Forum Discussion

Cumulonimbus

May 12, 2021

iStats Gauge and String options - any experience?

Hi, When working with iStats, there is an option to configure the metrics as a Counter, Gauge and String. As far as I understand it, the Gauge gives an average value of all values given to it,...

application delivery

iRules

LTM

Dario_Garrido
May 24, 2021
Yes, it's exactly as you said.
An example of decrementing a gauge value is:
istats incr "uri /api gauge curr_reqs" -- -3
Regards,
Dario.

Dario_Garrido

MVP

May 18, 2021

Hello AlexBCT.

Counter, Gauge and String are just measure types, not a format types.

String is a text, and the difference between counter and gauge is bit sutil (similar to counter and gauge difference in SNMP).

F5-BIGIP-LOCAL-MIB::ltmServerSslMaxActiveHandshake."/Common/crypto-client-default-serverssl" = Gauge32: 0
F5-BIGIP-LOCAL-MIB::ltmServerSslStatHandshakeFailures."/Common/serverssl" = Counter64: 0

Counters only increase, but gauge could increase or decrease (it allows you to set a negative increment).

[root@spissa:Active:Standalone] alertd # istats -help
Usage: istats <operation> [-s <segment-filename>] <key> [<value>]
   <operation> is one of: 'set' 'incr' 'get' 'remove' 'dump' 'drop_row'
           'drop_column' 'clear_row'
   <key> is a single quoted argument: "keyspace <table> <column> <value> ... <type> <measure>"
           (like "ltm.pool /Common/mypool counter mystat")
   <type> is one of: 'counter' 'gauge' 'string' 'text' 'signed' 'unsigned' 'bin'
           'dec' 'hex' 'timestamp' 'timeval' 'uinthex'
   <value> must be specified for 'set' and 'incr', and must be an integer for 'incr'
           The <value> for a gauge may be negative.  Use 2 dashes before the
           negative value (like 'incr "... gauge ..." -- -1')

Regards,

Dario.

Twpsyn_
Nimbostratus
May 24, 2021
So conceptually you might use a counter to record say the total connections handled by an iRule (incrementing on client_accept) and a guage to record the current connections (incrementing on client_accept, decrementing on client_closed)?
- Dario_Garrido
  MVP
  May 24, 2021
  Yes, it's exactly as you said.
  An example of decrementing a gauge value is:
  istats incr "uri /api gauge curr_reqs" -- -3
  Regards,
  Dario.
- AlexBCT
  Cumulonimbus
  May 25, 2021
  Ah, makes sense now - I think my understanding that it was taking the average of a bunch of values seems to have been wrong.
  
  Thanks both!