Category Archives: Monitoring

Hardware, services and network monitoring systems

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 »

Kubernetes: running metrics-server in AWS EKS for a Kubernetes Pod AutoScaler

15 February 2020

 Assuming, we already have an AWS EKS cluster with worker nodes. In this post – we will connect to a newly created cluster, will create a test deployment with an HPA – Kubernetes Horizontal Pod AutoScaler and will try to get information about resources usage using kubectl top. Kubernetes cluster Create a test cluster using… Read More »

Grafana: Loki – the LogQL’s Prometheus-like counters, aggregation functions and dnsmasq’s requests graphs

17 November 2019

 The last time I configured Loki for logs collecting and monitoring was in February 2019 – almost a year ago, see the Grafana Labs: Loki – logs collecting and monitoring system post, when Loki was in its Beta state. Now we faced with outgoing traffic issues in our Production environments and can’t find who guilty for… Read More »

dnsmasq: AWS – “Temporary failure in name resolution”, logs, debug and dnsmasq cache size

28 October 2019

 We are using AWS VPC DNS and sometimes facing with errors like “php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution“. The only advice from AWS tech. support was to configure a local dnsmasq service to act as a local DNS cache, but I did this already year ago and this issue happens once in 1-2-3… Read More »

Debian: logrotate won’t rotate logs with an “unknown group ‘syslog'” error

9 October 2019

 We have an AWS EC2 with Debian and logrotate. One day its root partition was exhausted and when I started investigating it – found, that we have a bunch of files like /var/log/syslog.N.gz. At the same time by default logrotate creates a config file to rotate syslog log files: Thus, we must have only files… Read More »

OpsGenie: Uptrends integration

24 September 2019

 Uptrends – just a simple pinging monitoring service already used for the RTFM blog (see the Prometheus: RTFM blog monitoring set up with Ansible – Grafana, Loki, and promtail post for more details). Now I’d like to add it as an additional alerting service for the project’s API-endpoints and configure its alerts to be sent… Read More »

Prometheus: Alertmanager’s alerts receivers and routing based on severity level and tags

26 March 2019

 We have three working environments – Dev, Stage, Production. Also, there are a bunch of alerts with different severities – info, warning и critical. For example: … – name: SSLexpiry.rules rules: – alert: SSLCertExpiring30days expr: probe_ssl_earliest_cert_expiry{job=”blackbox”} – time() < 86400 * 30 for: 10m labels: severity: info annotations: summary: “SSL certificate warning” description: “SSL certificate… Read More »