post, now let’s go deeper to check all options available for scaling. For HPA you can use three… Read More »

Prometheus: yet-another-cloudwatch-exporter – collecting AWS CloudWatch metrics

23 July 2020

 Currently, to collect metrics from the AWS CloudWatch we are using AWS’s own cloudwatch-exporter, see the Prometheus: CloudWatch exporter — сбор метрик из AWS и графики в Grafana post (in Rus), but it has a few gaps: it’s written in Java, so uses CPU/memory of the monitoring host doesn’t scrapes AWS tags from resources uses… Read More »

Kubernetes: monitoring with Prometheus – exporters, a Service Discovery, and its roles

26 April 2020

 The next task with our Kubernetes cluster is to set up its monitoring with Prometheus. This task is complicated by the fact, that there is the whole bunch of resources needs to be monitored: from the infrastructure side – ЕС2 WokerNodes instances, their CPU, memory, network, disks, etc key services of Kubernetes itself – its… Read More »

Redis: “psync scheduled to be closed ASAP for overcoming of output buffer limits” and the client-output-buffer-limit

26 February 2020

 We have a Redis-cluster with Master-slave replication and Sentinel, see the Redis: replication, part 2 – Master-Slave replication, and Redis Sentinel, Redis: fork – Cannot allocate memory, Linux, virtual memory and vm.overcommit_memory, and Redis: main configuration parameters and performance tuning overview posts. The system worked great until we started using it much more actively. Redis… Read More »