An image contains the code used to create a deployment. Then, a deployment can be created from an image, which should then create a replica set (which is the number of pods that should be created), and then the pods should be created.

There are various ways to deploy an app.

• From GitHub (https://github.com)
• From Docker Hub (https://hub.docker.com)
• From an image
• From a build
• From a template
• From a JSON or YAML file (templates)

Before importing an image, the oc get images command can be used to determine if the image has already been imported.

~]# oc get images
NAME                                                                      IAMGE REFERENCE
sha256:0089883f8e4387618946cd24378a447b8cf7e5dfaa146b94acab27fc5e170a14   registry.example.com/jboss-webserver-3/webserver30-tomcat8-openshift@sha256:0089883f8e4387618946cd24378a447b8cf7e5dfaa146b94acab27fc5e170a14
sha256:0155e28b6b10d6fba7144df9ce33105acbab32766836baacc67c76b900a58772   registry.example.com/redhat-sso-7/sso70-openshift@sha256:0155e28b6b10d6fba7144df9ce33105acbab32766836baacc67c76b900a58772
sha256:03416282b034b93614ab2af74441ce481226bcf0b0b6c614cacd1b6f008f9792   registry.example.com/jboss-eap-6/eap64-openshift@sha256:03416282b034b93614ab2af74441ce481226bcf0b0b6c614cacd1b6f008f9792
sha256:03795eb1e54f94ffb822b8b3997b5f5bbeaa20bdf7006841864738d1eb58054b   registry.example.com/rhpam-7/rhpam72-businesscentral-openshift@sha256:03795eb1e54f94ffb822b8b3997b5f5bbeaa20bdf7006841864738d1eb58054b

The oc new-build command can be used to import an image from an external registry, such as GitHub. In this example, an image named camel-app is imported.

~]$ oc new-build fabric8/s2i-java~https://github.com/monodot/simple-camel-spring-boot-app --name=camel-app
--> Found container image ec41b73 (20 months old) from Docker Hub for "fabric8/s2i-java"

    Java Applications 
    ----------------- 
    Platform for building and running plain Java applications (fat-jar and flat classpath)

    Tags: builder, java

    * An image stream tag will be created as "s2i-java:latest" that will track the source image
    * A source build using source code from https://github.com/monodot/simple-camel-spring-boot-app will be created
      * The resulting image will be pushed to image stream tag "my-demo-app:latest"
      * Every time "s2i-java:latest" changes a new build will be triggered

--> Creating resources with label build=camel-app ...
    imagestream.image.openshift.io "s2i-java" created
    imagestream.image.openshift.io "camel-app" created
    buildconfig.build.openshift.io "camel-app" created
--> Success

The oc get builds command can then be used to determine if the build is running.

~]$ oc get builds
NAME               TYPE     FROM   STATUS                       STARTED         DURATION
camel-app-1        Source   Git    Running                      2 minutes ago

And the oc get imagestreams command should return something like this.

~]$ oc get is | grep -i demo
camel-app                                    image-registry.openshift-image-registry.svc:5000/foo/camel-app