Sensu Plugins Network Checks Plugin

• Overview
• Files
• Usage examples
• Configuration
  • Sensu Go
    • Asset registration
    • Asset definition
    • Check definition
  • Sensu Core
    • Check definition
• Installation from source
• Additional notes
• Contributing

Overview

This plugin provides native network instrumentation for monitoring and metrics collection, including hardware, TCP response, RBLs, whois, port status, and more.

Files

• bin/check-banner.rb
• bin/check-jsonwhois-domain-expiration.rb
• bin/check-mtu.rb
• bin/check-multicast-groups.rb
• bin/check-netfilter-conntrack.rb
• bin/check-netstat-tcp.rb
• bin/check-ping.rb
• bin/check-ports-bind.rb
• bin/check-ports-nmap.rb
• bin/check-ports.rb
• bin/check-rbl.rb
• bin/check-socat.rb
• bin/check-whois-domain-expiration-multi.rb
• bin/check-whois-domain-expiration.rb
• bin/metrics-interface.rb
• bin/metrics-net.rb
• bin/metrics-netif.rb
• bin/metrics-netstat-tcp.rb
• bin/metrics-ping.rb
• bin/metrics-sockstat.rb

check-banner
Connects to a TCP port on one or more hosts, reads until a char (EOF, EOL, etc), and tests output against a pattern.

check-jsonwhois-domain-expiration
Checks domain expiration dates using the https://jsonwhois.com API.

check-mtu
Checks maximum transmission unit (MTU) of a network interface. In many setups, MTUs are tuned and MTU mismatches cause issues. Having a check for MTU settings helps catch these mistakes. Also, some instances in Amazon EC2 have a default MTU size of 9,000 bytes, which is undesirable in some environments. This check can catch undesirable setups.

check-multicast-groups
Checks whether specific multicast groups are configured on specific interfaces. Requires the netstat command.

check-netfilter-conntrack
Checks Netfilter connection tracking table condition.

check-netstat-tcp
Alert based on thresholds of discrete TCP socket states reported by netstat.

check-ping
Ping check script for Sensu.

check-ports-bind
Connects to a TCP/UDP address:port to check whether open or closed.

check-ports-nmap
Fetches port status using nmap. Catches bad network access control lists (ACLs) and service down events for network resources.

check-ports
Connects to a TCP/UDP port on one or more ports check whether ropen or closed. This check now uses a TCPSocket, not nmap (check-ports-nmap above uses nmap).

check-rbl
Checks whether an IP is blacklisted in the common DNS blacklists or a list you add.

check-socat
Inspects sockets, such as checking whether socat can receive particular a UDP multicast packet within a certain number of seconds or whether a UPD multicast packet contains an expected packet.

check-whois-domain-expiration-multi
Checks expiration dates for multiple domains using the whois gem.

check-whois-domain-expiration
Checks a domain's expiration dates using the whois gem.

metrics-interface
Provides interface metrics.

metrics-net
Fetches metrics from all interfaces on the box using the /sys/class interface.

metrics-netif
Fetches network interface throughput metrics.

metrics-netstat-tcp
Fetches metrics on TCP socket states from netstat. Particularly useful on high-traffic web or proxy servers with large numbers of short-lived TCP connections coming and going.

metrics-ping
Pings a host and outputs ping statistics.

metrics-sockstat
Parses /proc/net/sockstat and outputs all fields as metrics.

Usage examples

Help

check-banner.rb

Usage: check-banner.rb (options)
    -c, --count NUMBER               Number of successful matches, default(1)
    -C, --critmessage MESSAGE        Custom critical message to send
    -e, --exclude_newline            Exclude newline character at end of write STRING
    -H, --hostnames HOSTNAME(S)      Host(s) to connect to, comma seperated
    -O, --okmessage MESSAGE          Custom ok message to send
    -q, --pattern PAT                Pattern to search for
    -p, --port PORT
    -r, --readtill CHAR              Read till CHAR is reached
    -S, --ssl                        Enable SSL socket for secure connection
    -t, --timeout SECS               Connection timeout
    -w, --write STRING               write STRING to the socket

metrics-interface.rb

Usage: metrics-interface.rb (options)
    -x INTERFACE[,INTERFACE],        List of interfaces to exclude
        --exclude-interface
    -i INTERFACE[,INTERFACE],        List of interfaces to include
        --include-interface
    -s, --scheme SCHEME              Metric naming scheme, text to prepend to metric

Configuration

Sensu Go

Asset registration

Assets are the best way to make use of this plugin. If you're not using an asset, please consider doing so! If you're using sensuctl 5.13 or later, you can use the following command to add the asset:

sensuctl asset add sensu-plugins/sensu-plugins-network-checks

If you're using an earlier version of sensuctl, you can download the asset definition from this project's Bonsai asset index page.

Asset definition

---
type: Asset
api_version: core/v2
metadata:
  name: sensu-plugins-network-checks
spec:
  url: https://assets.bonsai.sensu.io/c90a2b1335ee9cda57046bd4551b303098a98237/sensu-plugins-network-checks_4.1.0_centos_linux_amd64.tar.gz
  sha512: 0fe990e4eb53c308c6245d8ac8cc7268d34e3235d5188ecda3a7308889a09b8b722a77f57169d6d9a7c2f1bf3b523fcdcb618aeb4cd6b83bd74feb3683d721b7

Check definition

---
type: CheckConfig
spec:
  command: "check-banner.rb"
  handlers: []
  high_flap_threshold: 0
  interval: 10
  low_flap_threshold: 0
  publish: true
  runtime_assets:
  - sensu-plugins/sensu-plugins-network-checks
  - sensu/sensu-ruby-runtime
  subscriptions:
  - linux

Sensu Core

Check definition

{
  "checks": {
    "check-banner": {
      "command": "check-banner.rb",
      "subscribers": ["linux"],
      "interval": 10,
      "refresh": 10,
      "handlers": ["influxdb"]
    }
  }
}

Installation from source

Sensu Go

See the instructions above for asset registration.

Sensu Core

Install and setup plugins on Sensu Core.

Additional notes

Sensu Go Ruby Runtime Assets

The Sensu assets packaged from this repository are built against the Sensu Ruby runtime environment. When using these assets as part of a Sensu Go resource (check, mutator, or handler), make sure to include the corresponding Sensu Ruby Runtime Asset in the list of assets needed by the resource.

Contributing

See CONTRIBUTING.md for information about contributing to this plugin.