Connect Fiware IoT Agent to sharded MongoDB

Question

I am using to following docker-compose file to setup my sharded MongoDB which has 3 shards, 3 config servers and 2 router instances:

version: "3.5"
services:

  mongorsn1:
    container_name: mongors1n1
    hostname: mongors1n1
    image: mongo
    command: mongod --shardsvr --replSet mongors1 --dbpath /data/db --port 27017
    ports:
      - 27017:27017
    expose:
      - "27017"
    environment:
      TERM: xterm
    volumes:
      - /etc/localtime:/etc/localtime:ro
      - /mongo_cluster/data1:/data/db

  mongors1n2:
    container_name: mongors1n2
    hostname: mongors1n2
    image: mongo
    command: mongod --shardsvr --replSet mongors1 --dbpath /data/db --port 27017
    ports:
      - 27027:27017
    expose:
      - "27017"
    environment:
      TERM: xterm
    volumes:
      - /etc/localtime:/etc/localtime:ro
      - /mongo_cluster/data2:/data/db

  mongors1n3:
    container_name: mongors1n3
    hostname: mongors1n3
    image: mongo
    command: mongod --shardsvr --replSet mongors1 --dbpath /data/db --port 27017
    ports:
      - 27037:27017
    expose:
      - "27017"
    environment:
      TERM: xterm
    volumes:
      - /etc/localtime:/etc/localtime:ro
      - /mongo_cluster/data3:/data/db
      
  mongocfg1:
    container_name: mongocfg1
    image: mongo
    command: mongod --configsvr --replSet mongors1conf --dbpath /data/db --port 27017
    environment:
      TERM: xterm
    expose:
      - "27017"
    volumes:
      - /etc/localtime:/etc/localtime:ro
      - /mongo_cluster/config1:/data/db
      
  mongocfg2:
    container_name: mongocfg2
    image: mongo
    command: mongod --configsvr --replSet mongors1conf --dbpath /data/db --port 27017
    environment:
      TERM: xterm
    expose:
      - "27017"
    volumes:
      - /etc/localtime:/etc/localtime:ro
      - /mongo_cluster/config2:/data/db
      
  mongocfg3:
    container_name: mongocfg3
    image: mongo
    command: mongod --configsvr --replSet mongors1conf --dbpath /data/db --port 27017
    environment:
      TERM: xterm
    expose:
      - "27017"
    volumes:
      - /etc/localtime:/etc/localtime:ro
      - /mongo_cluster/config3:/data/db

  mongos1:
    container_name: mongos1
    image: mongo
    hostname: mongos1
    depends_on:
      - mongocfg1
      - mongocfg2
    command: mongos --configdb mongors1conf/mongocfg1:27017,mongocfg2:27017,mongocfg3:27017 --port 27017
    ports:
      - 27019:27017
    expose:
      - "27017"
    volumes:
      - /etc/localtime:/etc/localtime:ro

  mongos2:
    container_name: mongos2
    image: mongo
    hostname: mongos2
    depends_on:
      - mongocfg1
      - mongocfg2
    command: mongos --configdb mongors1conf/mongocfg1:27017,mongocfg2:27017,mongocfg3:27017 --port 27017
    ports:
      - 27020:27017
    expose:
      - "27017"
    volumes:
      - /etc/localtime:/etc/localtime:ro

As you can see it is up and running correctly.

docker exec -it mongos1 bash -c "echo 'sh.status()' | mongo "

MongoDB shell version v4.4.6
connecting to: mongodb://127.0.0.1:27017/?compressors=disabled&gssapiServiceName=mongodb
Implicit session: session { "id" : UUID("f00e3ac7-e114-40b3-b7f8-0e5cf9c56e10") }
MongoDB server version: 4.4.6
--- Sharding Status ---
  sharding version: {
        "_id" : 1,
        "minCompatibleVersion" : 5,
        "currentVersion" : 6,
        "clusterId" : ObjectId("609e21145937100b3f006e20")
  }
  shards:
        {  "_id" : "mongors1",  "host" : "mongors1/mongors1n1:27017,mongors1n2:27017,mongors1n3:27017",  "state" : 1 }
  active mongoses:
        "4.4.6" : 2
  autosplit:
        Currently enabled: yes
  balancer:
        Currently enabled:  yes
        Currently running:  no
        Failed balancer rounds in last 5 attempts:  0
        Migration Results for the last 24 hours:
                No recent migrations
  databases:
        {  "_id" : "config",  "primary" : "config",  "partitioned" : true }
bye

Now here is the docker-compose file I use to connect Orion and the IoT Agent to my MongoDB shards.

version: "3.5"
services:

  orion:
    image: atos/smbt/orion:2.5.2
    hostname: orion
    container_name: orion
    restart: unless-stopped
    ports:
      - "1026:1026"
    entrypoint:
      - /usr/bin/contextBroker
      - -fg 
      - -multiservice
      - -ngsiv1Autocast
      - -corsOrigin
      - __ALL
    command: -dbhost mongors1n1:27017,mongors1n2:27027,mongors1n3:27037 -rplSet mongors1 -logLevel ERROR -noCache
    healthcheck:
      test: curl --fail -s http://orion:1026/version || exit 1
    networks:
      - fiware_mongo_sharding_default
  
  iot-agent:
    image: atos/smbt/iotagent-ul:1.15.0
    hostname: iot-agent
    container_name: iot-agent
    restart: unless-stopped
    expose:
        - "4041"
        - "7896"
    ports:
        - "4041:4041"
        - "7896:7896"
    environment:
        - IOTA_CB_HOST=orion
        - IOTA_CB_PORT=1026
        - IOTA_NORTH_PORT=4041
        - IOTA_REGISTRY_TYPE=mongodb
        - IOTA_LOG_LEVEL=ERROR
        - IOTA_TIMESTAMP=true
        - IOTA_CB_NGSI_VERSION=v2
        - IOTA_AUTOCAST=true
        - IOTA_MONGO_HOST=mongors1n1
        - IOTA_MONGO_PORT=27017
        - IOTA_MONGO_DB=iotagentul
        - IOTA_HTTP_PORT=7896
        - IOTA_PROVIDER_URL=http://iot-agent:4041
    networks:
      - fiware_mongo_sharding_default      
  
networks:
  fiware_mongo_sharding_default:
    external: true

Orion is connected to MongoDB but with the IoT Agent I get the following error message.

time=2021-05-14T07:51:51.086Z | lvl=ERROR | corr=28202651-30e1-48dc-88a9-53de603e7e6d | trans=28202651-30e1-48dc-88a9-53de603e7e6d | op=IoTAgentNGSI.DbConn | from=n/a | srv=n/a | subsrv=n/a | msg=MONGODB-001: Error trying to connect to MongoDB: MongoNetworkError: failed to connect to server [mongos1:27019] on first connect [MongoNetworkError: connect ECONNREFUSED 172.20.0.9:27019] | comp=IoTAgent

I have tried different things such as:

- IOTA_MONGO_HOST=mongos1
- IOTA_MONGO_PORT=27019

but to no avail unfortunately. Is there something I am doing wrong?

Thanks in advance for your help.

Answer 1

I found the solution myself. What I was doing wrong is that the IoT Agent should be NOT be connected with a Sharded MongoDB as it only expects one Mongo instance. That instance is used to persist and retrieve IoT device created when you provision a sensor via the IoT Agent. Device measurement are sent to the Orion Context Broket which will persist into the Sharded MongoDB. Hope it can help somebody else.