Telegraf Agent

Overview

This role installs and configures the Telegraf monitoring agent on Linux systems for collecting and forwarding system metrics to InfluxDB. It uses a two-tier configuration approach with a main config file containing agent settings, InfluxDB output, and common input plugins, plus host-specific configs for specialized inputs like Docker monitoring, SNMP polling, etc. The role supports both RedHat and Debian systems, automatically manages repository configuration, validates Telegraf configuration before deploying, and handles service management.

What This Role Does

1. Configure InfluxData Repository

RedHat/CentOS:

• Adds InfluxData yum repository
• Installs GPG key for package verification

Debian/Ubuntu:

• Adds InfluxData apt repository
• Installs GPG key

2. Install Telegraf Package

• Installs telegraf package from InfluxData repository.

3. Deploy Main Configuration

File: /etc/telegraf/telegraf.conf

Content:

• Agent settings (interval, flush, buffer)
• InfluxDB output configuration
• Common input plugins (always enabled):
  • CPU metrics
  • Disk usage
  • Disk I/O
  • Kernel statistics
  • Memory usage
  • Processes
  • Swap usage
  • System load/uptime
  • Network interfaces
  • Network statistics

4. Deploy Host-Specific Configurations

Directory: /etc/telegraf/telegraf.d/

Conditional configs (based on enabled flags):

• docker.conf: Docker monitoring (enable_docker_input: true)
• temp.conf: Temperature sensors (enable_temp_input: true)
• interrupts.conf: Interrupt monitoring (enable_interrupts_input: true)
• sysctl.conf: Sysctl monitoring (enable_sysctl_input: true)
• snmp_synology.conf: Synology SNMP (enable_snmp_synology: true)
• snmp_zyxel.conf: Zyxel AP SNMP (enable_snmp_zyxel_ap: true)

5. Add Telegraf to Docker Group (if Docker enabled)

If telegraf_agent_enable_docker_input: true:

• Adds telegraf user to docker group
• Allows Telegraf to access Docker socket
• Restarts Telegraf to apply group membership

6. Validate Configuration

Before restarting Telegraf:

• Runs telegraf --config /etc/telegraf/telegraf.conf --test
• Validates configuration syntax
• Fails deployment if config invalid

7. Enable and Start Service

• Enables Telegraf service on boot
• Starts or restarts Telegraf service
• Service runs as telegraf user

Role Variables

Variable	Description
vault_influxdb_telegraf_password	InfluxDB password for the Telegraf user (from vault)
telegraf_agent_service_name	Telegraf systemd service name
telegraf_agent_interval	Metrics collection interval
telegraf_agent_round_interval	Round collection interval to the configured interval
telegraf_agent_metric_batch_size	Maximum metrics per write batch
telegraf_agent_metric_buffer_limit	Maximum metrics to buffer per output
telegraf_agent_collection_jitter	Random jitter added to collection interval
telegraf_agent_flush_interval	Flush interval for all outputs
telegraf_agent_flush_jitter	Random jitter added to flush interval
telegraf_agent_precision	Timestamp precision (empty = no rounding)
telegraf_agent_influxdb_url	InfluxDB server URL
telegraf_agent_influxdb_database	InfluxDB database name
telegraf_agent_influxdb_retention_policy	InfluxDB retention policy name
telegraf_agent_influxdb_username	InfluxDB username
telegraf_agent_cpu_percpu	Collect per-CPU metrics
telegraf_agent_cpu_totalcpu	Collect total CPU metrics
telegraf_agent_cpu_collect_cpu_time	Collect CPU time metrics
telegraf_agent_cpu_report_active	Report active CPU metrics
telegraf_agent_cpu_core_tags	Add core tags to CPU metrics
telegraf_agent_disk_ignore_fs	Filesystem types to exclude from disk metrics
telegraf_agent_enable_docker_input	Enable Docker container monitoring
telegraf_agent_docker_endpoint	Docker socket path for monitoring
telegraf_agent_docker_group	OS group to add telegraf user to for Docker access
telegraf_agent_enable_snmp_synology	Enable Synology NAS SNMP monitoring
telegraf_agent_snmp_synology_agents	List of Synology NAS SNMP agent addresses
telegraf_agent_snmp_synology_interval	SNMP collection interval for Synology
telegraf_agent_snmp_synology_timeout	SNMP request timeout for Synology
telegraf_agent_snmp_synology_retries	SNMP request retry count for Synology
telegraf_agent_snmp_synology_version	SNMP protocol version for Synology
telegraf_agent_snmp_synology_community	SNMP community string for Synology
telegraf_agent_snmp_synology_max_repetitions	SNMP max repetitions for bulk requests
telegraf_agent_snmp_synology_name	Measurement name for Synology SNMP data

Notes

• Enable host-specific inputs in host_vars (e.g., telegraf_agent_enable_docker_input: true on Docker hosts)
• Docker monitoring requires Telegraf user added to the docker group
• Common inputs (interrupts, sysctl, temp) are baked into the base config template and always enabled
• SNMP monitoring for Synology requires community strings in Ansible Vault
• Configuration is validated (telegraf --test) before deployment