[ovs-dev] [PATCH v4 0/7] Add OVS DPDK keep-alive functionality.

[Bhanuprakash Bodireddy]

Keepalive feature is aimed at achieving Fastpath Service Assurance
in OVS-DPDK deployments. It adds support for monitoring the packet
processing cores(PMD thread cores) by dispatching heartbeats at regular
intervals. Incase of heartbeat misses additional health checks are
enabled on the PMD thread to detect the failure and the same shall be
reported to higher level fault management systems/frameworks.

The implementation uses OVSDB for reporting the health of the PMD threads.
Any external monitoring application can read the status from OVSDB at 
regular intervals (or) subscribe to the updates in OVSDB so that they get
notified when the changes happen on OVSDB.

keepalive info struct is created and initialized for storing the
status of the PMD threads. This is initialized by main thread(vswitchd)
as part of init process and will be periodically updated by 'keepalive'
thread. keepalive feature can be enabled through below OVSDB settings.

    enable-keepalive=true
      - Keepalive feature is disabled by default.

    keepalive-interval="5000"
      - Timer interval in milliseconds for monitoring the packet
        processing cores.

When KA is enabled, 'ovs-keepalive' thread shall be spawned that wakes
up at regular intervals to update the timestamp and status of pmd cores
in keepalive info struct. This information shall be read by vswitchd thread
and write the status in to 'keepalive' column of Open_vSwitch table in OVSDB.

An external monitoring framework like collectd with ovs events support
can read (or) subscribe to the datapath status changes in ovsdb. When the state
is updated, the collectd shall be notified and will eventually relay the status
to ceilometer service running in the controller. Below is the high level
overview of deployment model.

    Compute Node            Controller            Compute Node

    Collectd  <----------> Ceilometer <-------->   Collectd

    OvS DPDK                                       OvS DPDK

    +-----+
    | VM  |
    +--+--+
    \---+---/
    |
    +--+---+       +------------+----------+     +------+-------+
    | OVS  |-----> |   ovsevents plugin    | --> |   collectd   |
    +--+---+       +------------+----------+     +------+-------+

    +------+-----+     +---------------+------------+     |
    | Ceilometer | <-- | collectd ceilometer plugin |  <---
    +------+-----+     +---------------+------------+

github: The patches can be found here:
  https://github.com/bbodired/ovs (Last master commit e7cd8c363)

Performance impact:
  No noticeable performance or latency impact is observed with
  KA feature enabled.

-------------------------------------------------
v3 -> v4
  * Split the functionality in to 2 parts. This patch series only updates
    PMD status to OVSDB. The incremental patch series to handle false positives,
    negatives and more checking and stats. 
  * Remove code from netdev layer and dependency on rte_keepalive lib.
  * Merged few patches and simplified the patch series.
  * Timestamp in human readable form.

v2 -> v3
  * Rebase.
  * Verified with dpdk-stable-17.05.1 release.
  * Fixed build issues with MSVC and cross checked with appveyor.

v1 -> v2
  * Rebase
  * Drop 01/20 Patch "Consolidate process related APIs" of V1 as it
    is already applied as separate patch.

RFCv3 -> v1
  * Made changes to fix failures in some unit test cases.
  * some more code cleanup w.r.t process related APIs.

RFCv2 -> RFCv3
  * Remove POSIX shared memory block implementation (suggested by Aaron).
  * Rework the logic to register and track threads instead of cores. This way
    in the future any thread can be registered to KA framework. For now only PMD
    threads are tracked (suggested by Aaron).
  * Refactor few APIs and further clean up the code.
   
RFCv1 -> RFCv2
  * Merged the xml and schema commits to later commit where the actual
    implementation is done(suggested by Ben).
  * Fix ovs-appctl keepalive/* hang issue when KA disabled.
  * Fixed memory leaks with appctl commands for keepalive/pmd-health-show,
    pmd-xstats-show.
  * Refactor code and fixed APIs dealing with PMD health monitoring.


Bhanuprakash Bodireddy (7):
  process: Extend get_process_info() for additional fields.
  Keepalive: Add initial keepalive support.
  dpif-netdev: Register packet processing cores to KA framework.
  dpif-netdev: Enable heartbeats for DPDK datapath.
  keepalive: Retrieve PMD status periodically.
  bridge: Update keepalive status in OVSDB.
  keepalive: Add support to query keepalive status and statistics.

 lib/automake.mk            |   2 +
 lib/dpif-netdev.c          |  78 +++++++
 lib/keepalive.c            | 536 +++++++++++++++++++++++++++++++++++++++++++++
 lib/keepalive.h            | 107 +++++++++
 lib/process.c              |  43 ++--
 lib/process.h              |   2 +
 lib/util.c                 |  23 ++
 lib/util.h                 |   2 +
 vswitchd/bridge.c          |  29 +++
 vswitchd/vswitch.ovsschema |   8 +-
 vswitchd/vswitch.xml       |  49 +++++
 11 files changed, 857 insertions(+), 22 deletions(-)
 create mode 100644 lib/keepalive.c
 create mode 100644 lib/keepalive.h

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2.4.11