Skip to content

Latest commit

 

History

History
128 lines (96 loc) · 5.07 KB

deploy-sample-application.md

File metadata and controls

128 lines (96 loc) · 5.07 KB
Raw

Deploy our Coffee and Tea Application

A Kubernetes manifest file defines the desired state for the cluster, such as what container images to run, replica count, resource limits, and much more. In this demo, a manifest specifies all objects needed to run the coffee and tea applications.

We have a preconfigured manifest that includes two Kubernetes deployments

  • one for the coffee application and the other for a tea application; both are simply NGINX web servers presenting a web page. Two Kubernetes Services are also created, one for each application, a service is a logical group of a set of pods together and provide network connectivity. A service keeps track of Pod Endpoints (IP address and ports) we can connect to.
  1. Make sure you have the Kubernetes command-line tool, kubectl, to run commands against Kubernetes clusters: See Install and Set Up kubectl

You can use kubectl to deploy applications, inspect and manage cluster resources, and view logs. For a complete list of kubectl operations, see Overview of kubectl.

For example, Installing on linux:

curl -LO https://storage.googleapis.com/kubernetes-release/release/`curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt`/bin/linux/amd64/kubectl
chmod +x ./kubectl
mv ./kubectl /usr/local/bin/kubectl
  1. Review the the deployments/cafe-app/cafe-app.ymlmanifest file

Noteworthy points about the cafe-app.yml manifest:

  • It contains both Deployment and Service specification in the same file for coffee and tea applications.
  • They are deployed in the cafe namespace.
  • These sections are separated by the --- characters, which indicates the start of a document. All YAML files can optionally begin with --- and end with ... to mark the start and end of a document.
  1. Create the cafe namespace, our "virtual cluster" where we deploy our coffee and tea application. Run the kubectl apply to create our cafe namespace defined in a manifest file and run kubectl get to display one or many resources
# Create namespace
kubectl create -f deployments/cafe-app/cafe-namespace.yml

# Check that its exists in our cluster
kubectl get namespaces
NAME              STATUS   AGE
cafe              Active   10s  #<-- There it is!
default           Active   175m
kube-node-lease   Active   175m
kube-public       Active   175m
kube-system       Active   175m
  1. Now that our cafe namespace exists, we can run the kubectl apply again, this time to deploy the coffee and tea deployments and services on to our cluster. We can run kubectl get again to display one or many resources we have deployed in the cafe namespace
# Create Coffee and Tea deployment and service
kubectl apply -f deployments/cafe-app/cafe-app.yml

deployment.apps/coffee created
service/coffee-svc created
deployment.apps/tea created
service/tea-svc created

# Get deployments,services in the cafe namespace
kubectl get pods,deployments,services -n cafe

NAME                          READY   STATUS    RESTARTS   AGE
pod/coffee-74c98dd7c8-kvs2b   1/1     Running   0          2m48s
pod/tea-7dcd6f57b6-kztrd      1/1     Running   0          2m48s

NAME                     READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/coffee   1/1     1            1           2m50s
deployment.apps/tea      1/1     1            1           2m49s

NAME                 TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE
service/coffee-svc   ClusterIP   10.100.104.173   <none>        80/TCP    2m49s
service/tea-svc      ClusterIP   10.100.23.145    <none>        80/TCP    2m49s

READY and AVAILABLE 1/1 and STATUS Running reassure us that everything is working OK!

Scaling the deployment

  1. To Scale out the coffee and tea deployments to multiple pods, we can edit the manifest yaml file and reapply the config or simply with a commandline:
kubectl scale deployments/tea --replicas=3 -n cafe
kubectl scale deployments/coffee --replicas=4 -n cafe
  1. Run the kubectl get command with -o wide option to see which Kubernetes worker nodes the coffee and tea pods were deployed on

Since we have deployed four coffee pods, we can see that one worker node is hosting two pods

kubectl get pods,deployments,services -n cafe -o wide