Tag Archives: Kubernetes

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 »

Kubernetes: PersistentVolume and PersistentVolumeClaim – an overview with examples

5 August 2020
 

 For the persistent data Kubernetes provides two main types of objects – the PersistentVolume and PersistentVolumeClaim. PersistentVolume – is a storage device and a filesystem volume on it, for example, it could be AWS EBS, which is attached to an AWS EC2, and from the cluster’s perspective of view, a PersistentVolume is a similar resource… Read More »

Kubernetes: manually restart a Cron Job

27 July 2020
 

 We have a Kubernetes Cron Job which failed on its last run. Let’s look for the root cause and then will see how to restart such a failed job. List current jobs: Check pods of the bttrm-apps-backend-reccuring-payment-cron Cron Job: The 1595844000-jzhrl pod was failed, check its logs: Actually, here is the issue cause: Failed to… Read More »

Kubernetes: ClusterIP vs NodePort vs LoadBalancer, Services, and Ingress – an overview with examples

24 June 2020
 

 For network communications, Kubernetes presents four Service types – ClusterIP (the default one), NodePort, LoadBalancer, and ExternalName, plus the Ingress resources. In this post, we will take a short overview of all of them, and will check how they are working. The documentation is available here – Publishing Services (ServiceTypes). I’m using AWS Elastic Kubernetes… Read More »

Kubernetes: 503 no endpoints available for service – causes and solutions

15 June 2020
 

 We have a Redis service running behind a Service with the ClusterIP type. This Redis must accessible by pods from the same namespace (a Gorush service). The problem is that those pod can’t connect to the Redis service using its gorush-server-redis-svc:6379 name and reporting “Can’t connect redis server: connection refused“: Although the service is present… Read More »

Helm: helm-secrets – sensitive data encryption with AWS KMS and use it with Jenkins

16 May 2020
 

 So, as a follow-up to the Helm: Kubernetes package manager – an overview, getting started post – let’s discuss about sensitive data in our Helm charts. What I want is to store a chart files in a repository, but even if such a repo will be a private Github repo – I still don’t want… Read More »

Helm: Kubernetes package manager – an overview, getting started

3 May 2020
 

 The official documentation calls Helm as a “The package manager for Kubernetes“, but in fact, Helm is something bigger than just a package manager – it’s more an application controlling tool for their installation, managing, upgrading, configuration, etc. In this post, we will take an overview of Helm in general, its Charts, templates, variables, and… Read More »