mongodb - YAML provided on official Mongo Docker Image page doesn't work on CentOS

Question

the given yml (which is originally provided here):

# Use root/example as user/password credentials
version: '3.1'

services:

  mongo:
    image: mongo
    restart: always
    environment:
      MONGO_INITDB_ROOT_USERNAME: root
      MONGO_INITDB_ROOT_PASSWORD: example

  mongo-express:
    image: mongo-express
    restart: always
    ports:
      - 8081:8081
    environment:
      ME_CONFIG_MONGODB_ADMINUSERNAME: root
      ME_CONFIG_MONGODB_ADMINPASSWORD: example

does work in my windows and macOS docker environments properly. But when I run the same yml in a CentOS docker environment mongo express just can't manage to connect to the mongodb service. Hence mongo express doesn't show up in the browser at localhost:8081. How can I fix this?

EDIT:

I suppose there seems to be an issue with DNS when it comes to the mapping of "mongo" to the respective container ip address. I can't explain why, since this is not an issue on windows.

this is the log of the mongo (mongodb) service:

{"t":{"$date":"2021-01-01T00:15:56.059+00:00"},"s":"I",  "c":"CONTROL",  "id":23285,   "ctx":"main","msg":"Automatically disabling TLS 1.0, to force-enable TLS 1.0 specify --sslDisabledProtocols 'none'"}
{"t":{"$date":"2021-01-01T00:15:56.063+00:00"},"s":"W",  "c":"ASIO",     "id":22601,   "ctx":"main","msg":"No TransportLayer configured during NetworkInterface startup"}
{"t":{"$date":"2021-01-01T00:15:56.063+00:00"},"s":"I",  "c":"NETWORK",  "id":4648601, "ctx":"main","msg":"Implicit TCP FastOpen unavailable. If TCP FastOpen is required, set tcpFastOpenServer, tcpFastOpenClient, and tcpFastOpenQueueSize."}
killing process with pid: 29
{"t":{"$date":"2021-01-01T00:15:56.063+00:00"},"s":"I",  "c":"CONTROL",  "id":23377,   "ctx":"SignalHandler","msg":"Received signal","attr":{"signal":15,"error":"Terminated"}}
{"t":{"$date":"2021-01-01T00:15:56.063+00:00"},"s":"I",  "c":"CONTROL",  "id":23378,   "ctx":"SignalHandler","msg":"Signal was sent by kill(2)","attr":{"pid":83,"uid":999}}
{"t":{"$date":"2021-01-01T00:15:56.063+00:00"},"s":"I",  "c":"CONTROL",  "id":23381,   "ctx":"SignalHandler","msg":"will terminate after current cmd ends"}
{"t":{"$date":"2021-01-01T00:15:56.063+00:00"},"s":"I",  "c":"REPL",     "id":4784900, "ctx":"SignalHandler","msg":"Stepping down the ReplicationCoordinator for shutdown","attr":{"waitTimeMillis":10000}}
{"t":{"$date":"2021-01-01T00:15:56.064+00:00"},"s":"I",  "c":"COMMAND",  "id":4784901, "ctx":"SignalHandler","msg":"Shutting down the MirrorMaestro"}
{"t":{"$date":"2021-01-01T00:15:56.064+00:00"},"s":"I",  "c":"SHARDING", "id":4784902, "ctx":"SignalHandler","msg":"Shutting down the WaitForMajorityService"}
{"t":{"$date":"2021-01-01T00:15:56.064+00:00"},"s":"I",  "c":"CONTROL",  "id":4784903, "ctx":"SignalHandler","msg":"Shutting down the LogicalSessionCache"}
{"t":{"$date":"2021-01-01T00:15:56.064+00:00"},"s":"I",  "c":"NETWORK",  "id":20562,   "ctx":"SignalHandler","msg":"Shutdown: going to close listening sockets"}
{"t":{"$date":"2021-01-01T00:15:56.064+00:00"},"s":"I",  "c":"NETWORK",  "id":23017,   "ctx":"listener","msg":"removing socket file","attr":{"path":"/tmp/mongodb-27017.sock"}}
{"t":{"$date":"2021-01-01T00:15:56.064+00:00"},"s":"I",  "c":"NETWORK",  "id":4784905, "ctx":"SignalHandler","msg":"Shutting down the global connection pool"}
{"t":{"$date":"2021-01-01T00:15:56.064+00:00"},"s":"I",  "c":"STORAGE",  "id":4784906, "ctx":"SignalHandler","msg":"Shutting down the FlowControlTicketholder"}
{"t":{"$date":"2021-01-01T00:15:56.064+00:00"},"s":"I",  "c":"-",        "id":20520,   "ctx":"SignalHandler","msg":"Stopping further Flow Control ticket acquisitions."}
{"t":{"$date":"2021-01-01T00:15:56.064+00:00"},"s":"I",  "c":"STORAGE",  "id":4784908, "ctx":"SignalHandler","msg":"Shutting down the PeriodicThreadToAbortExpiredTransactions"}
{"t":{"$date":"2021-01-01T00:15:56.064+00:00"},"s":"I",  "c":"STORAGE",  "id":4784934, "ctx":"SignalHandler","msg":"Shutting down the PeriodicThreadToDecreaseSnapshotHistoryCachePressure"}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"REPL",     "id":4784909, "ctx":"SignalHandler","msg":"Shutting down the ReplicationCoordinator"}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"SHARDING", "id":4784910, "ctx":"SignalHandler","msg":"Shutting down the ShardingInitializationMongoD"}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"REPL",     "id":4784911, "ctx":"SignalHandler","msg":"Enqueuing the ReplicationStateTransitionLock for shutdown"}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"-",        "id":4784912, "ctx":"SignalHandler","msg":"Killing all operations for shutdown"}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"-",        "id":4695300, "ctx":"SignalHandler","msg":"Interrupted all currently running operations","attr":{"opsKilled":3}}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"COMMAND",  "id":4784913, "ctx":"SignalHandler","msg":"Shutting down all open transactions"}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"REPL",     "id":4784914, "ctx":"SignalHandler","msg":"Acquiring the ReplicationStateTransitionLock for shutdown"}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"INDEX",    "id":4784915, "ctx":"SignalHandler","msg":"Shutting down the IndexBuildsCoordinator"}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"REPL",     "id":4784916, "ctx":"SignalHandler","msg":"Reacquiring the ReplicationStateTransitionLock for shutdown"}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"REPL",     "id":4784917, "ctx":"SignalHandler","msg":"Attempting to mark clean shutdown"}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"NETWORK",  "id":4784918, "ctx":"SignalHandler","msg":"Shutting down the ReplicaSetMonitor"}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"SHARDING", "id":4784921, "ctx":"SignalHandler","msg":"Shutting down the MigrationUtilExecutor"}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"CONTROL",  "id":4784925, "ctx":"SignalHandler","msg":"Shutting down free monitoring"}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"CONTROL",  "id":20609,   "ctx":"SignalHandler","msg":"Shutting down free monitoring"}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"FTDC",     "id":4784926, "ctx":"SignalHandler","msg":"Shutting down full-time data capture"}
{"t":{"$date":"2021-01-01T00:15:56.065+00:00"},"s":"I",  "c":"FTDC",     "id":20626,   "ctx":"SignalHandler","msg":"Shutting down full-time diagnostic data capture"}
{"t":{"$date":"2021-01-01T00:15:56.067+00:00"},"s":"I",  "c":"STORAGE",  "id":4784927, "ctx":"SignalHandler","msg":"Shutting down the HealthLog"}
{"t":{"$date":"2021-01-01T00:15:56.067+00:00"},"s":"I",  "c":"STORAGE",  "id":4784929, "ctx":"SignalHandler","msg":"Acquiring the global lock for shutdown"}
{"t":{"$date":"2021-01-01T00:15:56.067+00:00"},"s":"I",  "c":"STORAGE",  "id":4784930, "ctx":"SignalHandler","msg":"Shutting down the storage engine"}
{"t":{"$date":"2021-01-01T00:15:56.067+00:00"},"s":"I",  "c":"STORAGE",  "id":20282,   "ctx":"SignalHandler","msg":"Deregis

Answer 1

Try this:

# Use root/example as user/password credentials
version: '3.1'

services:

  mongo:
    image: mongo
    container_name: mongo
    restart: always
    environment:
      MONGO_INITDB_ROOT_USERNAME: root
      MONGO_INITDB_ROOT_PASSWORD: example
    ports:
      - 27017:27017

  mongo-express:
    image: mongo-express
    restart: always
    ports:
      - 8081:8081
    environment:
      ME_CONFIG_MONGODB_ADMINUSERNAME: root
      ME_CONFIG_MONGODB_ADMINPASSWORD: example
    links:
      - "mongo"
    depends_on:
      - "mongo"