Guidance

• Twelve-Factor App

Kubernetes, Terraform, Helm

This page will list Kubernetes, Terraform, and Helm tips and tricks.

This is the stack that I have used at a couple of companies and it has some great features:

• Rolling updates of new code to pods. Guide: Performing a Rolling Update
• Fast release rollbacks with Helm. Guide: Helm Rollback
• Environment variables management with Kubernetes ConfigMap

View the config map

kubectl get configmaps -n <namespace>

Environment variables may be stored in the config map

kubectl get cm <key> -n <namespace>

To format the content for easier viewing:

kubectl get cm <key> -n <namespace> -o json | jq

View the context

• kubectl config current-context
• kubectl config get-contexts
• kubectl config use-context <context-name>

Restart deployment

Rolling restart of the pods

kubectl rollout restart deploy -n <namespace> <name>

Quick Rollbacks

With Helm, we can roll back a release quickly.

helm rollback <release> -n <namespace>

More Helm

• helm list
• helm history monolith -n <namespace>
• helm lint https://helm.sh/docs/helm/helm_lint/

Get Pods

kubectl get pods -n <namepsace>

kubectl exec -it deployment/<deployment-name> -n <namespace-name> -- bundle exec rails console

Rails console on pod

kubectl -it exec -n <namespace> <podname> -- bundle exec rails c

Kubernetes Jobs

Check the history of deployments:

kubectl rollout history deployment/frontend

Restart specific services:

kubectl rollout restart deploy -n <namespace> sidekiq kubectl rollout restart deploy -n <namespace> <deployment-name>

Scale a deployment:

kubectl scale deployment <deployment-name> --replicas=2 -n service

Jobs

• Jobs may be expressed in a yaml file
• Jobs may be invoked like: kubectl apply -f /Users/anatki/Projects/project/some_cool_job.yaml -n <namespace>

Terraform

terraform login (get set up with terraform cloud) terraform init terraform plan (create the plan)