WalkerNea

Posted on Jun 1

Prometheus Setup Manual

#devops #linux #monitoring #tutorial

This manual explains the basic installation of Prometheus, including how to configure Node Exporter and AlertManager in an easy-to-understand way.

✅ 1. Install Prometheus

🔧 Prepare Users and Directories

sudo su -
yum update -y

# Create the prometheus user (login disabled)
useradd --no-create-home --shell /bin/false prometheus

# Create directories
mkdir /opt/prometheus
mkdir /var/lib/prometheus

# Change ownership to the prometheus user
chown prometheus. /opt/prometheus
chown prometheus. /var/lib/prometheus

📦 Download and Extract the Prometheus Binary

cd /opt/prometheus

# Download the Prometheus binary
curl -LO https://github.com/prometheus/prometheus/releases/download/v2.19.2/prometheus-2.19.2.linux-amd64.tar.gz

# Verify the hash
dwnl=68382959f73354b30479f9cc3e779cf80fd2e93010331652700dcc71f6b05586
diff <(sha256sum prometheus-2.19.2.linux-amd64.tar.gz | awk '{print $1}') <(echo $dwnl)

# Extract the archive
tar -zxvf prometheus-2.19.2.linux-amd64.tar.gz
cd prometheus-2.19.2.linux-amd64

# Copy binaries
cp -v prometheus /usr/local/bin/
cp -v promtool /usr/local/bin/
chown prometheus. /usr/local/bin/prometheus
chown prometheus. /usr/local/bin/promtool

✅ 2. Install Node Exporter

curl -LO https://github.com/prometheus/node_exporter/releases/download/v1.0.1/node_exporter-1.0.1.linux-amd64.tar.gz
chown ec2-user. node_exporter-1.0.1.linux-amd64.tar.gz
tar -zxvf node_exporter-1.0.1.linux-amd64.tar.gz

✅ 3. Create the Prometheus systemd Service

cat << _EOF_ > /usr/lib/systemd/system/prometheus.service
[Unit]
Description=Prometheus Service
After=network.target

[Service]
Type=simple
Restart=always
RestartSec=1
User=prometheus
Group=prometheus
ExecStart=/usr/local/bin/prometheus \
  --web.enable-lifecycle \
  --config.file=/opt/prometheus/prometheus-2.19.2.linux-amd64/prometheus.yml \
  --storage.tsdb.path=/var/lib/prometheus \
  --web.console.templates=/opt/prometheus/prometheus-2.19.2.linux-amd64/consoles \
  --web.console.libraries=/opt/prometheus/prometheus-2.19.2.linux-amd64/console_libraries \
  --storage.tsdb.retention=8d

[Install]
WantedBy=multi-user.target
_EOF_

# Start and enable the service
systemctl daemon-reload
systemctl start prometheus
systemctl enable prometheus

📌 If you want to reload Prometheus via API:

curl -X POST http://<PROMETHEUS_IP>:9090/-/reload

✅ 4. Create the Node Exporter Service

cat << _EOF_ > /usr/lib/systemd/system/node-exporter.service
[Unit]
Description=Node Exporter Service
After=network.target

[Service]
Type=simple
Restart=always
RestartSec=1
User=prometheus
Group=prometheus
ExecStart=/home/ec2-user/node_exporter-1.0.1.linux-amd64/node_exporter
ExecReload=/bin/kill -s HUP $MAINPID
ExecStop=/bin/kill -s QUIT $MAINPID

[Install]
WantedBy=multi-user.target
_EOF_

systemctl daemon-reload
systemctl start node-exporter
systemctl enable node-exporter

✅ 5. Access Prometheus

Open the following URL in your browser to check the metrics:

http://<PROMETHEUS_IP>:9090/metrics

✅ 6. Example prometheus.yml Configuration File

global:
  scrape_interval: 15s
  evaluation_interval: 15s

alerting:
  alertmanagers:
    - static_configs:
        - targets: ['localhost:9093']

rule_files:
  - rules.yml

scrape_configs:
  - job_name: 'prometheus'
    static_configs:
      - targets: ['localhost:9090']

✅ 7. Install and Configure AlertManager

curl -LO https://github.com/prometheus/alertmanager/releases/download/v0.21.0/alertmanager-0.21.0.linux-amd64.tar.gz
dwnl=9ccd863937436fd6bfe650e22521a7f2e6a727540988eef515dde208f9aef232
diff <(sha256sum alertmanager-0.21.0.linux-amd64.tar.gz | awk '{print $1}') <(echo $dwnl)
tar -zxvf alertmanager-0.21.0.linux-amd64.tar.gz

cp -v alertmanager-0.21.0.linux-amd64/alertmanager /usr/local/bin/
cp -v alertmanager-0.21.0.linux-amd64/amtool /usr/local/bin/

Create the AlertManager systemd Service

cat << _EOF_ > /usr/lib/systemd/system/alert-manager.service
[Unit]
Description=AlertManager Service for Prometheus
After=network.target

[Service]
Type=simple
Restart=always
RestartSec=1
User=prometheus
Group=prometheus
ExecStart=/usr/local/bin/alertmanager --config.file=/home/ec2-user/alertmanager-0.21.0.linux-amd64/alertmanager.yml

[Install]
WantedBy=multi-user.target
_EOF_

systemctl daemon-reload
systemctl start alert-manager
systemctl enable alert-manager

✅ 8. Example Rule File (rules.yml)

groups:
  - name: example
    rules:
      - alert: InstanceDown
        expr: up == 0
        for: 1m

🔗 Reference Links

Prometheus Official Website: https://prometheus.io
GitHub: https://github.com/prometheus
GitLab Integration: https://docs.gitlab.com/ee/administration/monitoring/prometheus/
AlertManager Templates: https://www.freedesktop.org/software/systemd/man/systemd.service.html

If you would like further improvements to this manual, Kubernetes integration, or Slack notification setup examples, feel free to ask!

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