Microservice Kubernetes Order Processing Application

Overview

This project creates a complete micro service demo system in Docker containers. The services are implemented in Java using Spring and Spring Cloud.

It uses four docker microservices:

• Apache homepage and proxy
• Order to process orders.
• Customer to handle customer data.
• Catalog to handle the items in the catalog.

Components

Apache HTTP Load Balancer

Apache HTTP is used to provide the web page of the demo at port 8080. It also forwards HTTP requests to the microservices. This is not really necessary as each service has its own port on the Minikube host but it provides a single point of entry for the whole system. Apache HTTP is configured as a reverse proxy for this. Load balancing is left to Kubernetes.

To configure this Apache HTTP needs to get all registered services from Kubernetes. It just uses DNS for that.

Please refer to the subdirectory microservice-kubernetes-demo/apache to see how this works.

Java Services

The microservices are:

• microservice-kubernetes-demo-catalog is the application to take care of items.
• microservice-kubernetes-demo-customer is responsible for customers.
• microservice-kubernetes-demo-order does order processing. It uses microservice-kubernetes-demo-catalog and microservice-kubernetes-demo-customer.

The microservices use REST to communicate to each other. See e.g. CatalogClient . The hostname is configurable to allow tests with stubs. The default is catalog which works with Kubernetes. Other microservices are found using Kubernetes built-in DNS. Kubernetes does the load balancing on the IP level.

Install/Prepare to run the demo

AWS

1. AWS account
2. AWS IAM user - Note this user will need some IAM permissions including roles, policies, OpenID

Install the AWS CLI

1. Install
2. Configure

% aws --version
aws-cli/2.11.5 Python/3.11.2 Darwin/22.3.0 exe/x86_64 prompt/off

% aws sts get-caller-identity
{
    "UserId": "YYA4ZRSAMPLE6IDAGV2YP",
    "Account": "378929636692",
    "Arn": "arn:aws:iam::378929636692:user/dockerbisson"
}

Tools to install on new laptop

1. Install brew:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

2. Install helm: brew install helm
3. Install jq: brew install jq

Terraform Cloud

1. Create account
2. Create an org - use the org name in the terraform.tf file
3. Terraform variables with AWS credentials

Terraform local

From the top level of the repo

1. brew install terraform (first time install only )
2. terraform init
3. terraform plan
4. time terraform apply -auto-approve

kubectl config

Get kubectl config (more details):

aws eks --region us-east-1 update-kubeconfig --name demo-eks

The region and name values match those in the main.tf file.

Build the images

1. Log in to your Docker Hub account by entering docker login on the command line.
2. Set the environment variable DOCKER_ACCOUNT to the name of the account and verify it with echo.

export DOCKER_ACCOUNT=your account
echo $DOCKER_ACCOUNT

3. If you are running on x86, run docker-build.sh in the directory microservice-kubernetes-demo. It builds the images and uploads them to Docker Hub using your account.

3a. If you are running on arm64 (apple silicon), you will need to build images for arm64 and amd64 and push to hub using buildx. Change to the directory microservice-kubernetes-demo and run ./docker-buildx.sh

Deploy to EKS

Run ./kubernetes-deploy.sh in the directory microservice-kubernetes-demo :

[~/microservice-kubernetes/microservice-kubernetes-demo]./kubernetes-deploy.sh
deployment "apache" created
service "apache" exposed
deployment "catalog" created
service "catalog" exposed
deployment "customer" created
service "customer" exposed
deployment "order" created
service "order" exposed

Confirm the services are running using kubectl

kubectl get all

Confirm the app is running in EKS (may take a minute or two for the app to be running)

open "http://$(kubectl get service -o json | jq -r '.items[0].status.loadBalancer.ingress[].hostname')"

Browser setup (optional, can use preview URL instead)

1. Install the mod header extension for chrome

Telepresence extension setup (required for GUI or spec intercepts)

1. Open Docker Desktop
2. Install telepresence extension

REQUIRED if you are going to demo the intercept spec method

1. Update the kubernetes context in the apache-intercept.yaml and order-intercept.yaml files in the microservice-kubernetes directory - get it from kubectl

kubectl config current-context

Demo Execution

---

Front end demo

Show the app running in EKS, show the homepage is missing the logo and has two links with the same name

Update the index.html page to add the telepresence logo and change the link text for the second catalog link and build the image

1. cd to the microservice-kubernetes-demo/apache directory
2. Open the index.html file
3. Add the telepresence logo image (changes are bolded)

<body>

<img src="images/telepresence-for-docker.svg"/>

	<h1>Order Processing</h1>

4. change the second catalog link in index.html and save(changes have ** around them)

				<a href="/catalog/searchForm.html">**Search** Catalog</a>

5. Run docker build --tag=microservice-kubernetes-demo-apache .

IMPORTANT - the Spec, GUI and CLI telepresence intercept options are separate. You can do each of them, but you need to make sure the intercept is down before switching between them. Please make sure you click the "disconnect/leave" icon when you are switching between these options

(spec option only)Docker desktop and telepresence create intercept

1. Open Docker Desktop
2. Go to the telepresence extension
3. Select "Get Started" - the Select Cluster for Telepresence Connection Dialog will appear
4. The kubeconfig context should show the aws cluster
5. Select "Install telepresence on this cluster" only if this is the first connection since building the cluster
6. Select the down arrow next to the connect button, upload intercept spec should display
7. Select the apache-intercept.yaml file in the microservice-kubernetes-demo folder
8. Telepresence will start the intercept with the image specified in the intercept file
9. There may be a warning message show up in a pop up from the container, you can ignore this and close it

(GUI option only) Docker desktop and telepresence setup

1. Open Docker Desktop
2. Go to the telepresence extension
3. Select "Get Started" - the Select Cluster for Telepresence Connection Dialog will appear
4. The kubeconfig context should show the aws cluster
5. Select "Install telepresence on this cluster" only if this is the first connection since building the cluster
6. Select connect
7. The default namespace should pop
8. The four services service should be listed
9. Click Intercept next to the Apache service
10. A dialog appears for the Intercept
11. Make sure the target docker image is microservice-kubernetes-demo-apache:latest
12. Both the Service Port Number and the Target Port Number are 80
13. Leave the other settings
14. Click Create Intercept
15. There may be a warning message show up in a pop up from the container, you can ignore this and close it

(CLI option only) Telepresence connect and creating the intercept

1. Type telepresence intercept --docker apache --port 80:80 --docker-run -- -it --rm microservice-kubernetes-demo-apache:latest

Show the container running(optional)

1. Go to the containers tab
2. Show there is a tp-apache or intercept-apache container running
3. Explain that the telepresence extension runs this container when the intercept starts based on the image you specify

Showing the intercept

Option 1: HTTP headers

1. Copy the request header string shown in the current running intercepts (or on the terminal page)
2. Put the x-telepresence-intercept-id in the name field in mod header
3. Put the rest (minus the colon after id) into the value field and make sure the green check is there
4. Refresh the order processing homepage page to see the new image and link text
5. Turn off the header and show the unchanged page

Option 2: Preview URL

1. Click the preview URL link (or copy from the terminal page), put it in a new tab, and show the updated page
2. Refresh the original tab to show the unchanged page

(GUI) Stop the intercept

1. Click stop intercept
2. (optional) show the local container has stopped as well
3. You may need to click the "leave" icon in the upper right to get back to the connect/startpage in the telepresence extension - there may also be a warning message, you can ignore it.

(CLI) Stop the intercept

1. type 'telepresence leave' (note this may not be required if you control C the telepresence command)

---

Back End Demo

1. Show the app running in EKS, go to the orders page - there are no orders.
2. Create an order, add a line with a quantity, and hit submit.
3. Click list to see the order
4. Click delete next to the order
5. Get an error that the method is not allowed

Update the Java code to fix the error and build the image

1. cd to the microservice-kubernetes-demo/microservice-kubernetes-demo-order/src/main/java/com/ewolff/microservice/order/logic directory
2. Open the OrderController.java file
3. Update the method that has "DELETE" in it to POST(change in **)

	@RequestMapping(value = "/{id}", method = RequestMethod.**POST**)
	public ModelAndView post(@PathVariable("id") long id) {
		orderRepository.deleteById(id);

4. save the file
5. cd up to the microservices-kubernetes-demo directory
6. Run ./docker-build-order.sh to recompile and build the image (local only)

IMPORTANT - the Spec, GUI and CLI telepresence intercept options are separate. You can do each of them, but you need to make sure the intercept is down before switching between them.

(spec option only)Docker desktop and telepresence create intercept

1. Open Docker Desktop
2. Go to the telepresence extension
3. Select "Get Started" - the Select Cluster for Telepresence Connection Dialog will appear
4. The kubeconfig context should show the aws cluster
5. Select "Install telepresence on this cluster" only if this is the first connection since building the cluster
6. Select the down arrow next to the connect button, upload intercept spec should display
7. Select the order-intercept.yaml file in the microservice-kubernetes folder
8. Telepresence will start the intercept with the image specified in the intercept file

(GUI option only) Docker desktop and telepresence setup

1. Open Docker Desktop
2. Go to the telepresence extension
3. Select "Get Started" - the Select Cluster for Telepresence Connection Dialog will appear
4. The kubeconfig context should show the aws cluster
5. Select "Install telepresence on this cluster" only if this is the first connection since building the cluster
6. Select connect
7. The default namespace should pop
8. The four services service should be listed
9. Click Intercept next to the Order service
10. A dialog appears for the Intercept
11. Make sure the target docker image is microservice-kubernetes-demo-order:latest
12. Target Port Number is 8080
13. Leave the other settings
14. Click Create Intercept

(CLI option only) Telepresence connect and creating the intercept

1. Type telepresence intercept --docker order --port 8080:8080 --docker-run -- -it --rm microservice-kubernetes-demo-order:latest Note: you will get logging from the Java service, just scroll up to the telepresence output you need

If you receive the following error, telepresence intercept: error: option --docker cannot be used as long as a daemon is running on the host. Try telepresence quit -s try running docker network create --ipv6 --subnet=fd25::/64 --gateway=fd25::1 telepresence

Note: you may need to run telepresence helm upgrade --team-mode

Show the container running(optional)

1. Go to the containers tab
2. Show there is a tp-order container running
3. Explain that the telepresence extension runs this container when the intercept starts based on the image you specify

Showing the intercept

HTTP headers

1. Copy the request header string shown in the current running intercepts (or on the terminal page)
2. Put the x-telepresence-intercept-id in the name field in mod header
3. Put the rest (minus the colon after id) into the value field and make sure the green check is there
4. Go to the orders list - see there are no orders now because the order service has no permament storage
5. Create an order, add a line with a quantity, and hit submit.
6. Click list to see the order
7. Click delete next to the order
8. Delete successful
9. Click list to see the order is gone
10. Turn off header and click list to see original order is there, still can't delete it

(GUI) Stop the intercept

1. Click stop intercept
2. (optional) show the local container has stopped as well

(CLI) Stop the intercept

1. type 'telepresence leave'

Demo cleanup

Change the app back

1. cd to the apache directory
2. Update the index.html file - remove the image link, change the catalog link back and save
3. cd to the microservice-kubernetes-demo/microservice-kubernetes-demo-order/src/main/java/com/ewolff/microservice/order/logic directory
4. Update the OrderController.java file - change the POST back to DELETE on the delete method (make sure you get the right one)

Remove the deployed services

1. cd to the microservices-kubernetes-demo directory
2. To remove all services and deployments run kubernetes-remove.sh:

[~/microservice-kubernetes/microservice-kubernetes-demo]./kubernetes-remove.sh 
service "apache" deleted
service "catalog" deleted
service "customer" deleted
service "order" deleted
deployment "apache" deleted
deployment "catalog" deleted
deployment "customer" deleted
deployment "order" deleted

Verify the app is deleted (only the generic kubernetes service should remain)

kubectl get all 

Change the kubectl context back to Docker desktop

1. type kubectl config use-context docker-desktop

Deleting the infrastructure from AWS

From the top-level of the repo

1. terraform destroy -auto-approve
2. Manually delete any load balancers associated with the cluster in the web console
3. Manually delete the VPC associated with the cluster in the web console
4. terraform destroy -auto-approve again

Clearing DNS cache

If needed...

sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder