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🚀 Installing and Running Loki (Grafana) on Linux 🖥️

Loki is a log aggregation system by Grafana, designed to store and query logs efficiently. Follow the steps below to download, install, and run Loki on your Linux system.

👥 Step 1: Download Loki Binary​

curl -O -L "https://github.com/grafana/loki/releases/download/v3.4.2/loki-linux-amd64.zip"

👉 This command does the following:

  • -O → Saves the file with the same name as in the URL.
  • -L → Follows redirects (useful if the URL redirects to another location).
  • Downloads Loki v3.4.2 for Linux AMD64 architecture.

📂 Step 2: Extract the Loki Binary​

unzip loki-linux-amd64.zip
sudo mv loki-linux-amd64 /usr/bin/loki

👉 This extracts the loki-linux-amd64 binary from the ZIP file.

If unzip is not installed, install it using:

  • Debian/Ubuntu: sudo apt install unzip
  • CentOS/RHEL: sudo yum install unzip
  • Arch Linux: sudo pacman -S unzip

📝 Step 3: Download Loki Configuration File​

sudo mkdir -p /etc/loki
wget https://raw.githubusercontent.com/grafana/loki/v3.4.2/cmd/loki/loki-local-config.yaml -O /etc/loki/config.yaml

👉 This downloads the default Loki configuration file (loki-local-config.yaml) from the Grafana Loki GitHub repository.

🔹 Why do we need this?

  • It provides the basic settings required for running Loki.
  • You can modify it later based on your requirements.

Example config to auto-delete logs after 24 hours:​

auth_enabled: false

server:
  http_listen_port: 3100
  grpc_listen_port: 9096
  log_level: debug
  grpc_server_max_concurrent_streams: 1000

common:
  instance_addr: 127.0.0.1
  path_prefix: /tmp/loki
  storage:
    filesystem:
      chunks_directory: /tmp/loki/chunks
      rules_directory: /tmp/loki/rules
  replication_factor: 1
  ring:
    kvstore:
      store: inmemory

schema_config:
  configs:
    - from: 2025-04-08
      store: tsdb
      object_store: filesystem
      schema: v13
      index:
        prefix: index_
        period: 24h

compactor:
  working_directory: /tmp/loki/compactor
  compaction_interval: 10m
  retention_enabled: true
  retention_delete_delay: 2h
  retention_delete_worker_count: 150
  delete_request_store: filesystem

limits_config:
  retention_period: 24h

ruler:
  alertmanager_url: http://localhost:9093

frontend:
  encoding: protobuf

# Uncomment to disable reporting:
# analytics:
#   reporting_enabled: false

🚀 Step 4: Create a Systemd Service for Loki​

Create a systemd service file for Loki at /etc/systemd/system/loki.service:

sudo tee /etc/systemd/system/loki.service > /dev/null <<EOF
[Unit]
Description=Loki Log Aggregation System
After=network.target

[Service]
User=root
Group=root
ExecStart=/usr/bin/loki -config.file /etc/loki/config.yaml

Restart=always
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOF

📝 NOTE: If the service fails to start, it might be because Loki is already running manually. Kill it using:

ps aux | grep loki
kill <PID>

⚠️ Important​

By default, the Loki configuration uses /tmp for storage:

storage:
  filesystem:
    chunks_directory: /tmp/loki/chunks
    rules_directory: /tmp/loki/rules

You should change the path from the /tmp directory in your config.yaml file. Otherwise, logs will be deleted after the server restarts because /tmp is cleared on reboot.

✅ Recommended Example​

storage:
  filesystem:
    chunks_directory: /var/lib/loki/chunks
    rules_directory: /var/lib/loki/rules

Make sure the directories exist and are writable:

sudo mkdir -p /var/lib/loki/chunks /var/lib/loki/rules
sudo chown -R loki:loki /var/lib/loki

🛠️ Reload and Start Loki Service​

sudo systemctl daemon-reload
sudo systemctl enable loki
sudo systemctl start loki
sudo systemctl status loki

🔍 Verify If Loki Is Running​

Check Loki readiness on port 3100:

curl -s http://localhost:3100/ready

✅ If Loki is working correctly, it should return:

"ready"

🎯 Next Steps​

  • ✅ Integrate Loki with Promtail to collect logs.
  • ✅ Connect it with Grafana for visualization.
  • ✅ Explore Loki’s API for querying logs.

🚀 Install Promtail on Target Machine

👥 Download and Install Promtail​

curl -O -L "https://github.com/grafana/loki/releases/latest/download/promtail-linux-amd64.zip"
sudo apt install unzip
unzip promtail-linux-amd64.zip
sudo mv promtail-linux-amd64 /usr/local/bin/promtail
sudo chmod +x /usr/local/bin/promtail

⚙️ Configure Promtail​

Create config file /etc/promtail/config.yaml:

sudo tee /etc/promtail/config.yaml > /dev/null <<EOF
server:
  http_listen_port: 9080
  grpc_listen_port: 0

positions:
  filename: /var/log/positions.yaml

clients:
  - url: http://<LOKI_SERVER_IP>:3100/loki/api/v1/push

scrape_configs:
  - job_name: "nginx-logs"
    static_configs:
      - targets:
          - localhost
        labels:
          job: "nginx-logs"
          host: "nginx-server"
          __path__: /var/log/nginx/access.log
EOF

🚠 Create a Systemd Service for Promtail​

sudo tee /etc/systemd/system/promtail.service > /dev/null <<EOF
[Unit]
Description=Promtail Log Collector
After=network.target

[Service]
ExecStart=/usr/local/bin/promtail -config.file=/etc/promtail/config.yaml
Restart=always
User=root

[Install]
WantedBy=multi-user.target
EOF

🚠 Start and Enable Promtail​

sudo systemctl daemon-reload
sudo systemctl enable promtail
sudo systemctl start promtail
sudo systemctl status promtail

👉 Promtail is now set up and running! 🎉