Alertmanager Installation Systemd

This guide explains how to set up Alertmanager to be managed by systemd. The instructions are similar to the setups for Prometheus and Node Exporter. Follow the steps below to download Alertmanager, configure the necessary files and permissions, and finally run Alertmanager as a systemd service.

Step 1: Download and Extract Alertmanager

Download the Alertmanager package, extract its contents, and switch to the extracted directory:

wget https://github.com/prometheus/alertmanager/releases/download/v0.24.0/alertmanager-0.24.0.linux-amd64.tar.gz
# Note: You might encounter an SSL certificate issue:
tar xzf alertmanager-0.24.0.linux-amd64.tar.gz
cd alertmanager-0.24.0.linux-amd64

Step 2: Create the Alertmanager User

Create a dedicated user named alertmanager to run the application. This user does not require a home directory and should have a disabled login shell:

sudo useradd --no-create-home --shell /bin/false alertmanager

Step 3: Configure Alertmanager Files

Set up the configuration and data directories for Alertmanager, then change ownership to the new user.

1. Create the configuration directory, move the configuration file, and update its permissions:

   sudo mkdir /etc/alertmanager
   sudo mv alertmanager.yml /etc/alertmanager
   sudo chown -R alertmanager:alertmanager /etc/alertmanager
   

2. Create the data directory for runtime data storage and update its ownership:

   sudo mkdir /var/lib/alertmanager
   sudo chown -R alertmanager:alertmanager /var/lib/alertmanager
   

Step 4: Install the Executables

Copy the Alertmanager executable into /usr/local/bin so it is available system-wide:

sudo cp alertmanager /usr/local/bin

After copying, update the ownership of the executable:

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

If you choose to manage amtool similarly, adjust its ownership likewise:

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

Step 5: Create the Systemd Service File

Create and configure a new systemd service file for Alertmanager:

1. Open a new service file for editing:

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

2. Insert the following content into the file:

   [Unit]
   Description=Alert Manager
   Wants=network-online.target
   After=network-online.target
   
   [Service]
   Type=simple
   User=alertmanager
   Group=alertmanager
   ExecStart=/usr/local/bin/alertmanager \
     --config.file=/etc/alertmanager/alertmanager.yml \
     --storage.path=/var/lib/alertmanager
   Restart=always
   
   [Install]
   WantedBy=multi-user.target
   

Ensure the ExecStart command correctly points to the configuration file and data storage directory.

Step 6: Reload systemd and Start Alertmanager

After setting up the service file, reload systemd to register the new service, then start and enable Alertmanager:

sudo systemctl daemon-reload
sudo systemctl start alertmanager
sudo systemctl enable alertmanager

Verification and Troubleshooting

Verify the extracted Alertmanager directory's contents to ensure all necessary files are present:

ls -la
total 55752
drwxr-xr-x 2 user1 user1  4096 Mar 25  2022 .
drwxr-xr-x 19 user1 user1  4096 Nov 14 15:34 ..
-rwxr-xr-x 1 user1 user1 31988661 Mar 25  2022 alertmanager
-rw-r--r-- 1 user1 user1    356 Mar 25  2022 alertmanager.yml
-rw-r--r-- 1 user1 user1  11357 Mar 25  2022 amtool
-rw-r--r-- 1 user1 user1    457 Mar 25  2022 LICENSE
-rw-r--r-- 1 user1 user1    197 Mar 25  2022 NOTICE

If you receive an error while setting ownership (e.g., chown: invalid user: 'alertmanager:alertmanager'), ensure the user was created correctly. Then repeat the command:

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

Repeat ownership changes for amtool if necessary:

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

Finally, reload systemd and re-start the service:

sudo systemctl daemon-reload
sudo systemctl start alertmanager
sudo systemctl enable alertmanager

At this point, Alertmanager has been successfully installed and managed by systemd. For additional details on configuring and using Alertmanager, consult the Alertmanager Documentation.