Reduce overhead of cronjobs

We have a cluster that experiences high load every 3 minutes. It's highly likely that this happens because several websites have their cronjob on the same schedule.

We are not certain if the cronjobs themselves are the problem, or if the high load is also caused by the overhead Kubernetes adds when running cronjobs in this way (every 3 minutes Kubernetes needs to schedule a new pod for the job, run the job, then garbage collect the pod).

In other words, Kubernetes CronJob might be overkill for the simple curl request we want to run every 3 minutes. If this is true, the best mitigation for our current problem is to build the curl call into the wordpress pod as a third container, much like the backup calls. That reduces the overhead of the crons, I hope so much that the stress on the cluster will also be lower