In this section you will get a quick taste of all the manual steps needed to turn local application code into a an app running on a Kubernetes cluster. this is not the most efficient or recommended way, but it is necessary if you need to gain deeper understanding into what tools such as Helm and Jenkins offer us when it comes to creating deployable apps and doing continuous delivery.
- Create Kubernetes Config Maps and Secrets for the Todo application
- Create the Todo App on the cluster
You will deploy the application to its own namespace called todo-app.
#Create a namespace to deploy the application, we will use todo-app
kubectl create namespace todo-app
#Run the command
./deploy-todo-app.sh -n todo-app
#get the deployed services to get the external IP to the application
#for ACS or AKS, the -w flag stands for watch; as ACS/AKS will provision
#a load-balancer, it can take some time for the external IP to be provided.
kubectl get services -n todo-app -w
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
mongodb ClusterIP 10.0.43.235 <none> 27017/TCP 2m
todo-api ClusterIP 10.0.214.55 <none> 8080/TCP 2m
todo-app-ui LoadBalancer 10.0.114.41 52.235.45.69 80:32585/TCP 2m
user-api ClusterIP 10.0.144.252 <none> 8082/TCP 2m
#open up a browser and go the IP:port for the todo-app-ui service.
#access the K8S dashboard on AKS to see the deployed resources
az aks browse -n <cluster-name> -g <resource-group>
#on Minikube
minikube dashboardHere is a description of what the script did.
First we create a few secrets based on the secrets directory, you can see that in this directory we store secrets such as the azure ad identity of the app, only the Ops team has access to this secured secret directory
kubectl create secret generic todoapp-secrets --from-file=secrets --namespace=$todoapp_namespaceThe next line will create the configmap from the yaml file, you can check the yaml file to get an idea of the configuration environment variables passed to the application (such as log level and mongoDB url)
kubectl create --namespace=$todoapp_namespace -f todo-ui-config.yaml
kubectl create --namespace=$todoapp_namespace -f todo-api-config.yaml
kubectl create --namespace=$todoapp_namesapce -f user-api-config.yamlFinally we do install the application components using Deployments and Services declared in the todo-app.yaml
kubectl create --namespace=$todoapp_namespace -f todo-app.yamlThis approach makes installing the application in different environments, with different docker repositories and a very complex process. You have to execute multiple commands, many of them similar, there is configuration that is defined in different files but have the same values. Hence, maintaining this deployment will be error prone and with more pods, services and deployments, the complexity will rapidly increase.
Tools such as Helm help manage this complexity. See an example of deploying the same application using Helm in ../../helm
To blow everything away run:
kubectl delete namespace <namespace_name>This will delete your namespace and all resources scoped to that namespace.
Build and push the images to Docker Hub and update the images to pull the images from your registry.
First make sure you have a docker hub id dockerhub-id or sign in to Dockerhub to get one https://hub.docker.com/
Please follow the documentation in the following links to create a repository and create three repositories todo-api, todo-ui and user-api
https://docs.docker.com/docker-hub/repos/#viewing-repository-tags
You can run the following shell script that will build images, tags them and pushes them into your Dockerhub repositories
./build-push-images.sh dockerhub-id
When prompted with the password, enter your DockerHub password and the images will be pushed into your DockerHub and your dashboard will look like this in the web repositories
Open up todo-app.yaml. Update the following lines with your image versions.
image: architechbootcamp/todo-ui:latest
image: architechbootcamp/todo-api:latest
image: architechbootcamp/user-api:latestRedeploy the todo-app with images from your registry.