Why use a SaaS service?
You may have noticed while working with the examples in the previous chapters that the tools we have used can potentially use many resources if we needed to start collecting more metrics, especially if the applications we want to monitor are in production.
To help shift this load from both storage and CPU, a number of cloud-based SaaS options have started offering support to record metrics for your containers. Many of these services were already offering services to monitor servers, so adding support for containers seemed a natural progression for them.
These typically require you to install an agent on your host machine, once installed, the agent will sit in the background and report to the services, normally cloud-based and API services.
A few of the services allow you to deploy the agents as Docker containers. They offer containerized agents so that the service can run on stripped down operating systems, such as:
CoreOS: https://coreos.com/
RancherOS: http://rancher...
