Category Archives: Virtualization

In computing, virtualization refers to the act of creating a virtual version of something, including virtual computer hardware platforms, storage devices, and computer network resources.

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 – the cause and solution

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 proble 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“: Althought the service is present… Read More »

AWS: CloudFormation – using Conditions, Fn::Equals, and Fn::If – an example

17 May 2020
 

 I have a CloudFormation stack with VPC Peerings, in that case, it’s a peering between VPC of a new Elastic Kubernetes Service cluster and VPC of the Prometheus monitoring stack. The EKS cluster’s stack and its whole automation creation were described in the AWS Elastic Kubernetes Service: a cluster creation automation, part 1 – CloudFormation… Read More »

Docker: configure tzdata and timezone during build

17 May 2020
 

 During a Docker image build – it stops asking to configure the tzdata. Dockerfile at this moment is the next: FROM ubuntu:18.04 RUN apt update && apt install -y python-pip python-dev ssh python-boto3 RUN pip install ansible==2.4.3.0 Let’s reproduce – run the build: And here it hangs waiting for us enter data, and even after… 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 »

AWS: CloudFormation – using lists in Parameters

8 May 2020
 

 In addition to the AWS Elastic Kubernetes Service: a cluster creation automation, part 1 – CloudFormation and AWS Elastic Kubernetes Service: a cluster creation automation, part 2 – Ansible, eksctl posts – now I’d like to pass a Parameter as a List with multiply values to a CloudForamtion stack. The idea is to get all… 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 »

AWS Elastic Kubernetes Service: a cluster creation automation, part 2 – Ansible, eksctl

1 May 2020
 

 The first part – AWS Elastic Kubernetes Service: a cluster creation automation, part 1 – CloudFormation. To remind the whole idea is to create an automation process to create an EKS cluster: Ansible uses the cloudformation module to create an infrastructure by using an Outputs of the CloudFormation stack created – Ansible from a template will… 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 »

AWS: eksctl – “Put http://169.254.169.254/latest/api/token: net/http: request canceled”

26 April 2020
 

 We have a Docker image with the eksctl tool included. We also have an ЕС2 with Linux with the eksctl. There is an AWS IAM Instance Profile attached to this EC2 with the AdminAccess policy assigned. On this ЕС2 we have Jenkins running in a Docker container, and it spawns its jobs inside in additional… Read More »