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Quorten Blog 1

First blog for all Quorten's blog-like writings

Creating containers in Kubernetes

quorten

2018-08-09

Categories: kubernetes  
Tags: kubernetes  

First of all, how do you create containers on Kubernetes?

  1. kubectl command

  2. Helm charts

With the kubectl command, typically you want to create a manifest file that you then use to create the resource using just kubectl apply -f file.yml. Note that “Helm charts” are typically just manifest files with templating, so you can always take a Helm chart deployment and turn it into a manifest file by filling in the templating by hand.

For example, for Redis, either redis-cluster or redis-sentinel (HA).

20180809/https://github.com/helm/charts/tree/master/stable/redis
20180809/https://github.com/helm/charts/tree/master/stable/redis-ha

Particularly, for creating development or short-term interactive containers in Kubernetes, the kubectl run command is particularly instrumental:

kubectl run --rm -it my-ubuntu --image=ubuntu \
  --limits='cpu=200m,memory=512Mi'

For installing Helm, keep this in mind. If you are on a shared cluster with namespaces and role-based access control (RBAC), then you will need to make sure there is a serivce account available for Helm before you install Helm Tiller.

20180809/https://helm.sh/
20180809/https://docs.helm.sh/using_helm/#quickstart
20180809/https://docs.helm.sh/using_helm/#role-based-access-control

Resource limit CPU = 200m? In Kubernetes, that means limit CPU usage to 200 milli-cores. Yep, it’s not instructions or time slices, its in units of “processor cores.”

20180809/DuckDuckGo kubernetes resource limits
20180809/http://callmeradical.com/post/k8s-resource-limits-requests-qos/