Continuous admin.$cmd queries in slowest operations

Ops and Admin
1

Hello,

we are facing one strange issue in the Realtime Slowest operations. It seems that for every docker that connects to mongoDB we have one or more continuous admin.$cmd commands that are reading some thousands of documents.

All our dockers are NodeJS projects accessing the database via mongoose. One sample of the JSON RESPONSE is:

op: command
locks: Object
lockStats: Object
waitingForFlowControl: false
host: xxxx-shard-00-02-vckat.azure.mongodb.net:27017
microsecs_running: 8432221
currentOpTime: 2021-06-09T12:02:02.646+00:00
secs_running: 8
waitingForLock: false
flowControlStats: Object
type: op
active: true
opid: 34729718
ns: admin.$cmd
numYields: 0
waitingForLatch: Object
  timestamp: Object
    $date: 2021-06-09T12:01:54.314Z
  captureName: FutureResolution
connectionId: 55945
clientMetadata: Object
  driver: Object
    name: nodejs|Mongoose
    version: 3.6.6
  os: Object
    type: Linux
    name: linux
    architecture: x64
    version: 5.4.0-1032-azure
  platform: 'Node.js v10.15.3, LE (unified)
  version: 3.6.6|5.12.5
desc: conn55945
client: xx.xx.xx.xx:49380
query: Object
  $db: admin
  ismaster: true
  maxAwaitTimeMS: 10000
  topologyVersion: Object
    processId: Object
      $oid: 60bd2bb49561137ee56a1868
    counter: 8
$clusterTime: Object
  clusterTime: Object
    $timestamp: Object
      t: 1623235570
      i: 2
  signature: Object
    hash: Object
      $binary: Object
        base64: /YEfTf0O9ucqS31QdgoFKDLo0qg=
        subType: 00
    keyId: 6914106613016035000

We are using MongoDB version 4.4.6.

Do you have an idea on what type of activity the system is performing?

Thanks