Tag: linux

Prometheus is used an open source software, that can collect metrics and alerting.

You can download latest version oof Prometheus from

https://prometheus.io/download/

Create a user

useradd --no-create-home --system --shell /bin/false prometheus

Download and Install prometheus

cd /usr/local/src
wget https://github.com/prometheus/prometheus/releases/download/v2.31.0-rc.1/prometheus-2.31.0-rc.1.linux-amd64.tar.gz
tar xvf prometheus-2.31.0-rc.1.linux-amd64.tar.gz
cd prometheus-2.31.0-rc.1.linux-amd64
mv prometheus /usr/local/bin/
mv promtool /usr/local/bin/
mkdir /etc/prometheus
mkdir /var/lib/prometheus
mv consoles /etc/prometheus
mv console_libraries /etc/prometheus
mv prometheus.yml /etc/prometheus
chown prometheus:prometheus /etc/prometheus
chown prometheus:prometheus /var/lib/prometheus

Create a service file

vi /etc/systemd/system/prometheus.service

Add following content

[Unit]
Description=Prometheus
Wants=network-online.target
After=network-online.target

[Service]
User=prometheus
Group=prometheus
Type=simple
ExecStart=/usr/local/bin/prometheus \
    --config.file /etc/prometheus/prometheus.yml \
    --storage.tsdb.path /var/lib/prometheus/ \
    --web.console.templates=/etc/prometheus/consoles \
    --web.console.libraries=/etc/prometheus/console_libraries

[Install]
WantedBy=multi-user.target

Enable prometheus to start on boot

systemctl enable prometheus

Start prometheus

systemctl start prometheus
systemctl status prometheus

Prometheus runs on port 9090, you can access promethus at

http://YOUR_SERVER_IP:9090/graph

It will look like

Prometheus have some basic graphing features, but you can’t use it for monitoring. To create dash board and monitor, you need to use grafana.

Collecting Data

Node Exporter is used to collect data from servers. All monitored servers need Node Exporter installed. You can download latest version of NodeExporter from

https://github.com/prometheus/node_exporter/releases

Lets create a user for Node Exporter to run

useradd --no-create-home --system --shell /bin/false node_exporter

Install Node Exporter

cd /usr/local/src
wget https://github.com/prometheus/node_exporter/releases/download/v1.2.2/node_exporter-1.2.2.linux-amd64.tar.gz
tar xvf node_exporter-1.2.2.linux-amd64.tar.gz
cd /usr/local/src/node_exporter-1.2.2.linux-amd64/
mv node_exporter /usr/local/bin/

Create a systemd service file for node exporter

vi /etc/systemd/system/node_exporter.service

Add

[Unit]
Description=Node Exporter
Wants=network-online.target
After=network-online.target

[Service]
User=node_exporter
Group=node_exporter
Type=simple
ExecStart=/usr/local/bin/node_exporter

[Install]
WantedBy=multi-user.target

Enable and start Node Exporter

systemctl enable node_exporter
systemctl start node_exporter
systemctl status node_exporter

Node Exporter run on port 9100 and expose system metrics on url

http://SERVER_IP:9100/metrics

Adding Servers to Prometheus

Once Node Exporter installed on a server, you need to tell Prometheus to get data from the Node Exporter you just installed. To do this, edit Prometheus configuration file.

vi /etc/prometheus/prometheus.yml

Add following

  - job_name: 'node_exporter'
    scrape_interval: 5s
    static_configs:
      - targets: ['SERVER_IP:9100']

To monitor multiple servers, you can dd more servers in targets line. Here is an example config

https://gist.github.com/serverok/83a622e7577da36384f87fe60c9930af/raw

Restart prometheus

systemctl restart prometheus

Grafana

Grafana is used to visualise data collected by Prometheus. You can download Grafana from

https://grafana.com/grafana/download

Grafana offers free cloud hosted version with some limitation (1 user, 5 dashboards). Free version is suitable if you are getting started and don’t want to install your own. You can signup for cloud hosted version at

https://grafana.com/get

If you decide to install your own Grafana, you can run

cd /usr/local/src
wget https://dl.grafana.com/oss/release/grafana_7.3.7_amd64.deb
dpkg -i grafana_7.3.7_amd64.deb

Enable and start grafana

systemctl enable grafana-server
systemctl start grafana-server
systemctl status grafana-server

If you did your own install, grafana runs on port 3000. To access, use url

http://SERVER_IP:3000/login

Default username and passwords are “admin”. Once logged in you will be asked to set password for grafana admin user.

Before you can use Grafana, you need to set a data source and create dash board. In our case, data source is prometheus. To connect Grafana to your Prometheus insallation, go to Settings > Data Sources

On next page, select Prometheus

On next page, for URL, enter http://PROMETHUS_SERVER_IP:9090, scroll down, click on “Save & Test” button. If grafana can connect to your prometheus installation, you should see success message with “Data source is working”. If not, you need to check your firewall rules.

Creating Grafana Dashboards

Grafana displays data in dash boards. You can create your own or use pre existing dash boards. You can find pre-made dash boards at

https://grafana.com/grafana/dashboards

On my grafana installation, i used dashboard

https://grafana.com/grafana/dashboards/11074

To add this dash board to your Grafana, click on the + button, then select Import. On next screen, you can enter ID for the dash board you need to import. In this case 11074. Click “Load” button to import the dash board.

Here is a dash board for one of the server

You can edit Panels in grafana dash board to see how it is created. You can create a new dash board with panel you need. This way your dashboards only show required information.

Related Posts

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Prometheus Node Exporter on non default port
Prometheus init script for CentOS 6