Description

This article demonstrates how a resource-filter associated with an PFE IFD telemetry sensor can be composed, verified and used. Although this example is primarily focused on the PFE IFD counters sensor (/junos/system/linecard/interface/), a similar logic can be applied while working with different type of JTI sensors.

Solution

By default, no resource-filters are applied to JTI sensors, therefore all interfaces suitable for exporting the data are considered. Typically, these are:

  • Ethernet interfaces (ge-, xe-, et-);
  • Tunnel interfaces (vt-, lt-, gr-, lsi-);
  • RP encaps/decaps (pe-, pd-), and some others.

Note: For LAG interfaces, stats are exported from the corresponding member links (physical).

There are two approaches for composing a regex used in the resource-filter:

  1. Explicitly specify the interfaces to retrieve stats from. The remaining interfaces won't be considered by the sensor.

    The regex engine is based on the modified regex(3) BSD-library. The following expressions are confirmed to be working:

    • A wildcard "*"

      resource-filter "^ge-.*"                /* Only the GE-interfaces            */
      resource-filter "^ge-0/0/.*"            /* Only the GE-interfaces in MIC 0/0 */

    • A character class "[ ]"

      resource-filter "^ge-0/1/[03]"          /* Only interfaces ge-0/1/0 and ge-0/1/3 */

    • A character class with a range "[ - ]"

      resource-filter "^ge-0/0/[0-3]"         /* Only the first four GE-interfaces in MIC 0/0 */

    • An inverted character class "[^ ]"

      resource-filter "^[a-z][^e]-.*"         /* The second letter in the ifname is not "e" */

    • Alternation

      resource-filter "^(ge|xe|et)-.*"        /* Only Ethernet interfaces * /

  2. Exclude some interfaces from the data reports.

    Note: The operation of negation "!" is not a part of the native regex syntax. Instead, it was added as an extension to the regex parser in 16.1 and only allowed at the very first position in a regular expression.
    When the parser encounters the "!" meta-character in the beginning of a regex, it advances the pointer one symbol further and continues handling the rest of the expression. Once the regex is compiled, its result is negated during the application.

    Examples:

    resource-filter "!(^ps.*)"                  /* Exclude ps-interfaces     */
    resource-filter "!(^(pd|pe|gr|ip)-.*)"      /* Exclude PIM, GRE and IPIP interfaces */

    WARNING: If a resource-filter does not match any interface, no data are exported by the sensor. Thus, failing to create a valid regex will effectively makes the sensor unusable. The following techniques help ensure the regex is composed correctly and yields the expected results.

    A reference configuration:

    services {
        analytics {
            sensor IFD-STATS {
                server-name COLLECTOR_LAB;
                export-name EVERY_30_SEC;
                resource /junos/system/linecard/interface/;
                resource-filter " ge-0/1/[0-1] ";
            }
        }
    }

    A regex can be tested before a resource-filter is applied to a sensor:

    ukern_CLI # test agent filter ${REGEX.EN_US} ${PATTERN.EN_US}

    VMX-0(R2 vty)# test agent filter "^ge-0/1/[ 0-1 ]" "ge-0/1/ 0 "
    Agent Filter: regex: (^ge-0/1/[0-1]) applied to: (ge-0/1/0) == TRUE

    VMX-0(R2 vty)# test agent filter "^ge-0/1/[ 0-1 ]" "ge-0/1/ 1 "
    Agent Filter: regex: (^ge-0/1/[0-1]) applied to: (ge-0/1/1) == TRUE

    VMX-0(R2 vty)# test agent filter "^ge-0/1/[ 0-1 ]" "ge-0/1/ 2 "
    Agent Filter: regex: (^ge-0/1/[0-1]) applied to: (ge-0/1/2) == FALSE

    Once the resource-filter has been applied, the operational status of the sensor can be verified:

    • Get the sensor ID first

    VMX-0(R2 vty)# show agent sensors

     Jvision ID  Name
     ----------  --------------------------------
      539528113  sensor_1002           0(0)
      539528114  sensor_1001           0(0)
      1595622898   IFD-STATS             5000(750)
     2277069355  __default_fabric_sensor__  5000(82)
    [snip]

    • The interfaces considered by the sensor are:

    VMX-0(R2 vty)# show agent sensors id 1595622898 filter
    ge-0/1/0
    ge-0/1/1

    • The data associated with and exported by the sensor

    VMX-0(R2 vty)# show agent sensors id 1595622898
    ID: 1595622898 Type: 1 Name: (IFD-STATS)
    Sensor Data: 779(751) bytes
    Jvision Header: system: R2:198.18.100.2, slot: 0, time: Sep  9 09:26:36.438, sequence_number: 1, sensor_name: IFD-STATS:/junos/system/linecard/interface/:/junos/system/linecard/interface/:PFE, version: 1.1
    Interface = ge-0/1/0 (537)
    [snip]

     In Packets = 7316 (0 pkts/sec) Bytes = 3033543 (0 bytes/sec)
     UPackets = 154505  MPackets = 0 BPackets = 0
     RX Error Packets = 0
     In Pause Packets = 0
     Out Packets = 10746 (0 pkts/sec) Bytes = 8444457 (1 bytes/sec)
     UPackets = 154468  MPackets = 0 BPackets = 0
     TX Error Packets = 0
     Out Pause Packets = 0
    [snip]

    Interface = ge-0/1/1 (538)
    [snip]

     In Packets = 104922 (272 pkts/sec) Bytes = 32969149 (389198 bytes/sec)
     UPackets = 0  MPackets = 0 BPackets = 0
     RX Error Packets = 0
     In Pause Packets = 0
     Out Packets = 66956 (272 pkts/sec) Bytes = 27259260 (389207 bytes/sec)
     UPackets = 0  MPackets = 0 BPackets = 0
     TX Error Packets = 0
     Out Pause Packets = 0
    [snip]

            Export: Interval = 30000 msecs, Payload-size = 5000 bytes, Server = Src: 198.18.100.2:1000, Dst: 198.18.100.1:11017(VRF 0) , Qos = TOS:0x0, Hint:0x40000010, FC:0 PLP:0
            Filter: ge-0/1/[0-1]
            Accounting:
                  2726 total successful reaps, 0 failed/aborted reap(s).
                     1 reaps in latest reporting interval.
                     1 packets in latest reporting interval.
                     2 instances in latest reporting interval.
                  2726 total packets sent.
                  2726 wraps, 1 reap(s) on average to wrap.
    [snip]