OpenShift – 入门
OpenShift – 入门
OpenShift 包含两种类型的中位数来创建和部署应用程序，通过 GUI 或通过 CLI。在本章中，我们将使用 CLI 创建一个新应用程序。我们将使用 OC 客户端与 OpenShift 环境进行通信。
创建新应用程序
在 OpenShift 中，有三种创建新应用程序的方法。
- 从源代码
- 从图像
- 从模板
从源代码
当我们尝试从源代码创建应用程序时，OpenShift 会查找存储库中应该存在的 Docker 文件，该文件定义了应用程序构建流程。我们将使用 oc new-app 创建一个应用程序。
使用 repo 时要记住的第一件事是，它应该指向 repo 中的一个来源，OpenShift 将从那里提取代码并构建它。
如果 repo 是在安装了 OC 客户端的 Docker 机器上克隆的，并且用户在同一目录中，则可以使用以下命令创建它。
$ oc new-app . <Hear. Denotes current working directory>
以下是尝试从远程仓库为特定分支构建的示例。
$ oc new-app https://github.com/openshift/Testing-deployment.git#test1
在这里，test1 是我们尝试在 OpenShift 中创建新应用程序的分支。
在存储库中指定 Docker 文件时，我们需要定义构建策略，如下所示。
$ oc new-app OpenShift/OpenShift-test~https://github.com/openshift/Testingdeployment.git
从图像
在使用图像构建应用程序时，图像存在于本地 Docker 服务器、内部托管的 Docker 存储库或 Docker 集线器中。用户唯一需要确保的是，他可以毫无问题地从集线器中提取图像。
OpenShift 能够确定使用的源，无论是 Docker 镜像还是源流。但是，如果用户愿意，他可以明确定义它是镜像流还是 Docker 镜像。
$ oc new-app - - docker-image tomcat
使用图像流 –
$ oc new-app tomcat:v1
从模板
模板可用于创建新应用程序。它可以是已经存在的模板，也可以是创建新模板。
下面的 yaml 文件基本上是一个可以用于部署的模板。
apiVersion: v1
kind: Template
metadata:
name: <Name of template>
annotations:
description: <Description of Tag>
iconClass: "icon-redis"
tags: <Tages of image>
objects:
- apiVersion: v1
kind: Pod
metadata:
name: <Object Specification>
spec:
containers:
image: <Image Name>
name: master
ports:
- containerPort: <Container port number>
protocol: <Protocol>
labels:
redis: <Communication Type>
开发和部署 Web 应用程序
在 OpenShift 中开发新应用程序
为了在 OpenShift 中创建新应用程序，我们必须编写新的应用程序代码并使用 OpenShift OC 构建命令构建它。如前所述，我们有多种创建新图像的方法。在这里，我们将使用模板来构建应用程序。当使用 oc new-app 命令运行时，此模板将构建一个新应用程序。
以下模板将创建 – 两个前端应用程序和一个数据库。与此同时，它将创建两个新服务，这些应用程序将被部署到 OpenShift 集群。在构建和部署应用程序时，最初我们需要在 OpenShift 中创建一个命名空间并将应用程序部署在该命名空间下。
创建一个新的命名空间
$ oc new-project openshift-test --display-name = "OpenShift 3 Sample" -- description = "This is an example project to demonstrate OpenShift v3"
模板
{
"kind": "Template",
"apiVersion": "v1",
"metadata": {
"name": "openshift-helloworld-sample",
"creationTimestamp": null,
"annotations": {
"description": "This example shows how to create a simple openshift
application in openshift origin v3",
"iconClass": "icon-openshift",
"tags": "instant-app,openshift,mysql"
}
}
},
对象定义
模板中的秘密定义
"objects": [
{
"kind": "Secret",
"apiVersion": "v1",
"metadata": {"name": "dbsecret"},
"stringData" : {
"mysql-user" : "${MYSQL_USER}",
"mysql-password" : "${MYSQL_PASSWORD}"
}
},
模板中的服务定义
{
"kind": "Service",
"apiVersion": "v1",
"metadata": {
"name": "frontend",
"creationTimestamp": null
},
"spec": {
"ports": [
{
"name": "web",
"protocol": "TCP",
"port": 5432,
"targetPort": 8080,
"nodePort": 0
}
],
"selector": {"name": "frontend"},
"type": "ClusterIP",
"sessionAffinity": "None"
},
"status": {
"loadBalancer": {}
}
},
模板中的路由定义
{
"kind": "Route",
"apiVersion": "v1",
"metadata": {
"name": "route-edge",
"creationTimestamp": null,
"annotations": {
"template.openshift.io/expose-uri": "http://{.spec.host}{.spec.path}"
}
},
"spec": {
"host": "www.example.com",
"to": {
"kind": "Service",
"name": "frontend"
},
"tls": {
"termination": "edge"
}
},
"status": {}
},
{
"kind": "ImageStream",
"apiVersion": "v1",
"metadata": {
"name": "origin-openshift-sample",
"creationTimestamp": null
},
"spec": {},
"status": {
"dockerImageRepository": ""
}
},
{
"kind": "ImageStream",
"apiVersion": "v1",
"metadata": {
"name": "openshift-22-ubuntu7",
"creationTimestamp": null
},
"spec": {
"dockerImageRepository": "ubuntu/openshift-22-ubuntu7"
},
"status": {
"dockerImageRepository": ""
}
},
在模板中构建配置定义
{
"kind": "BuildConfig",
"apiVersion": "v1",
"metadata": {
"name": "openshift-sample-build",
"creationTimestamp": null,
"labels": {name": "openshift-sample-build"}
},
"spec": {
"triggers": [
{ "type": "GitHub",
"github": {
"secret": "secret101" }
},
{
"type": "Generic",
"generic": {
"secret": "secret101",
"allowEnv": true }
},
{
"type": "ImageChange",
"imageChange": {}
},
{ "type": "ConfigChange”}
],
"source": {
"type": "Git",
"git": {
"uri": https://github.com/openshift/openshift-hello-world.git }
},
"strategy": {
"type": "Docker",
"dockerStrategy": {
"from": {
"kind": "ImageStreamTag",
"name": "openshift-22-ubuntu7:latest”
},
"env": [
{
"name": "EXAMPLE",
"value": "sample-app"
}
]
}
},
"output": {
"to": {
"kind": "ImageStreamTag",
"name": "origin-openshift-sample:latest"
}
},
"postCommit": {
"args": ["bundle", "exec", "rake", "test"]
},
"status": {
"lastVersion": 0
}
}
},
模板中的部署配置
"status": {
"lastVersion": 0
}
{
"kind": "DeploymentConfig",
"apiVersion": "v1",
"metadata": {
"name": "frontend",
"creationTimestamp": null
}
},
"spec": {
"strategy": {
"type": "Rolling",
"rollingParams": {
"updatePeriodSeconds": 1,
"intervalSeconds": 1,
"timeoutSeconds": 120,
"pre": {
"failurePolicy": "Abort",
"execNewPod": {
"command": [
"/bin/true"
],
"env": [
{
"name": "CUSTOM_VAR1",
"value": "custom_value1"
}
]
}
}
}
}
}
"triggers": [
{
"type": "ImageChange",
"imageChangeParams": {
"automatic": true,
"containerNames": [
"openshift-helloworld"
],
"from": {
"kind": "ImageStreamTag",
"name": "origin-openshift-sample:latest"
}
}
},
{
"type": "ConfigChange"
}
],
"replicas": 2,
"selector": {
"name": "frontend"
},
"template": {
"metadata": {
"creationTimestamp": null,
"labels": {
"name": "frontend"
}
},
"spec": {
"containers": [
{
"name": "openshift-helloworld",
"image": "origin-openshift-sample",
"ports": [
{
"containerPort": 8080,
"protocol": "TCP”
}
],
"env": [
{
"name": "MYSQL_USER",
"valueFrom": {
"secretKeyRef" : {
"name" : "dbsecret",
"key" : "mysql-user"
}
}
},
{
"name": "MYSQL_PASSWORD",
"valueFrom": {
"secretKeyRef" : {
"name" : "dbsecret",
"key" : "mysql-password"
}
}
},
{
"name": "MYSQL_DATABASE",
"value": "${MYSQL_DATABASE}"
}
],
"resources": {},
"terminationMessagePath": "/dev/termination-log",
"imagePullPolicy": "IfNotPresent",
"securityContext": {
"capabilities": {},
"privileged": false
}
}
],
"restartPolicy": "Always",
"dnsPolicy": "ClusterFirst"
},
"status": {}
},
模板中的服务定义
{
"kind": "Service",
"apiVersion": "v1",
"metadata": {
"name": "database",
"creationTimestamp": null
},
"spec": {
"ports": [
{
"name": "db",
"protocol": "TCP",
"port": 5434,
"targetPort": 3306,
"nodePort": 0
}
],
"selector": {
"name": "database
},
"type": "ClusterIP",
"sessionAffinity": "None" },
"status": {
"loadBalancer": {}
}
},
模板中的部署配置定义
{
"kind": "DeploymentConfig",
"apiVersion": "v1",
"metadata": {
"name": "database",
"creationTimestamp": null
},
"spec": {
"strategy": {
"type": "Recreate",
"resources": {}
},
"triggers": [
{
"type": "ConfigChange"
}
],
"replicas": 1,
"selector": {"name": "database"},
"template": {
"metadata": {
"creationTimestamp": null,
"labels": {"name": "database"}
},
"template": {
"metadata": {
"creationTimestamp": null,
"labels": {
"name": "database"
}
},
"spec": {
"containers": [
{
"name": "openshift-helloworld-database",
"image": "ubuntu/mysql-57-ubuntu7:latest",
"ports": [
{
"containerPort": 3306,
"protocol": "TCP"
}
],
"env": [
{
"name": "MYSQL_USER",
"valueFrom": {
"secretKeyRef" : {
"name" : "dbsecret",
"key" : "mysql-user"
}
}
},
{
"name": "MYSQL_PASSWORD",
"valueFrom": {
"secretKeyRef" : {
"name" : "dbsecret",
"key" : "mysql-password"
}
}
},
{
"name": "MYSQL_DATABASE",
"value": "${MYSQL_DATABASE}"
}
],
"resources": {},
"volumeMounts": [
{
"name": "openshift-helloworld-data",
"mountPath": "/var/lib/mysql/data"
}
],
"terminationMessagePath": "/dev/termination-log",
"imagePullPolicy": "Always",
"securityContext": {
"capabilities": {},
"privileged": false
}
}
],
"volumes": [
{
"name": "openshift-helloworld-data",
"emptyDir": {"medium": ""}
}
],
"restartPolicy": "Always",
"dnsPolicy": "ClusterFirst”
}
}
},
"status": {}
},
"parameters": [
{
"name": "MYSQL_USER",
"description": "database username",
"generate": "expression",
"from": "user[A-Z0-9]{3}",
"required": true
},
{
"name": "MYSQL_PASSWORD",
"description": "database password",
"generate": "expression",
"from": "[a-zA-Z0-9]{8}",
"required": true
},
{
"name": "MYSQL_DATABASE",
"description": "database name",
"value": "root",
"required": true
}
],
"labels": {
"template": "application-template-dockerbuild"
}
}
上述模板文件需要一次性编译。我们需要首先将所有内容复制到一个文件中，完成后将其命名为 yaml 文件。
我们需要运行以下命令来创建应用程序。
$ oc new-app application-template-stibuild.json
--> Deploying template openshift-helloworld-sample for "application-template-stibuild.json"
openshift-helloworld-sample
---------
This example shows how to create a simple ruby application in openshift origin v3
* With parameters:
* MYSQL_USER = userPJJ # generated
* MYSQL_PASSWORD = cJHNK3se # generated
* MYSQL_DATABASE = root
--> Creating resources with label app = ruby-helloworld-sample ...
service "frontend" created
route "route-edge" created
imagestream "origin-ruby-sample" created
imagestream "ruby-22-centos7" created
buildconfig "ruby-sample-build" created
deploymentconfig "frontend" created
service "database" created
deploymentconfig "database" created
--> Success
Build scheduled, use 'oc logs -f bc/ruby-sample-build' to track its progress.
Run 'oc status' to view your app.
如果我们希望监控构建，可以使用 –
$ oc get builds NAME TYPE FROM STATUS STARTED DURATION openshift-sample-build-1 Source Git@bd94cbb Running 7 seconds ago 7s
我们可以使用以下方法检查 OpenShift 上部署的应用程序 –
$ oc get pods NAME READY STATUS RESTARTS AGE database-1-le4wx 1/1 Running 0 1m frontend-1-e572n 1/1 Running 0 27s frontend-1-votq4 1/1 Running 0 31s opeshift-sample-build-1-build 0/1 Completed 0 1m
我们可以使用以下方法检查应用程序服务是否是按照服务定义创建的
$ oc get services NAME CLUSTER-IP EXTERNAL-IP PORT(S) SELECTOR AGE database 172.30.80.39 <none> 5434/TCP name=database 1m frontend 172.30.17.4 <none> 5432/TCP name=frontend 1m
