github.com/qsunny/k8s@v0.0.0-20220101153623-e6dca256d5bf/examples-master/staging/javaee/README.md (about) 1 ## Java EE Application using WildFly and MySQL 2 3 The following document describes the deployment of a Java EE application using [WildFly](http://wildfly.org) application server and MySQL database server on Kubernetes. The sample application source code is at: https://github.com/javaee-samples/javaee7-simple-sample. 4 5 ### Prerequisites 6 7 https://github.com/kubernetes/kubernetes/blob/master/docs/user-guide/prereqs.md 8 9 ### Start MySQL Pod 10 11 In Kubernetes a [_Pod_](https://kubernetes.io/docs/user-guide/pods.md) is the smallest deployable unit that can be created, scheduled, and managed. It's a collocated group of containers that share an IP and storage volume. 12 13 Here is the config for MySQL pod: [mysql-pod.yaml](mysql-pod.yaml) 14 15 <!-- BEGIN MUNGE: mysql-pod.yaml --> 16 <!-- END MUNGE: EXAMPLE --> 17 18 Create the MySQL pod: 19 20 ```sh 21 kubectl create -f examples/javaee/mysql-pod.yaml 22 ``` 23 24 Check status of the pod: 25 26 ```sh 27 kubectl get -w po 28 NAME READY STATUS RESTARTS AGE 29 mysql-pod 0/1 Pending 0 4s 30 NAME READY STATUS RESTARTS AGE 31 mysql-pod 0/1 Running 0 44s 32 mysql-pod 1/1 Running 0 44s 33 ``` 34 35 Wait for the status to `1/1` and `Running`. 36 37 ### Start MySQL Service 38 39 We are creating a [_Service_](https://kubernetes.io/docs/user-guide/services.md) to expose the TCP port of the MySQL server. A Service distributes traffic across a set of Pods. The order of Service and the targeted Pods does not matter. However Service needs to be started before any other Pods consuming the Service are started. 40 41 In this application, we will use a Kubernetes Service to provide a discoverable endpoints for the MySQL endpoint in the cluster. MySQL service target pods with the labels `name: mysql-pod` and `context: docker-k8s-lab`. 42 43 Here is definition of the MySQL service: [mysql-service.yaml](mysql-service.yaml) 44 45 <!-- BEGIN MUNGE: mysql-service.yaml --> 46 <!-- END MUNGE: EXAMPLE --> 47 48 Create this service: 49 50 ```sh 51 kubectl create -f examples/javaee/mysql-service.yaml 52 ``` 53 54 Get status of the service: 55 56 ```sh 57 kubectl get -w svc 58 NAME LABELS SELECTOR IP(S) PORT(S) 59 kubernetes component=apiserver,provider=kubernetes <none> 10.247.0.1 443/TCP 60 mysql-service context=docker-k8s-lab,name=mysql-pod context=docker-k8s-lab,name=mysql-pod 10.247.63.43 3306/TCP 61 ``` 62 63 If multiple services are running, then it can be narrowed by specifying labels: 64 65 ```sh 66 kubectl get -w po -l context=docker-k8s-lab,name=mysql-pod 67 NAME READY STATUS RESTARTS AGE 68 mysql-pod 1/1 Running 0 4m 69 ``` 70 71 This is also the selector label used by service to target pods. 72 73 When a Service is run on a node, the kubelet adds a set of environment variables for each active Service. It supports both Docker links compatible variables and simpler `{SVCNAME}_SERVICE_HOST` and `{SVCNAME}_SERVICE_PORT` variables, where the Service name is upper-cased and dashes are converted to underscores. 74 75 Our service name is ``mysql-service'' and so ``MYSQL_SERVICE_SERVICE_HOST'' and ``MYSQL_SERVICE_SERVICE_PORT'' variables are available to other pods. This host and port variables are then used to create the JDBC resource in WildFly. 76 77 ### Start WildFly Replication Controller 78 79 WildFly is a lightweight Java EE 7 compliant application server. It is wrapped in a Replication Controller and used as the Java EE runtime. 80 81 In Kubernetes a [_Replication Controller_](https://kubernetes.io/docs/concepts/workloads/controllers/replicationcontroller/) is responsible for replicating sets of identical pods. Like a _Service_ it has a selector query which identifies the members of it's set. Unlike a service it also has a desired number of replicas, and it will create or delete pods to ensure that the number of pods matches up with it's desired state. 82 83 Here is definition of the MySQL service: [wildfly-rc.yaml](wildfly-rc.yaml). 84 85 <!-- BEGIN MUNGE: wildfly-rc.yaml --> 86 <!-- END MUNGE: EXAMPLE --> 87 88 Create this controller: 89 90 ```sh 91 kubectl create -f examples/javaee/wildfly-rc.yaml 92 ``` 93 94 Check status of the pod inside replication controller: 95 96 ```sh 97 kubectl get po 98 NAME READY STATUS RESTARTS AGE 99 mysql-pod 1/1 Running 0 1h 100 wildfly-rc-w2kk5 1/1 Running 0 6m 101 ``` 102 103 ### Access the application 104 105 Get IP address of the pod: 106 107 ```sh 108 kubectl get -o template po wildfly-rc-w2kk5 --template={{.status.podIP}} 109 10.246.1.23 110 ``` 111 112 Log in to node and access the application: 113 114 ```sh 115 vagrant ssh node-1 116 Last login: Thu Jul 16 00:24:36 2015 from 10.0.2.2 117 [vagrant@kubernetes-node-1 ~]$ curl http://10.246.1.23:8080/employees/resources/employees/ 118 <?xml version="1.0" encoding="UTF-8" standalone="yes"?><collection><employee><id>1</id><name>Penny</name></employee><employee><id>2</id><name>Sheldon</name></employee><employee><id>3</id><name>Amy</name></employee><employee><id>4</id><name>Leonard</name></employee><employee><id>5</id><name>Bernadette</name></employee><employee><id>6</id><name>Raj</name></employee><employee><id>7</id><name>Howard</name></employee><employee><id>8</id><name>Priya</name></employee></collection> 119 ``` 120 121 ### Delete resources 122 123 All resources created in this application can be deleted: 124 125 ```sh 126 kubectl delete -f examples/javaee/mysql-pod.yaml 127 kubectl delete -f examples/javaee/mysql-service.yaml 128 kubectl delete -f examples/javaee/wildfly-rc.yaml 129 ``` 130 131 132 <!-- BEGIN MUNGE: GENERATED_ANALYTICS --> 133 []() 134 <!-- END MUNGE: GENERATED_ANALYTICS -->