Pods are not recreated after kubernetes node failure

  We had a short outage recently which was caused by the pods were not recreated on other nodes when the previous node become unresponsive. It is Kubernetes 1.6, and according to the documentation, it is expected in some cases. "If the Status of the Ready condition is “Unknown” or “False” for longer than the … Continue reading Pods are not recreated after kubernetes node failure


Horizontal Pod Autoscaling

I did a quick test of the HPA (Horizontal Pod Autoscaling) on OpenShift, here are some key findings: Heapster metric is not near realtime, it is about 2 minutes delay in my test. HPA only has one threshold to decide when to scale up or scale down. I think it makes sense, as pods normally … Continue reading Horizontal Pod Autoscaling

Autoscaler on OpenShift Dedicated

At the time of writing, OpenShift dedicated (v3.5.5.31) only supports autoscaling based on the CPU metrics. So the first step is to ensure the CPU request is in place. It can be setup in the section of container spec. e.g spec: containers: image: 'poc/web' name: my-web ports: - containerPort: 3000 resources: requests: cpu: 200m limits: … Continue reading Autoscaler on OpenShift Dedicated

Build smart into your docker images

We have been running mysql 5.7 on OpenShift with RedHat provisioned images.  To make it work is easy, but to make it work correctly is a bit harder. One example is that how to setup the innodb_buffer_pool_size (one of the most important parameters of mysql)? When you build the image you don't know how much memory the … Continue reading Build smart into your docker images

Resources QoS in Kubernetes

I extracted a few points to grasp the rough idea of how Kubernetes manages resources QoS: Pods that need to stay up reliably can request guaranteed resources, while pods with less stringent requirements can use resources with weaker or no guarantee. If a pod is successfully scheduled, the container is guaranteed the amount of resources … Continue reading Resources QoS in Kubernetes