<p>is there a set of commands to change the docker image name/tag in an existing deployment in a project in an OpenShift cluster?</p>

DlekaShelHaHaim
<p>You can use the <code>oc set image</code> command to change the image for a container in an existing Deployment / DeploymentConfig:</p>
<pre><code>oc set image dc/myapp mycontainer=nginx:1.9.1
</code></pre>
<p>Try <code>oc set image --help</code> for some examples.</p>
