Heartbeat Microservice User Documentation

User Documentation for heartbeat Microservice
Issue-ID: DCAEGEN2-280

Change-Id: I158680b11b5d5de4a0d58f4d2f03816e2b1941fc
Signed-off-by: PrakashH <pbhandar@techmahindra.com>

1 files changed, 47 insertions, 0 deletions

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+.. This work is licensed under a Creative Commons Attribution 4.0 International License.

+.. http://creativecommons.org/licenses/by/4.0

+

+.. _architecture:

+

+High-level architecture of Heartbeat Microservice

+=================================================

+

+**Heartbeat Microservice**’s startup script (misshtbtd.py) gets the

+configuration from CBS and parses these entries and saves them in the

+postgres database having table name **vnf_table_1**. Each entry in the

+configuration is for a particular eventName. Each entry has missed

+heartbeat count, heartbeat interval, Control loop name etc. along with

+many other parameters. 

+

+Whenever a heartbeat event is received, the sourceName, lastEpochTime

+and other information is stored in another postgres database having

+table name **vnf_table_2**. It is designed to process the heartbeat event

+having different sourceNames having same eventName. In such case,

+sourceName count is maintained in vnf_table_1 which would give number of

+SouceNames that have same eventName. As and when new sourceName is

+received, sourceName count is incremented in vnf_table_1

+

+The heartbeat Microservice is designed to support multiple instances of

+HB Microservice to run simultaneously. The first instance of the HB

+Microservice would assume the role of active instance, and instances

+that started running later would become inactive instances. If the

+active HB microservice is not responding or killed, the inactive HB

+instance would take over the active role. To achieve this functionality,

+one more postgres table **hb_common** is introduced which has parameters

+specific to active instances such as process id/hostname of the active

+instance, last accessed time updated by active instance.

+

+Heartbeat Microservice supports the periodic download of CBS

+configuration. The periodicity of download can be configured.

+

+Heartbeat Microservice also supports the download of CBS configuration

+whenever configuration changes. Here Docker container would call the

+function/method to download the CBS configuration.

+

+The heartbeat microservice has 2 states

+

+**Reconfiguration state**– Download configuration from CBS and update

+the vnf_table_1 is in progress.

+

+**Running state** – Normal working that comprises of receiving of HB

+events and sending of control loop event if required conditions are met.