Client Telemetry Aggregators
It is possible to configure the client to send in regular intervals the performance counters listed by cvmfs_talk internal affairs
.
By default, an aggregator is available that exposes the counters in InfluxDB data format.
It can easily be replaced by any other aggregator in a form of a source code plugin.
Independent of the aggregator following 2 client parameters must be set:
CVMFS_TELEMETRY_SEND=ON
CVMFS_TELEMETRY_RATE=<rate in seconds> # minimum send rate >= 5 sec
Influx Telemetry Aggregator
The Influx Telemetry Aggregator sends per timestamp two versions of the counters:
their absolute values and the delta between two timestamps to a socket.
For this, the measurement name given by CVMFS_INFLUX_METRIC_NAME
is extended with either _absolute
or _delta
.
Mandatory client parameters for the Influx Telemetry Aggregator are
CVMFS_INFLUX_HOST=localhost # IP address
CVMFS_INFLUX_PORT=8092 # Port
CVMFS_INFLUX_METRIC_NAME=<measurement name> # "Table" name
And optional parameters are
CVMFS_INFLUX_EXTRA_TAGS="some_tag=42,some_tag2=27" # always included
CVMFS_INFLUX_EXTRA_FIELDS="somefield=3" # not included in delta
The general layout of the data send is
# for absolute
CVMFS_INFLUX_METRIC_NAME_absolute,repo=@fqrn,CVMFS_INFLUX_EXTRA_TAGS countername=value,...,CVMFS_INFLUX_EXTRA_FIELDS timestamp
# for delta (no CVMFS_INFLUX_EXTRA_FIELDS)
CVMFS_INFLUX_METRIC_NAME_delta,repo=@fqrn,CVMFS_INFLUX_EXTRA_TAGS countername=value_new - value_old,... timestamp
Warning
In the output, counters are only included if they have been used at least once (value != 0). And for the very first measurement no delta values are available.
Writing Your Own Aggregator
The TelemetryAggregator
base class consists of a loop that for each time step
snapshots the counters (saved to counters_
), and calls PushMetrics()
.
PushMetrics()
needs to be overwritten by your own aggregator to perform all manipulations
needed for the counters and the sending/storing of the counters.
To write your own aggregator you need the following parts:
Your aggregator must inherit from
TelemetryAggregator
Your aggregator’s constructor must take care of additional client parameters needed. In case your object is incorrectly constructed,
is_zombie_
MUST be set totrue
.Your aggregator must overwrite
PushMetrics()
Create a new value for your aggregator in enum
TelemetrySelector
Add your aggregator inside the
Create()
ofTelemetryAggregator
using the newly created value ofTelemetrySelector
Change in
mountpoint.cc
theTelemetrySelector
used inperf::TelemetryAggregator::Create
Note
Please feel free to contribute your aggregator to the CVMFS project, so we can expand the number of available aggregators to all users.