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Language:
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Language:
English
Chapter 2. Using .NET Core 3.0 on Red Hat OpenShift Container Platform
2.1. Installing Image Streams
The .NET Core image streams definition can be defined globally in the openshift namespace or locally in your specific project.
If you are a system administrator or otherwise have sufficient permissions, change to the
openshiftproject. Using theopenshiftproject allows you to globally update the image stream definitions.$ oc project openshift
If you do not have permissions to use the
openshiftproject, you can still update your project definitions starting with Step 2.Run the following commands to list all available .NET Core image versions.
$ oc describe is dotnet -n openshift $ oc describe is dotnet
The output shows installed images or the message
Error from server (NotFound)if no images are installed.Enter the following command to import new image streams.
$ oc create -f https://raw.githubusercontent.com/redhat-developer/s2i-dotnetcore/master/dotnet_imagestreams_rhel8.json
If image streams were already installed, use the
replacecommand to update the image stream definitions.$ oc replace -f https://raw.githubusercontent.com/redhat-developer/s2i-dotnetcore/master/dotnet_imagestreams_rhel8.json
2.2. Deploying Applications from Source
Run the following commands to deploy the ASP.NET Core application, which is in the
appfolder on thedotnetcore-3.0branch of theredhat-developer/s2i-dotnetcore-exGitHub repository.$ oc new-app --name=exampleapp 'dotnet:3.0~https://github.com/redhat-developer/s2i-dotnetcore-ex#dotnetcore-3.0' --build-env DOTNET_STARTUP_PROJECT=app
Use the
oc logscommand to track progress of the build.$ oc logs -f bc/exampleapp
View the deployed application once the build is finished.
$ oc logs -f dc/exampleapp
At this point, the application is accessible within the project. To make it accessible externally, use the
oc exposecommand. You can then useoc get routesto find the URL.$ oc expose svc/exampleapp $ oc get routes
2.3. Deploying Applications from Binary Artifacts
The .NET Core S2I builder image can be used to build an application using binary artifacts that you provide.
Publish your application as described in Publish Applications. For example, the following commands create a new web application and publish it.
$ dotnet new web -o webapp $ cd webapp $ dotnet publish -c Release
Create a new binary build using the
oc new-buildcommand.$ oc new-build --name=mywebapp dotnet:3.0 --binary=true
Start a build using the
oc start-buildcommand, specifying the path to the binary artifacts on your local machine.$ oc start-build mywebapp --from-dir=bin/Release/netcoreapp3.0/publish
Create a new application using the
oc new-appcommand.$ oc new-app mywebapp
2.4. Environment Variables
The .NET Core images support a number of environment variables to control the build behavior of your .NET Core application. These variables can be set as part of the build configuration, or they can be added to an .s2i/environment file in the application source code repository.
| Variable Name | Description | Default |
|---|---|---|
| DOTNET_STARTUP_PROJECT |
Selects project to run. This must be a project file (for example, |
|
| DOTNET_ASSEMBLY_NAME |
Selects the assembly to run. This must not include the .dll extension. Set this to the output assembly name specified in |
The name of the |
| DOTNET_PUBLISH_READRYTORUN |
When set to |
|
| DOTNET_RESTORE_SOURCES |
Specifies the space-separated list of NuGet package sources used during the restore operation. This overrides all of the sources specified in the | |
| DOTNET_RESTORE_CONFIGFILE |
Specifies a | |
| DOTNET_TOOLS |
Specifies a list of .NET tools to install before building the app. It is possible to install a specific version by post pending the package name with | |
| DOTNET_NPM_TOOLS | Specifies a list of NPM packages to install before building the application. | |
| DOTNET_TEST_PROJECTS |
Specifies the list of test projects to test. This must be project files or folders containing a single project file. | |
| DOTNET_CONFIGURATION |
Runs the application in Debug or Release mode. This value should be either |
|
| DOTNET_VERBOSITY |
Specifies the verbosity of the | |
| HTTP_PROXY, HTTPS_PROXY | Configures the HTTP/HTTPS proxy used when building and running the application. | |
| DOTNET_RM_SRC |
When set to | |
| DOTNET_SSL_DIRS |
Used to specify a list of folders/files with additional SSL certificates to trust. The certificates are trusted by each process that runs during the build and all processes that run in the image after the build (including the application that was built). The items can be absolute paths (starting with | |
| NPM_MIRROR | Uses a custom NPM registry mirror to download packages during the build process. | |
| ASPNETCORE_URLS |
This variable is set to | |
| DOTNET_RESTORE_DISABLE_PARALLEL | When set to true, disables restoring multiple projects in parallel. This reduces restore timeout errors when the build container is running with low CPU limits. |
|
| DOTNET_INCREMENTAL | When set to true, the NuGet packages will be kept so they can be re-used for an incremental build. |
|
| DOTNET_PACK |
When set to true, creates a | |
| DOTNET_STARTUP_ASSEMBLY | Used to specify the path of the entrypoint assembly within the source repository. When set, the source repository must contain a pre-built application. |
2.5. Sample Applications
Three sample applications are available:
- dotnet-example: This is the default model–view–controller (MVC) application.
-
dotnet-runtime-example: This shows how to build an MVC application using a chained build. The application is built in
ubi8/dotnet-30. The result is deployed inubi8/dotnet-30-runtime. Note that chained builds are not supported on OpenShift Online. dotnet-pgsql-persistent: This is the Microsoft ASP.NET Core MusicStore sample application using a PostgreSQL backend.
NoteThis application uses .NET Core 2.1 LTS.
To add the samples using the OpenShift Web Console, browse to your project and click Add to project. You can filter for dotnet. If the samples do not show up, you can add them to your installation by running the following commands.
$ oc create -f https://raw.githubusercontent.com/redhat-developer/s2i-dotnetcore/master/templates/dotnet-example.json $ oc create -f https://raw.githubusercontent.com/redhat-developer/s2i-dotnetcore/master/templates/dotnet-runtime-example.json $ oc create -f https://raw.githubusercontent.com/redhat-developer/s2i-dotnetcore/master/templates/dotnet-pgsql-persistent.json