<p>I use the Jenkins kubernetes plugin to build a job, but when I start build I have to wait for about 15s before the slave is online.  Why does this happen?</p>

<p>You need to be aware that when you use the Kubernetes Plugin, your Jenkins-slave is created on demand when you build a job. Supposing you are using the jnlp-slave as your jenkins-slave image, 15s is the time need for k8s to schedule the pod and to start up the jnlp slave jar.</p>

<p>What you can do in order to optimize the time, is using the option <code>Time in minutes to retain slave when idle</code> in the Kubernetes Plugin configuration, that holds the pods running for a determined amount of time, so the next builds can reuse that slave.</p>
