Deploy Prometheus to Cloud Foundry - go

Question

I want to deploy Prometheus to Cloud Foundry without using Docker container. When I try to deploy it with the standard Cloud Foundry Go Buildpack I get the following error:
can't load package: package prometheus: no buildable Go source files in /tmp/tmp.vv4iyDzMvE/.go/src/prometheus
Which somehow makes sense, because there are actually no sources in the root directory and the project is compiled with the Prometheus utility tool.
Is there any way to deploy Prometheus to Cloud Foundry, like using another Buildpack or something?

Answer 1

I had the same question, but (just today) came up with a slightly different solution, that seemed easier to me.
I used the prometheus-2.2.1-linux-amd64 binary build.
I modified the prometheus.yml to use the default port 8080 as a target (last line):
# my global config
global:
scrape_interval: 15s # Set the scrape interval to every 15 seconds. Default is every 1 minute.
evaluation_interval: 15s # Evaluate rules every 15 seconds. The default is every 1 minute.
# scrape_timeout is set to the global default (10s).
# Alertmanager configuration
alerting:
alertmanagers:
- static_configs:
- targets:
# - alertmanager:9093
# Load rules once and periodically evaluate them according to the global 'evaluation_interval'.
rule_files:
# - "first_rules.yml"
# - "second_rules.yml"
# A scrape configuration containing exactly one endpoint to scrape:
# Here it's Prometheus itself.
scrape_configs:
# The job name is added as a label `job=<job_name>` to any timeseries scraped from this config.
- job_name: 'prometheus'
# metrics_path defaults to '/metrics'
# scheme defaults to 'http'.
static_configs:
- targets: ['localhost:8080'] ###### Only changed this line
Then I added a manifest.yml
---
applications:
- name: prometheus
instances: 1
buildpack: https://github.com/cloudfoundry/binary-buildpack.git
command: ./prometheus --config.file=prometheus.yml --web.listen-address=:8080 --web.enable-admin-api
memory: 1024M
random-route: true
That is using the binary-buildpack, and tells prometheus to startup the server listening on port 8080.
2 files changes and this:
cf push
Now I have prometheus running in my space on Pivotal Web Services.

Answer 2

Prometheus is a TSDB. And it is intended to consume gigabytes and gigabytes of data.
On a Cloud Foundry platform, you are limited by available resources.
So, why deploy Prometheus to Cloud Foundry?
Why not spin up a standalone bosh director and deploy Prometheus through the director as a Bosh deployment, and a standalone. Then inject it as a CUPS into Cloud Foundry?
I am just curious and trying to understand the use case.

Answer 3

Ok, after digging around a bit I got the whole thing working as follows
manifest.yml
---
applications:
- name: prometheus
instances: 1
buildpack: https://github.com/cloudfoundry/go-buildpack.git
command: prometheus
env:
GOPACKAGENAME: github.com/prometheus/prometheus
GO_INSTALL_PACKAGE_SPEC: github.com/prometheus/prometheus/cmd/prometheus
memory: 1000M
BUT in order to listen on the right port, the only solution I could find is adding the following to the cmd/prometheus/config.go file to the beginning of the init() function
port := ":9090"
if s := os.Getenv("PORT"); s != "" {
port = ":"+s
}
and then changing the following part (also in the init() function)
cfg.fs.StringVar(
&cfg.web.ListenAddress, "web.listen-address", ":9090",
"Address to listen on for the web interface, API, and telemetry.",
)
to
cfg.fs.StringVar(
&cfg.web.ListenAddress, "web.listen-address", port,
"Address to listen on for the web interface, API, and telemetry.",
)
After that you can simply deploy the application with cf push and everything should work as a charm