Tag Archives: Kubernetes

Kubernetes: metrics-server – “401 Unauthorized” amd “kubelet stopped posting node status”

23 April 2021
 

 On our AWS Elastic Kubernetes Service Dev cluster, we got a couple of namespaees hanging i nthe Termination state. “401 Unauthorized”, response: “Unauthorized” Remembering a similar issue where the root cause was the metrics-server (see the Kubernetes: namespace hangs in Terminating and metrics-server non-obviousness post for details), the first thing I did was to check… Read More »

Istio: external AWS Application LoadBalancer and Istio Ingress Gateway

22 April 2021
 

 In the previous post, Istio: an overview and running Service Mesh in Kubernetes, we started Istion io AWS Elastic Kubernetes Service and got an overview of its main components. The next task is to add an AWS Application Load Balancer (ALB) before Istio Ingress Gateway because Istio Gateway Service with its default type LoadBalancer creates… Read More »

Kubernetes: NodeLocal DNS and the “lookup istiod.istio-system.svc on lookup: no such host” error

19 April 2021
 

 In our Deployments, we are using the NodeLocal DNS as a local DNS cache to reduce requests number to the AWS VPC DNS, see the Kubernetes: load-testing and high-load tuning – problems and solutions for details. Currently, a manifest looks like the next: … dnsPolicy: “None” dnsConfig: nameservers: – 169.254.20.10 … The problem is, that… Read More »

Istio: an overview and running Service Mesh in Kubernetes

11 April 2021
 

 Istio is a Service Mesh solution that allows performing Service Discovery, Load Balancing, traffic control, canary rollouts and blue-green deployments, traffic monitoring between microservices. We will use Istio in our AWS Elastic Kubernetes Service for traffic monitoring, as an API Gateway service, for traffic policies, and for various deployment strategies. In this post, will speak… Read More »

Kubernetes: ExternalDNS – records retrieval failed: failed to list hosted zones: Throttling: status code: 400

9 April 2021
 

 We have an ExternalDNS service running, see the Kubernetes: update AWS Route53 DNS from an Ingress post, which started sending a lot of messages like: msg=”failed to list resource records sets for zone /hostedzone/Z2VM3W5SRY4I9J: Throttling: \n\tstatus code: 400 And even AWS Console in the Route53 says “Throttling error that was caused because API rate was… Read More »

Kubernetes: Cluster Autoscaler – failed to renew lease

7 April 2021
 

 We have a Kubernetes Cluster Autoscaler for AWS EC2 WorkerNode groups scaling. On our Dev cluster sometimes it stop working with the following message in its logs: [simterm] … E0331 08:57:52.264549 1 leaderelection.go:320] error retrieving resource lock kube-system/cluster-autoscaler: Get https://172.20.0.1:443/apis/coordination.k8s.io/v1/namespaces/kube-system/leases/cluster-autoscaler: context deadline exceeded I0331 08:58:14.468096 1 leaderelection.go:277] failed to renew lease kube-system/cluster-autoscaler: timed out waiting… Read More »

Kubernetes: namespace hangs in Terminating and metrics-server non-obviousness

1 April 2021
 

 Faced with a very interesting thing during removal of a Kubernetes Namespace. After a kubectl delete namespace NAMESPACE is executed, the namespace hangs in the Terminating state, and any attempt to forcibly remove it didn’t help. First, let’s see how such a force-removal can be done, and then will check the real cause and a… Read More »

Kubernetes: what is Endpoints

13 March 2021
 

 Usually, we don’t see Endpoints objects when using Kubernetes Services, as they are working under the hood, similarly to ReplicaSets which are “hidden” behind Kubernetes Deployments. Kubernetes Service So, Service is a Kubernetes abstraction that uses labels to chose pods to route traffic to, see the Kubernetes: ClusterIP vs NodePort vs LoadBalancer, Services, and Ingress… Read More »

AWS: InvalidSignatureException: Signature not yet current and Kubernetes AWS ALB Ingress controller

4 March 2021
 

 One day our developers said that they can not create new AWS LoadBalancers via Ingress on our Kubernetes Dev cluster (AWS EKS). Balancers are created using AWS ALB Controller, see AWS Elastic Kubernetes Service: running ALB Ingress controller. Errors in the controller’s logs were: E0304 07:12:38.595113       1 controller.go:217] kubebuilder/controller “msg”=”Reconciler error” “error”=”no object matching key… Read More »

Jenkins: running workers in Kubernetes and Docker images build

27 February 2021
 

 We have a Jenkins instance that is running jobs in Docker containers on its host. Eventually, we’ve faced with an issue when the current AWS Ec2 instance t2.2xlarge (8 CPU, 32 RAM) during peak workload periods was too overloaded – not enough CPU time, not enough memory. So, the first solution could be to proceed… Read More »