magenta-aps / smem-prometheus-exporter

Prometheus Metrics exporter for shared memory metrics via smem

Shared Memory Prometheus Exporter

Prometheus exporter for shared shared memory metrics via smem. Shared memory details are picked up from the /proc filesystem and processed.

Similar to the mongodb_exporter and node_exporter this exporter has been implemented as a standalone-service to make reuse easier across different platforms and hosts.

Building

wget https://www.selenic.com/smem/download/smem-1.4.tar.gz
tar -xzvf smem-1.4.tar.gz
mv smem-1.4 smem
mv smem/smem smem/smem.py
echo "from smem import *" > smem/__init__.py

This downloads the latest release of smem, and configures it to be used as a python library.

Running

python smem_exporter.py

Upon which a full smem default run will be printed, followed by:

Starting HTTPD on 0.0.0.0:8172

After which the metrics endpoint is available at:

• http://localhost:8172/metrics

Output

Navigating to the metrics url, should produce output alike the following:

# HELP smem_map Memory usage maps
# TYPE smem_map gauge
smem_map{map="/usr/lib/x86_64-linux-gnu/libxcb-render.so.0.0.0",reading_type="uss"} 100.0
smem_map{map="/usr/share/fonts/type1/gsfonts/n019063l.pfb",reading_type="vss"} 612.0
...
# HELP smem_user Memory usage by user
# TYPE smem_user gauge
smem_user{reading_type="count",user="user",user_id="1000"} 62.0
smem_user{reading_type="pss",user="user",user_id="1000"} 2.475652e+06
...
# HELP smem_system Memory usage for the system
# TYPE smem_system gauge
smem_system{area="free memory",reading_type="noncache"} 0.0
smem_system{area="kernel image",reading_type="noncache"} 0.0
...
# HELP smem_pid Memory usage by process
# TYPE smem_pid gauge
smem_pid{command="/usr/bin/dbus-daemon ...",pid="7888",reading_type="pss",user="user",user_id="1000"} 459.0
smem_pid{command="/usr/bin/python ...",pid="8610",reading_type="maps",user="user",user_id="1000"} 1245.0
...

Along with the default entries for python and process.

The following metrics are provided:

• smem_map exposes memory maps and shared memory regions, labeled by path and reading type.
• smem_user exposes memory usage for users, labeled by user, user_id and reading type.
• smem_system exposes memory areas for the system, labeled by area and reading_type.
• smem_pid exposes memory usage for processes, labeled by command, pid, user, user_id and reading_type.

Limitations

While running as non-root smem can only query so much information from /proc/. As such this exporter can only export so much information when running as non-root.

To work around this, either:

• Run the exporter as root (bad solution), or
• mount /proc with the gid option and add the export user to the corresponding group.

Future considerations

Below follows a list of ideas for future improvements:

• Adapt to futurization-smem?
• Support commandline flags via argparse?
  • Support for enabling / disabling entire exporters (map, user, system, pid).
  • Support for enabling / disabling based upon labels.
  • Support truncating long commands with ellipsis.
  • Support transforming long commands into just the executable name.
    • Alternatively adding a new label just for executable name might do.
• Utilize Custom Collectors instead of Gauge + resetting.