k8s-commands

This is a collection of notes from the internet on how to do things kubernetes

Most common ways people install Kubernetes

• Minikube: For local developement
• kops and Kubeadm: For clouds and bare metal

General Management Tools

• Dashboard: Visualization
• Kubefed: For Larger cluster federation
• Kompose: For Exporting from docker with compose
• Helm: For Large application management

Creating a cluster

When creating a cluster from an image, you can also use the run command.

• kubectl run give-name-of-cluster --image repo-name/image-name:latest

Common way (from file): To use a yaml file within your local computer, use the command

• kubectl create -f file-2-deploy.yaml

Multiple files:

• kubectl create -f file-1-deploy.yaml file-2-deploy.yaml

Whole directory: Must have .yaml files

• kubectl create ./cluters

URL:

• kubectl apply -f https://github.com/Cosmos-it/k8s-commands/blob/master/sample.yaml

Using namespaces

Working with many applications

Deploy sample infrastructure:

• kubectl apply -f sample.yaml

apiVersion: v1
kind: Pod
metadata:
  name: sample
spec:
  containers:
  - name: sample
    image: ubuntu

Namespaces

• kubectl get pods returns no results.
• kubectl get pods --all-namespaces returns all our results.
• kubectl get namespaces Returns just the namespaces

More details on searching, sorting and filtering applications on kubernetes

• kubectl get pods --sort-by=.metadata.name sorts pods by name
• kubectl get pods -o wide --all-namespaces returns more details
• kubectl get pods/cart-dev -n cart -o json returns the pod json
• kubectl get pods -n cart -o=jsonpath="{..image}" -l app=cart-dev searches cart-dev, and returns the image based on the jsonpath
• kubectl get pods --all-namespaces -o jsonpath="{.items[*]- .spec.containers[*].image}" all container images running

Understand how to delete pods, and resources in k8s

• kubectl delete pods --all deletes all pods in the default namespace
• kubectl delete pods -n cart --all deletes all pods in the cart namespace
• kubectl delete pods -l env=staging -n social Deletes the pods in the social namespace that match the staging environment

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Take a break here

Kops with AWS

To use kops to run your own kubernetes cluster, you will need to the following.

Install and set

• kops
• kubectl
• AWS credentials
• AWS CLI tools

AWS requirements

• Set up IAM account: Give ut full access to s3, EC2, Route53, and IAM
• Create DNS record for the kubernetes services

Setup a cluster

• export NAME=mycluster.k8s.local
• export KOPS_STATE_STORE=s3://prefix-example-com-state-store

Build cluster

• kops create cluster \ --zones use-west-2b \ ${NAME}

Note: Kops create cluster command will result into a configuration file for what your cluster is going tro look like

Important: Important to verify that everything is the way kops expects.

• kops edit cluster cluster-name

Kops update command

• kops update cluster cluster-name

Build the cluster per spec

Check to see if everything is good.

• kubectl get nodes alert when nodes are ready
• kops validate cluster verify that everything works
• You can use terraform to provison that nodes. (Read more terraform)

Microservices

Microservices: An oriented architecture that structures the entire application as a collection of loosely coupled services.