Kubernetes Jenkins Plugin Creating more resources for pending slaves
Since you're using Google Cloud, you can edit your existing node pool to enable autoscaling:
GKE's cluster autoscaler automatically resizes clusters based on the demands of the workloads you want to run. With autoscaling enabled, GKE automatically adds a new node to your cluster if you've created new Pods that don't have enough capacity to run; conversely, if a node in your cluster is underutilized and its Pods can be run on other nodes, GKE can delete the node.
This means that when you need, you'll have more nodes added to your node pool to met the resource demand for your workload.
Alternatively and if you have enough room in your node, you can increase the number of pods using Horizontal Pod Autoscaling:
Horizontal Pod Autoscaler automatically scales the number of pods in a replication controller, deployment or replica set based on observed CPU utilization
This will create more pods instead of nodes, based on the pod resource usage metrics.