第 5 章 安装区识别示例应用程序

使用本节来部署区识别示例应用程序，以验证 OpenShift Container Storage Metro Disaster 恢复设置是否正确配置。

重要

随着数据区域之间的延迟，可以预期与节点和区域之间具有低延迟的 OpenShift 集群（例如，同一位置的所有节点）相比，可以看到性能下降。性能会下降多少，取决于区域之间的延迟和使用存储（如高写流量）的应用行为。请确保使用 Metro DR 集群配置测试关键应用程序，以确保应用程序性能达到所需的服务水平。

5.1. 安装区示例应用程序

在本节中，ocs-storagecluster-cephfs 存储类用于创建一个可由多个 pod 同时使用的 Read-Write-Many(RWX)PVC。我们将使用的应用程序称为文件上传程序。

由于此应用共享用于存储文件的 RWX 卷，我们可以演示如何在拓扑区域之间分散应用，以便在站点中断时仍可用。这也适用于持久数据访问，因为 OpenShift Container Storage 被配置为具有区感知和高可用性的 Metro DR 扩展集群。

  1. 创建一个新项目 

    oc new-project my-shared-storage

  2. 部署名为 file-uploader 的 PHP 应用程序示例： 

    oc new-app openshift/php:7.2-ubi8~https://github.com/christianh814/openshift-php-upload-demo --name=file-uploader

    输出示例： 

    Found image 4f2dcc0 (9 days old) in image stream "openshift/php" under tag "7.2-ubi8" for "openshift/php:7.2-
ubi8"

Apache 2.4 with PHP 7.2
-----------------------
PHP 7.2 available as container is a base platform for building and running various PHP 7.2 applications and frameworks. PHP is an HTML-embedded scripting language. PHP attempts to make it easy for developers to write dynamically generated web pages. PHP also offers built-in database integration for several commercial and non-commercial database management systems, so writing a database-enabled webpage with PHP is fairly simple. The most common
use of PHP coding is probably as a replacement for CGI scripts.

Tags: builder, php, php72, php-72

* A source build using source code from https://github.com/christianh814/openshift-php-upload-demo will be cr
eated
* The resulting image will be pushed to image stream tag "file-uploader:latest"
* Use 'oc start-build' to trigger a new build

--> Creating resources ...
    imagestream.image.openshift.io "file-uploader" created
    buildconfig.build.openshift.io "file-uploader" created
    deployment.apps "file-uploader" created
    service "file-uploader" created
--> Success
    Build scheduled, use 'oc logs -f buildconfig/file-uploader' to track its progress.

    Application is not exposed. You can expose services to the outside world by executing one or more of the commands below:
     'oc expose service/file-uploader'

    Run 'oc status' to view your app.

  3. 查看构建日志并等待应用程序部署： 

    oc logs -f bc/file-uploader -n my-shared-storage

    输出示例： 

    Cloning "https://github.com/christianh814/openshift-php-upload-demo" ...

    [...]
    Generating dockerfile with builder image image-registry.openshift-image-regis
try.svc:5000/openshift/php@sha256:d97466f33999951739a76bce922ab17088885db610c
0e05b593844b41d5494ea
STEP 1: FROM image-registry.openshift-image-registry.svc:5000/openshift/php@s
ha256:d97466f33999951739a76bce922ab17088885db610c0e05b593844b41d5494ea
STEP 2: LABEL "io.openshift.build.commit.author"="Christian Hernandez <christ
ian.hernandez@yahoo.com>"       "io.openshift.build.commit.date"="Sun Oct 1 1
7:15:09 2017 -0700"       "io.openshift.build.commit.id"="288eda3dff43b02f7f7
b6b6b6f93396ffdf34cb2"       "io.openshift.build.commit.ref"="master"       "
io.openshift.build.commit.message"="trying to modularize"       "io.openshift
.build.source-location"="https://github.com/christianh814/openshift-php-uploa
d-demo"       "io.openshift.build.image"="image-registry.openshift-image-regi
stry.svc:5000/openshift/php@sha256:d97466f33999951739a76bce922ab17088885db610
c0e05b593844b41d5494ea"
STEP 3: ENV OPENSHIFT_BUILD_NAME="file-uploader-1"     OPENSHIFT_BUILD_NAMESP
ACE="my-shared-storage"     OPENSHIFT_BUILD_SOURCE="https://github.com/christ
ianh814/openshift-php-upload-demo"     OPENSHIFT_BUILD_COMMIT="288eda3dff43b0
2f7f7b6b6b6f93396ffdf34cb2"
STEP 4: USER root
STEP 5: COPY upload/src /tmp/src
STEP 6: RUN chown -R 1001:0 /tmp/src
STEP 7: USER 1001
STEP 8: RUN /usr/libexec/s2i/assemble
---> Installing application source...
=> sourcing 20-copy-config.sh ...
---> 17:24:39     Processing additional arbitrary httpd configuration provide
d by s2i ...
=> sourcing 00-documentroot.conf ...
=> sourcing 50-mpm-tuning.conf ...
=> sourcing 40-ssl-certs.sh ...
STEP 9: CMD /usr/libexec/s2i/run
STEP 10: COMMIT temp.builder.openshift.io/my-shared-storage/file-uploader-1:3
b83e447
Getting image source signatures

[...]

    当您看到 Push successful 后，命令提示符会从 tail 模式返回。

注意

new-app 命令直接从 git 存储库部署应用，而不使用 OpenShift 模板，因此默认情况下不创建 OpenShift 路由资源。我们需要手动创建路线。

通过将应用程序区扩展到 4 个副本并公开其服务，让应用程序区了解并可用： 

oc expose svc/file-uploader -n my-shared-storage
oc scale --replicas=4 deploy/file-uploader -n my-shared-storage
oc get pods -o wide -n my-shared-storage

几分钟后，您应该有 4 个文件加载器 Pod。重复上述命令，直到 Running STATUS 中有 4 个 file-uploader Pod。

您可以创建一个 PersistentVolumeClaim，并使用 oc set volume 命令将其附加到应用程序中。执行以下命令 

oc set volume deploy/file-uploader --add --name=my-shared-storage \
-t pvc --claim-mode=ReadWriteMany --claim-size=10Gi \
--claim-name=my-shared-storage --claim-class=ocs-storagecluster-cephfs \
--mount-path=/opt/app-root/src/uploaded \
-n my-shared-storage

此命令将：

  • 创建 PersistentVolumeClaim
  • 更新应用部署，使其包含卷定义
  • 更新应用部署，将卷挂载附加到指定的 mount-path
  • 导致 4 个应用程序 Pod 的新部署

现在，查看添加卷的结果： 

oc get pvc -n my-shared-storage

输出示例： 

NAME                STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS                AGE
my-shared-storage   Bound    pvc-5402cc8a-e874-4d7e-af76-1eb05bd2e7c7   10Gi       RWX            ocs-storagecluster-cephfs   52s

注意 ACCESSMODE 设置为 RWX(ReadWriteMany)。

所有 4 个文件-uploaderPods 都使用相同的 RWX 卷。如果没有此 ACCESSMODE，OpenShift 将不会尝试可靠地将多个 Pod 附加到同一持久性卷。如果您试图扩展正在使用 RWO( ReadWriteOnce)持久性卷的部署，则 Pod 将在同一节点上被在一起。