Installing Prometheus Alertmanager

Prometheus alerts allow you to issue automated notifications when certain events occur, triggered by your metric data. Alertmanager is a necessary component in this process, handling the process of sending alerts to the appropriate destination, as well as adding some additional control over alerting functionality. In this lab, you will have the opportunity to install and configure an Alertmanager instance, and connect it to an existing Prometheus server.

Learning Objectives

Successfully complete this lab by achieving the following learning objectives:

Install Alertmanager

Create a user and group for Alertmanager:

sudo useradd -M -r -s /bin/false alertmanager

Download and install the Alertmanager binaries:

wget https://github.com/prometheus/alertmanager/releases/download/v0.20.0/alertmanager-0.20.0.linux-amd64.tar.gz

tar xvfz alertmanager-0.20.0.linux-amd64.tar.gz

sudo cp alertmanager-0.20.0.linux-amd64/alertmanager /usr/local/bin/

sudo chown alertmanager:alertmanager /usr/local/bin/alertmanager

sudo mkdir -p /etc/alertmanager

sudo cp alertmanager-0.20.0.linux-amd64/alertmanager.yml /etc/alertmanager

sudo chown -R alertmanager:alertmanager /etc/alertmanager

sudo mkdir -p /var/lib/alertmanager

sudo chown alertmanager:alertmanager /var/lib/alertmanager

Create a systemd unit for Alertmanager:

sudo vi /etc/systemd/system/alertmanager.service

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

[Service]
User=alertmanager
Group=alertmanager
Type=simple
ExecStart=/usr/local/bin/alertmanager 
  --config.file /etc/alertmanager/alertmanager.yml 
  --storage.path /var/lib/alertmanager/

[Install]
WantedBy=multi-user.target

Start and enable the alertmanager service:

sudo systemctl enable alertmanager

sudo systemctl start alertmanager

Verify the service is running and you can reach it:

sudo systemctl status alertmanager

curl localhost:9093

You can also access Alertmanager in a web browser at http://<PROMETHEUS_SERVER_PUBLIC_IP>:9093.

Install `amtool`

Install the amtool binary:

sudo cp alertmanager-0.20.0.linux-amd64/amtool /usr/local/bin/

Create a config file for amtool:

sudo mkdir -p /etc/amtool

sudo vi /etc/amtool/config.yml

Enter the following content in the config file:
```
alertmanager.url: http://localhost:9093
```
Verify amtool is working by pulling the current Alertmanager configuration:
```
amtool config show
```

Configure Prometheus to Use Alertmanager

Edit the Prometheus config:
```
sudo vi /etc/prometheus/prometheus.yml
```

Under alerting, add your Alertmanager as a target:

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

Restart Prometheus to reload the configuration:
```
sudo systemctl restart prometheus
```
Verify Prometheus is able to reach the Alertmanager. Access the Prometheus Expression Browser in a web browser at http://<PROMETHEUS_SERVER_PUBLIC_IP>:9090/graph. Run the following query and ensure the current value is 1:
```
prometheus_notifications_alertmanagers_discovered
```

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Installing Prometheus Alertmanager

About this Hands-on Lab

Learning Objectives

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