Ping

Overview

Sends a ping message by executing the system ping command and reports the results.

This plugin has two main methods of operation: exec and native. The recommended method is native, which has greater system compatibility and performance.

When using method = "exec", the systems ping utility is executed to send the ping packets.

Most ping command implementations are supported, one notable exception being that there is currently no support for GNU Inetutils ping. You may instead use the iputils-ping implementation:

apt-get install iputils-ping

When using method = "native" a ping is sent and the results are reported in native Go by the agent process, eliminating the need to execute the system ping command.

Configuration

[[inputs.ping]]
  instance_id = "" ## REQUIRED

  ## Hosts to send ping packets to.
  urls = ["example.org"]

  ## Method used for sending pings, can be either "exec" or "native".  When set
  ## to "exec" the systems ping command will be executed.  When set to "native"
  ## the plugin will send pings directly.
  ##
  # method = "native"

  ## Number of ping packets to send per interval.  Corresponds to the "-c"
  ## option of the ping command.
  # count = 3

  ## Time to wait between sending ping packets in seconds.  Operates like the
  ## "-i" option of the ping command.
  # ping_interval = 1.0

  ## If set, the time to wait for a ping response in seconds.  Operates like
  ## the "-W" option of the ping command.
  # timeout = 1.0

  ## If set, the total ping deadline, in seconds.  Operates like the -w option
  ## of the ping command.
  # deadline = 10

  ## Interface or source address to send ping from.  Operates like the -I or -S
  ## option of the ping command.
  # interface = ""

  ## Percentiles to calculate. This only works with the native method.
  # percentiles = [50, 95, 99]

  ## Specify the ping executable binary.
  # binary = "ping"

  ## Arguments for ping command. When arguments is not empty, the command from
  ## the binary option will be used and other options (ping_interval, timeout,
  ## etc) will be ignored.
  # arguments = ["-c", "3"]

  ## Use only IPv6 addresses when resolving a hostname.
  # ipv6 = false

  ## Number of data bytes to be sent. Corresponds to the "-s"
  ## option of the ping command. This only works with the native method.
  # size = 56

File Limit

Since this plugin runs the ping command, it may need to open multiple files per host. The number of files used is lessened with the native option but still many files are used. With a large host list you may receive a too many open files error.

To increase this limit on platforms using systemd the recommended method is to use the “drop-in directory”, usually located at /etc/systemd/system/circonus-unified-agent.service.d.

You can create or edit a drop-in file in the correct location using:

systemctl edit circonus-unified-agent

Increase the number of open files:

[Service]
LimitNOFILE=8192

Restart circonus-unified-agent:

systemctl edit circonus-unified-agent

Linux Permissions

When using method = "native", agent will attempt to use privileged raw ICMP sockets. On most systems, doing so requires CAP_NET_RAW capabilities.

With systemd:

systemctl edit circonus-unified-agent
[Service]
CapabilityBoundingSet=CAP_NET_RAW
AmbientCapabilities=CAP_NET_RAW
systemctl restart circonus-unified-agent

Without systemd:

setcap cap_net_raw=eip /opt/circonus/unified-agent/sbin/circonus-unified-agentd

Reference man 7 capabilities for more information about setting capabilities.

When agent cannot listen on a privileged ICMP socket it will attempt to use ICMP echo sockets. If you wish to use this method you must ensure agent’s group, usually cua, is allowed to use ICMP echo sockets:

sysctl -w net.ipv4.ping_group_range="GROUP_ID_LOW   GROUP_ID_HIGH"

Reference man 7 icmp for more information about ICMP echo sockets and the ping_group_range setting.