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API below is for information purposes only. pr2_computer_monitor is only supported to monitor PR2 computers and systems.

cpu_monitor.py

The CPU Monitor, cpu_monitor.py, monitors the temperature, usage, and NFS status of the host computers. It is launch when a robot launches as part of pr2_core. It publishes to /diagnostics on three status names: "<hostname> CPU Temperatures", "<hostname> CPU Usage", and "<hostname> NFS I/O".

Published Topics

/diagnostics (diagnostic_msgs/DiagnosticArray)

• Diagnostics about the status of the CPU(s).

Parameters

~check_core_temps (boolean, default: False)

• Whether to check core temparatures. Deprecated.

~check_impi_tool (boolean, default: True)

• Whether to use ipmi_tool, which only works on some machines

~enforce_clock_speed (boolean, default: True)

• If clock speed below 2240 MHz and this is engaged, gives warning. Error if speed below 2150 MHz

~load1_threshold (float, default: 5.0)

• Warn if 1 minute load average goes above this threshold.

~load5_threshold (float, default: 3.0)

• Warn if 5 minute load average goes above this threshold.

~check_nfs (boolean, default: False)

• Give statistics on NFS (network filesystem). Deprecated.

~num_cores (int, default: 8)

• Check that we have correct number of cores. If set to <0, disables the check.

Usage

Usage: cpu_monitor.py [--diag-hostname=cX]

Options:
  -h, --help            show this help message and exit
  --diag-hostname=DIAG_HOSTNAME
                        Computer name in diagnostics output (ex: 'c1')

To try it locally:

roslaunch pr2_computer_monitor cpu_monitor.launch

Implementation details

cpumonitor.py uses command line tools to monitor the CPU. These commands are called in timer threads every 10 seconds or so to keep load down.

hd_monitor.py

The HD Monitor, hd_monitor.py, monitors temperature and disk usage of the host's hard drive. It is launch on the PR2 as part of pr2_core. It publishes to /diagnostics on two status names: "<hostname> HD Temperature" and "<hostname> HD Usage" (optional).

Published Topics

/diagnostics (diagnostic_msgs/DiagnosticArray)

• Diagnostics about the status of the HD(s).

Parameters

~no_hd_temp_warn (boolean, default: False)

• If True, then don't warn if hard drive temp is too hot. Deprecated.

Usage

Since many robots use a network filesystem and have the same files on all machines, it doesn't make sense to monitor drive space on all drives.

Usage: hd_monitor.py [--diag-hostname=cX]

Options:
  -h, --help            show this help message and exit
  --diag-hostname=DIAG_HOSTNAME
                        Computer name in diagnostics output (ex: 'c1')

If the HOME_DIR directory above isn't specified, the monitor will not check disk space remaining.

To try it locally:

roslaunch pr2_computer_monitor hd_monitor.launch

Implementation details

hd_monitor.py uses command line tools to monitor the HD.

hd_monitor.py will only check the disk usage if the home directory argument is set from the command line.

To check hard drive temperature, it opens a socket to hddtemp, a daemon program running on most Linux machines. You can check if hddtemp is working by running:

$ netcat localhost 7634
|/dev/sda|Hitachi HDT725032VLA360|43|C|

ntp_monitor.py

The NTP Monitor, ntp_monitor.py, monitors the offset between computer clocks on a robot, if the robot uses Network Time Protocol (NTP). It uses ntpdate to check the offset. It publishes to /diagnostics with the names "NTP offset from <hostname> to <server>" and "NTP self-offset for <hostname>".

Published Topics

/diagnostics (diagnostic_msgs/DiagnosticArray)

• Diagnostics about the status of NTP.

Usage

Usage: ntp_monitor ntp-hostname []

Options:
  -h, --help            show this help message and exit
  --offset-tolerance=OFFSET-TOL
                        Offset from NTP host
  --self_offset-tolerance=SELF_OFFSET-TOL
                        Offset from self
  --diag-hostname=DIAG_HOSTNAME
                        Computer name in diagnostics output (ex: 'c1')

To try it locally:

roslaunch pr2_computer_monitor ntp_monitor.launch

Implementation Details

ntp_monitor.py uses ntpdate to check the offset in clocks, using the NTP protocol.

ntpdate -q <server>
ntpdate -q <hostname>

Give the offset from the NTP server, and the computer's self offset.

Computer Clocks and Self-Offset

Each computer has two times: the time chrony thinks it is, and the system time. When they disagree, chrony slowly slews the system time until they match again. When you do ntpdate -q <server> you compare host's chrony time with the local system time. Doing ntpdate -q <hostname> allows you to verify that the chrony time and the system time match.

nvidia_temp.py

This node monitors an NVIDIA GPU for temperature and usage statistics.

Published Topics

/diagnostics (diagnostic_msgs/DiagnosticArray)

• Diagnostics about the status of NTP.

gpu_status (pr2_msgs/GPUStatus)

• Machine readable status of the GPU

Usage

Usage: nvidia_temp.py

(No command-line arguments).

Implementation Details

The nvidia_temp.py script uses the command:

sudo nvidia-smi -a

to check the status of the GPU. This command must work without a password. Configure your sudoers file accordingly.

network_detector

The network detector, network_detector, monitors a given network interface (such as "eth0") and publishes whether it is up and running (connected) or not. The purpose is to detect wired network connections, so the robot can avoid driving and yanking out its network cable. Finding which network interface (if any) really represents a wired connection must be done by the person who configures the robot. On the PR2, this is "wan0" on computer C1.

Published Topics

/network/connected (std_msgs/Bool)

• True if the interface exists and is connected, false otherwise.

Parameters

~interface_name (string, default: none)

• Name of the network interface to monitor, for example "eth0" or "wan0".

Usage

Here is a typical launch file entry for running it:

  <node pkg="pr2_computer_monitor" type="network_detector" name="network_detector" output="screen">
    <param name="interface_name" value="wan0"/>
  </node>

Installation and setup

With proper system dependencies, pr2_computer_monitor can work on almost any linux system. Use rosdep to install required packages from the operating system:

$ rosdep install pr2_computer_monitor

Verifying hddtemp Daemon

It's a good idea to verify the installation of hddtemp. To contact hddtemp (which measures hard drive temperature), pr2_computer_monitor opens a socket to the hddtemp daemon.

First, verify that the hddtemp daemon is running.

$ netcat localhost 7634

This opens a socket to the daemon, which by default runs on port 7634. You should see something like:

|/dev/sda|Hitachi HDT725032VLA360|41|C|

If hddtemp isn't up and running, start it by typing:

sudo hddtemp -d /dev/sda

This will start it in daemon mode. Replace "/dev/sda" above with the name of your hard drive if it's different.

Configuring ipmitool

Now, check if you have ipmitool installed correctly. If you choose not to use ipmitool to monitor CPU temperature and fan speed, disable it with ~check_ipmi_tool parameter to False.

sudo ipmitool sdr

If this command returns with an error (below), then you will need to disable the ipmitool checks using the ~check_ipmi_tool parameter.

$ sudo ipmitool sdr
Could not open device at /dev/ipmi0 or /dev/ipmi/0 or /dev/ipmidev/0: No such file or directory
Get Device ID command failed
Unable to open SDR for reading

The ipmitool command needs to work properly without a password. If the above command asks for a "sudo" password, you'll need to edit the sudoers file:

sudo visudo

Add the following line to use ipmitool without typing your password:

sudo ipmitool sdr ALL NOPASSWD

Other Configuration

If your computers uses NFS, then you should enable the ~check_nfs parameter for CPU monitor. The NFS status messages will have no data if not enabled.

CPU monitor will warn if the CPU cores start throttling below 2240 MHz. This is appropriate for the PR2, but if your computer is different, disable the ~enforce_clock_speed parameter.

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