OneUptime (https://github.com/oneuptime/oneuptime) is the open-source alternative to StausPage.io + UptimeRobot + PagerDuty. We're working on adding APM functionalities to it to make it closer to an open-source alternative to data dog. It's 100% free and you can self-host it on your VM / server.
UPDATE: Docker Compose file is in the repo and Its now on ArtifactHub: https://artifacthub.io/packages/helm/oneuptime/oneuptime and you can try it out on your K8s clusters.
Looking forward to hearing what you all think!
It'll be the same. We recommend 16gb of RAM and that's an overkill. This can comfortably run in 4 GB.