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Netdata, Prometheus, Grafana stack

Intro

In this article I will walk you through the basics of getting Netdata,
Prometheus and Grafana all working together and monitoring your application
servers. This article will be using docker on your local workstation. We will be
working with docker in an ad-hoc way, launching containers that run ‘/bin/bash’
and attaching a TTY to them. I use docker here in a purely academic fashion and
do not condone running Netdata in a container. I pick this method so individuals
without cloud accounts or access to VMs can try this out and for it’s speed of
deployment.

Why Netdata, Prometheus, and Grafana

Some time ago I was introduced to Netdata by a coworker. We were attempting to
troubleshoot python code which seemed to be bottlenecked. I was instantly
impressed by the amount of metrics Netdata exposes to you. I quickly added
Netdata to my set of go-to tools when troubleshooting systems performance.

Some time ago, even later, I was introduced to Prometheus. Prometheus is a
monitoring application which flips the normal architecture around and polls
rest endpoints for its metrics. This architectural change greatly simplifies
and decreases the time necessary to begin monitoring your applications.
Compared to current monitoring solutions the time spent on designing the
infrastructure is greatly reduced. Running a single Prometheus server per
application becomes feasible with the help of Grafana.

Grafana has been the go to graphing tool for… some time now. It’s awesome,
anyone that has used it knows it’s awesome. We can point Grafana at Prometheus
and use Prometheus as a data source. This allows a pretty simple overall
monitoring architecture: Install Netdata on your application servers, point
Prometheus at Netdata, and then point Grafana at Prometheus.

I’m omitting an important ingredient in this stack in order to keep this tutorial
simple and that is service discovery. My personal preference is to use Consul.
Prometheus can plug into consul and automatically begin to scrape new hosts that
register a Netdata client with Consul.

At the end of this tutorial you will understand how each technology fits
together to create a modern monitoring stack. This stack will offer you
visibility into your application and systems performance.

Getting Started - Netdata

To begin let’s create our container which we will install Netdata on. We need
to run a container, forward the necessary port that netdata listens on, and
attach a tty so we can interact with the bash shell on the container. But
before we do this we want name resolution between the two containers to work.
In order to accomplish this we will create a user-defined network and attach
both containers to this network. The first command we should run is:

docker network create --driver bridge netdata-tutorial

With this user-defined network created we can now launch our container we will
install Netdata on and point it to this network.

docker run -it --name netdata --hostname netdata --network=netdata-tutorial -p 19999:19999  centos:latest '/bin/bash'

This command creates an interactive tty session (-it), gives the container both
a name in relation to the docker daemon and a hostname (this is so you know what
container is which when working in the shells and docker maps hostname
resolution to this container), forwards the local port 19999 to the container’s
port 19999 (-p 19999:19999), sets the command to run (/bin/bash) and then
chooses the base container images (centos:latest). After running this you should
be sitting inside the shell of the container.

After we have entered the shell we can install Netdata. This process could not
be easier. If you take a look at this link, the Netdata devs give us
several one-liners to install netdata. I have not had any issues with these one
liners and their bootstrapping scripts so far (If you guys run into anything do
share). Run the following command in your container.

bash <(curl -Ss https://my-netdata.io/kickstart.sh) --dont-wait

After the install completes you should be able to hit the Netdata dashboard at
http://localhost:19999/ (replace localhost if you’re doing this on a VM or have
the docker container hosted on a machine not on your local system). If this is
your first time using Netdata I suggest you take a look around. The amount of
time I’ve spent digging through /proc and calculating my own metrics has been
greatly reduced by this tool. Take it all in.

Next I want to draw your attention to a particular endpoint. Navigate to
http://localhost:19999/api/v1/allmetrics?format=prometheus&help=yes In your
browser. This is the endpoint which publishes all the metrics in a format which
Prometheus understands. Let’s take a look at one of these metrics.
netdata_system_cpu_percentage_average{chart="system.cpu",family="cpu",dimension="system"}0.0831255 1501271696000 This metric is representing several things which I will
go in more details in the section on prometheus. For now understand that this
metric: netdata_system_cpu_percentage_average has several labels: [chart,
family, dimension]. This corresponds with the first cpu chart you see on the
Netdata dashboard.

This CHART is called ‘system.cpu’, The FAMILY is cpu, and the DIMENSION we are
observing is “system”. You can begin to draw links between the charts in netdata
to the prometheus metrics format in this manner.

Prometheus

We will be installing prometheus in a container for purpose of demonstration.
While prometheus does have an official container I would like to walk through
the install process and setup on a fresh container. This will allow anyone
reading to migrate this tutorial to a VM or Server of any sort.

Let’s start another container in the same fashion as we did the Netdata
container. docker run -it --name prometheus --hostname prometheus--network=netdata-tutorial -p 9090:9090 centos:latest '/bin/bash' This should
drop you into a shell once again. Once there quickly install your favorite
editor as we will be editing files later in this tutorial. yum install vim -y

Prometheus provides a tarball of their latest stable versions here:
https://prometheus.io/download/. Let’s download the latest version and install
into your container.

curl -L 'https://github.com/prometheus/prometheus/releases/download/v1.7.1/prometheus-1.7.1.linux-amd64.tar.gz' -o /tmp/prometheus.tar.gz

mkdir /opt/prometheus

tar -xf /tmp/prometheus.tar.gz -C /opt/prometheus/ --strip-components 1

This should get prometheus installed into the container. Let’s test that we can run
prometheus and connect to it’s web interface. This will look similar to what
follows:

[root@prometheus prometheus]# /opt/prometheus/prometheus
INFO[0000] Starting prometheus (version=1.7.1, branch=master, revision=3afb3fffa3a29c3de865e1172fb740442e9d0133) 
 source="main.go:88"
INFO[0000] Build context (go=go1.8.3, user=root@0aa1b7fc430d, date=20170612-11:44:05)  source="main.go:89"
INFO[0000] Host details (Linux 4.9.36-moby #1 SMP Wed Jul 12 15:29:07 UTC 2017 x86_64 prometheus (none)) source="main.go:90"
INFO[0000] Loading configuration file prometheus.yml source="main.go:252"
INFO[0000] Loading series map and head chunks... source="storage.go:428"
INFO[0000] 0 series loaded. source="storage.go:439"
INFO[0000] Starting target manager... source="targetmanager.go:63"
INFO[0000] Listening on :9090 source="web.go:259"

Now attempt to go to http://localhost:9090/. You should be presented with the
prometheus homepage. This is a good point to talk about Prometheus’s data model
which can be viewed here: https://prometheus.io/docs/concepts/data_model/ As
explained we have two key elements in Prometheus metrics. We have the ‘metric’
and its ‘labels’. Labels allow for granularity between metrics. Let’s use our
previous example to further explain.

netdata_system_cpu_percentage_average{chart="system.cpu",family="cpu",dimension="system"} 0.0831255 1501271696000

Here our metric is
‘netdata_system_cpu_percentage_average’ and our labels are ‘chart’, ‘family’,
and ‘dimension. The last two values constitute the actual metric value for the
metric type (gauge, counter, etc…). We can begin graphing system metrics with
this information, but first we need to hook up Prometheus to poll Netdata stats.

Let’s move our attention to Prometheus’s configuration. Prometheus gets it
config from the file located (in our example) at
/opt/prometheus/prometheus.yml. I won’t spend an extensive amount of time
going over the configuration values documented here:
https://prometheus.io/docs/operating/configuration/. We will be adding a new
“job” under the “scrape_configs”. Let’s make the “scrape_configs” section look
like this (we can use the dns name Netdata due to the custom user-defined
network we created in docker beforehand).

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:9090']

  - job_name: 'netdata'

    metrics_path: /api/v1/allmetrics
    params:
      format: [ prometheus ]

    static_configs:
      - targets: ['netdata:19999']

Let’s start prometheus once again by running /opt/prometheus/prometheus. If we
now navigate to prometheus at ‘http://localhost:9090/targets’ we should see our
target being successfully scraped. If we now go back to the Prometheus’s
homepage and begin to type ‘netdata_’ Prometheus should auto complete metrics
it is now scraping.

Let’s now start exploring how we can graph some metrics. Back in our NetData
container lets get the CPU spinning with a pointless busy loop. On the shell do
the following:

[root@netdata /]# while true; do echo "HOT HOT HOT CPU"; done

Our NetData cpu graph should be showing some activity. Let’s represent this in
Prometheus. In order to do this let’s keep our metrics page open for reference:
http://localhost:19999/api/v1/allmetrics?format=prometheus&help=yes We are
setting out to graph the data in the CPU chart so let’s search for “system.cpu”
in the metrics page above. We come across a section of metrics with the first
comments # COMMENT homogeneus chart "system.cpu", context "system.cpu", family"cpu", units "percentage" Followed by the metrics. This is a good start now let
us drill down to the specific metric we would like to graph.

# COMMENT
netdata_system_cpu_percentage_average: dimension "system", value is percentage, gauge, dt 1501275951 to 1501275951 inclusive
netdata_system_cpu_percentage_average{chart="system.cpu",family="cpu",dimension="system"} 0.0000000 1501275951000

Here we learn that the metric name we care about is
‘netdata_system_cpu_percentage_average’ so throw this into Prometheus and see
what we get. We should see something similar to this (I shut off my busy loop)

This is a good step toward what we want. Also make note that Prometheus will tag
on an ‘instance’ label for us which corresponds to our statically defined job in
the configuration file. This allows us to tailor our queries to specific
instances. Now we need to isolate the dimension we want in our query. To do this
let us refine the query slightly. Let’s query the dimension also. Place this
into our query text box.
netdata_system_cpu_percentage_average{dimension="system"} We now wind up with
the following graph.

Awesome, this is exactly what we wanted. If you haven’t caught on yet we can
emulate entire charts from NetData by using the chart dimension. If you’d like
you can combine the ‘chart’ and ‘instance’ dimension to create per-instance
charts. Let’s give this a try:
netdata_system_cpu_percentage_average{chart="system.cpu", instance="netdata:19999"}

This is the basics of using Prometheus to query NetData. I’d advise everyone at
this point to read this page.
The key point here is that NetData can export metrics from its internal DB or
can send metrics “as-collected” by specifying the ‘source=as-collected’ url
parameter like so.
http://localhost:19999/api/v1/allmetrics?format=prometheus&help=yes&types=yes&source=as-collected
If you choose to use this method you will need to use Prometheus’s set of
functions here: https://prometheus.io/docs/querying/functions/ to obtain useful
metrics as you are now dealing with raw counters from the system. For example
you will have to use the irate() function over a counter to get that metric’s
rate per second. If your graphing needs are met by using the metrics returned by
NetData’s internal database (not specifying any source= url parameter) then use
that. If you find limitations then consider re-writing your queries using the
raw data and using Prometheus functions to get the desired chart.

Grafana

Finally we make it to grafana. This is the easiest part in my opinion. This time
we will actually run the official grafana docker container as all configuration
we need to do is done via the GUI. Let’s run the following command:

docker run -i -p 3000:3000 --network=netdata-tutorial grafana/grafana

This will get grafana running at ‘http://localhost:3000/’ Let’s go there and
login using the credentials Admin:Admin.

The first thing we want to do is click ‘Add data source’. Let’s make it look
like the following screenshot

With this completed let’s graph! Create a new Dashboard by clicking on the top
left Grafana Icon and create a new graph in that dashboard. Fill in the query
like we did above and save.

Conclusion

There you have it, a complete systems monitoring stack which is very easy to
deploy. From here I would begin to understand how Prometheus and a service
discovery mechanism such as Consul can play together nicely. My current prod
deployments automatically register Netdata services into Consul and Prometheus
automatically begins to scrape them. Once achieved you do not have to think
about the monitoring system until Prometheus cannot keep up with your scale.
Once this happens there are options presented in the Prometheus documentation
for solving this. Hope this was helpful, happy monitoring.