Nomad Autoscaler

The Nomad Autoscaler is an autoscaling daemon for Nomad, architectured around plug-ins to allow for easy extensibility in terms of supported metrics sources, scaling targets and scaling algorithms.

The Nomad Autoscaler currently supports:

• Horizontal Application Autoscaling: The process of automatically controlling the number of instances of an application to have sufficient work throughput to meet service-level agreements (SLA). In Nomad, horizontal application autoscaling can be achieved by modifying the number of allocations in a task group based on the value of a relevant metric, such as CPU and memory utilization or number of open connections.

• Horizontal Cluster Autoscaling: The process of adding or removing Nomad clients from a cluster to ensure there is an appropriate amount of cluster resource for the scheduled applications. This is achieved by interacting with remote providers to start or terminate new Nomad clients based on metrics such as the remaining free schedulable CPU or memory.

• Dynamic Application Sizing (Enterprise): Dynamic Application Sizing enables organizations to optimize the resource consumption of applications using sizing recommendations from Nomad. It evaluates, processes and stores historical task resource usage data, making recommendations for CPU and Memory resource parameters. The recommendations can be calculated using a number of different algorithms to ensure the recommendation best fits the application profile.

Requirements

The autoscaler relies on Nomad APIs that were introduced in Nomad 0.11-beta1, some of which have been changed during the beta. The compatibility requirements are as follows:

Autoscaler Version	Nomad Version
0.0.1-techpreview1	0.11.0-beta1
0.0.1-techpreview2	0.11.0
0.0.2	0.11.2
0.1.0	0.12.0
0.1.1	0.12.0
0.2.0+	1.0.0+
nightly	1.0.0+

Documentation

Documentation is available on the Nomad project website.

Additional operator guidance for readiness override options is available in docs/readiness-override-options.md.

Demo

There are both horizontal application scaling and dynamic application sizing based demos available providing guided examples of running the autoscaler.

The cloud provider based demo provides guided examples of running horizontal application and cluster scaling.

Building

The Nomad Autoscaler can be easily built for local testing or development using the make dev command. This will output the compiled binary to ./bin/nomad-autoscaler.

Nightly Builds and Docker Image Preview

The Nomad Autoscaler is under constant updates, so every day the nightly release is updated with binaries built off the latest code in the main branch. This should make it easier for you to try new features and bug fixes.

Each commit to main also generates a preview Docker image that can be accessed from the hashicorppreview/nomad-autoscaler repository on Docker Hub.