{"id":817,"date":"2020-03-30T20:00:00","date_gmt":"2020-03-30T20:00:00","guid":{"rendered":"http:\/\/bullyrooks.com\/index.php\/2020\/04\/10\/simple-spring-boot-service-to-kubernetes-application-step-20-fe28a586cdc6\/"},"modified":"2021-02-04T02:16:49","modified_gmt":"2021-02-04T02:16:49","slug":"simple-spring-boot-service-to-kubernetes-application-step-20-fe28a586cdc6","status":"publish","type":"post","link":"https:\/\/bullyrooks.com\/index.php\/2020\/03\/30\/simple-spring-boot-service-to-kubernetes-application-step-20-fe28a586cdc6\/","title":{"rendered":"Creating an Ingress in Kubernetes"},"content":{"rendered":"\n
We\u2019ve got multiple service available for deployment now. Lets allow them to communicate internally and externally with the cluster. We\u2019ll do that by creating an ingress.<\/p>\n\n\n\n
Current State of Our Application<\/h3>\n\n\n\n<\/figure>\n\n\n\n
We\u2019re using our services as nodeports which allows us to expose an external port that will map to the internal port used by the the application. From our helm configuration our services start up on their default port (spring=8080, nginx=80) but that gets mapped to port 80 internally. So if we were inside our cluster we could talk to customer manager directly by calling its service on port 80. When we\u2019re external we have to use port 30002.<\/p>\n\n\n\n
This works okay when we\u2019re running externally on our development machine, but is terrible for production. For one, keeping track of the cluster IP and making sure that each service is calling the correct port can be a maintenance nightmare.<\/p>\n\n\n\n
Using an Ingress<\/h3>\n\n\n\n<\/figure>\n\n\n\n
We\u2019re going to install another component called an ingress which acts like an api gateway. This allows us to only talk to a single IP and port combination to access all components within our application. We can still access services directly via their external port (for testing, etc\u2026) but the most important part is that our front-end application won\u2019t need to know anything about where our services live and how to access them. The ingress takes care of that.<\/p>\n\n\n\n
Creating an Ingress<\/h3>\n\n\n\n
Create a new git repository called medium-ingress<\/code>. Clone that locally and in that repo create a directory called helm<\/code>. In here use helm create medium-ingress<\/code> to initialize the chart. We\u2019re going to strip out all of the files since we really only need 3.<\/p>\n\n\n\n
apiVersion: v1\nname: medium-ingress\ndescription: The ingress into the medium application\n\ntype: application\nversion: 0.1.0\nappVersion: 1.16.0<\/code><\/pre>\n\n\n\n
values.yaml<\/code> can be left empty<\/p>\n\n\n\n
The important part is the ingress deployment descriptor. In here we\u2019re creating the mapping of the request path to the internal kubernetes service name and port. I just realized that my names are not very clean and I should fix that but this will get us going.<\/p><\/blockquote>\n\n\n\n
Minikube Setup<\/h3>\n\n\n\n
We need to do some things first before we can deploy. Ingress is a definition, but it is actually implemented within the kubernetes cluster and there are lots of implementations to choose from. We\u2019re going to use the basic ingress for minikube, but we need to install it first.<\/p>\n\n\n\n
kubectl get pods -n ingress-nginx<\/code><\/pre>\n\n\n\n
We also want to update our hosts file to add a mapping for medium-example.com<\/code> to our minikube ip (which can be retrieved via minikube ip<\/code>). This is partly for ease of use for us, but also important because the ingress controller uses the domain for mapping.<\/p>\n\n\n\n
...\n172.18.51.82 medium-example.com\n# End of section<\/code><\/pre>\n\n\n\n
Update Frontend<\/h3>\n\n\n\n
We have one more minor change to make to our react frontend. Change helm\/medium-customer-manager\/values.yaml<\/code> to stop calling the customer service via external port<\/p>\n\n\n\n
config:\n## Currently only supports file\n<\/em>type: file\n## Contents of config in YAML\n<\/em>content: |-\n window.REACT_APP_CUSTOMER_HOST=''<\/code><\/pre>\n\n\n\n
Go ahead and commit this to kick off a build<\/p>\n\n\n\n
![\"\"](\"https:\/\/i0.wp.com\/bullyrooks.com\/wp-content\/uploads\/2021\/02\/1fJU_c0QZxDuMCzwrr2ue5g.png?w=960\")
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