Env variables:
PORT = "80": Port on which the application is going to be listening.NOMAD_HOST = "http://nomad.service.consul:4646": Nomad host endpoint.NOMAD_REGION = "global": Nomad Region.VAULT_TOKEN = "ljkasdflkjafd": Token for vault with permission to access every secret needed for all the scale jobs.USE_SLACK = "true": Flag to enable the use of slack as a system message application.HTTP_USER = "user": User needed for basic auth for endpoints to scale up or down manually.HTTP_PASS = "password": Password needed for basic auth for endpoints to scale up or down manuallyMETRICS_ENDPOINT = "http://prometheus.yourorg.com/api/v1/query?query=": Endpoint from where to get the metrics which are going to be used to triger the scale events.
Inside Job file (At taskGroup lvl):
meta {
scaler = "true" Activate the scaler
min_query = "sum(rate(nomad_client_allocs_cpu_total_ticks{exported_job='scaler-test'}[1m]))by(exported_job) < bool 1" Query that gives the Min threshold for scaling down
max_query = "sum(rate(nomad_client_allocs_cpu_total_ticks{exported_job='scaler-test'}[1m]))by(exported_job) > bool 2" Query that gives the Max threshold for scaling up
query_fire_time = "2m" Time the query need to be true before triggering the saling event
scale_cooldown_down = "20s" Time in cooldown for a scale dow event
scale_cooldown_up = "25s" Time in cooldown for a scale up event
scale_count_down = "1" Amount of containers that are going to be removed on a scale down event
scale_count_up = "2" Amount of containers that are going to be added on a scale up event
scale_max = "16" Maximun amount of containers
scale_min = "1" Minimun amount amount of containers
}