configServer in sync_gateway.json for sync_gateway 2.1.0-121

os:ubuntu 16.04
cbs: 5.5.1
cbl: 2.0 android(v7.0)
sg: 2.1.0-121


  "logging": {
    "console": {
      "log_keys": ["*"]
  "configServer": "",
  "databases": {
    "db": {
      "server": "",
      "users": { "GUEST": { "disabled": false, "admin_channels": ["*"] } },
      "allow_conflicts": false,
      "revs_limit": 20

sg log as following:

2018-10-11T05:20:20.483Z [INF] Cache:     #10 ==> channel "*"
2018-10-11T05:26:29.294Z [ERR] No logFilePath configured, and --defaultLogFilePath flag is not set. Log files required for product support are not being generated. -- base
.(*LoggingConfig).Init() at logging_config.go:402018-10-11T05:26:29.294Z ==== Couchbase Sync Gateway/2.1.0(121;a036bd8) ====
2018-10-11T05:26:29.294Z [INF] Console LogKeys: [* HTTP]
2018-10-11T05:26:29.294Z [INF] Console LogLevel: info
2018-10-11T05:26:29.294Z [INF] Log Redaction Level: none
2018-10-11T05:26:29.294Z [INF] requestedSoftFDLimit < currentSoftFdLimit (5000 < 65536) no action needed
2018-10-11T05:26:29.294Z [INF] Opening db /db as bucket "default", pool "default", server <>
2018-10-11T05:26:29.294Z [INF] GoCBCustomSGTranscoder Opening Couchbase database default on <> as user "default"
2018-10-11T05:26:29.295Z [INF] Auth: Attempting credential authentication
ns_per_host=2562018-10-11T05:26:29.300Z [INF] Successfully opened bucket
2018-10-11T05:26:29.307Z [INF] Initializing indexes with numReplicas: 1...
2018-10-11T05:26:29.410Z [INF] Verifying index availability for bucket default...
2018-10-11T05:26:29.420Z [INF] Indexes ready for bucket default.
2018-10-11T05:26:29.421Z [INF] Cache: Initializing changes cache with options {ChannelCacheOptions:{ChannelCacheMinLength:0 ChannelCacheMaxLength:0 ChannelCacheAge:0s} Cac
hePendingSeqMaxWait:5s CachePendingSeqMaxNum:10000 CacheSkippedSeqMaxWait:1h0m0s}2018-10-11T05:26:29.421Z [INF] Initializing changes cache for database db with sequence: 10
2018-10-11T05:26:29.421Z [INF] DCP: Starting mutation feed on bucket default due to either channel cache mode or doc tracking (auto-import/bucketshadow)
2018-10-11T05:26:29.421Z [INF] DCP: Using DCP feed for bucket: "default" (based on feed_type specified in config file)
2018-10-11T05:26:29.501Z [INF] Using default sync function 'channel(doc.channels)' for database "db"
2018-10-11T05:26:29.501Z [WRN] QueryAccess called with empty username - returning empty result iterator -- db.(*DatabaseContext).QueryAccess() at query.go:239
2018-10-11T05:26:29.501Z [INF] Access: Computed channels for "": !:1,*:10
2018-10-11T05:26:29.501Z [WRN] QueryRoleAccess called with empty username -- db.(*DatabaseContext).QueryRoleAccess() at query.go:260
2018-10-11T05:26:29.501Z [INF] Access: Computed roles for "": 
2018-10-11T05:26:29.502Z [INF]     Reset guest user to config
2018-10-11T05:26:29.502Z [INF] Starting admin server on :4985
2018-10-11T05:26:29.510Z [INF] Starting server on :4984 ...
2018-10-11T05:26:29.514+00:00 [INFO] Using plain authentication for user <ud>default</ud> 

but for sg 1.4, the same configuration will work , log as following

2018-10-11T11:30:26.918+06:00 Enabling logging: [*]
2018-10-11T11:30:26.918+06:00 ==== Couchbase Sync Gateway/1.4.1(3;ddffd85) ====
2018-10-11T11:30:26.918+06:00 requestedSoftFDLimit >= currentHardFdLimit (5000 >= 4096) capping at 4096
2018-10-11T11:30:26.918+06:00 Configured process to allow 4096 open file descriptors
2018-10-11T11:30:26.918+06:00 Opening db /db as bucket "default", pool "default", server <http://localhost:8091>
2018-10-11T11:30:26.918+06:00 Opening Couchbase database default on <http://localhost:8091> as user "default"
_time=2018-10-11T11:30:26.936+06:00 _level=INFO _msg= Trying with selected node 0
_time=2018-10-11T11:30:26.936+06:00 _level=INFO _msg= Trying with
_time=2018-10-11T11:30:26.942+06:00 _level=INFO _msg=Got new configuration for bucket default
_time=2018-10-11T11:30:26.963+06:00 _level=INFO _msg= Trying with selected node 0
2018-10-11T11:30:27.002+06:00 Cache: Initializing changes cache with options {ChannelCacheOptions:{ChannelCacheMinLength:0 ChannelCacheMaxLength:0 ChannelCacheAge:0s} CachePendingSeqMaxWait:5s CachePendingSeqMaxNum:10000 CacheSkippedSeqMaxWait:1h0m0s}
2018-10-11T11:30:27.003+06:00 Feed: Using TAP feed for bucket: "default" (based on feed_type specified in config file
2018-10-11T11:30:27.008+06:00     Reset guest user to config
2018-10-11T11:30:27.008+06:00 WARNING: The GUEST user is the only user defined in the 'db' database, but is either disabled or has no access to any channels.  This means that you will not be able to get useful data out of the sync gateway over the standard port.  FIX: enable and/or grant access to the GUEST user to channels via the admin_channels parameter. -- rest.emitAccessRelatedWarnings() at server_context.go:897
2018-10-11T11:30:27.008+06:00 Starting admin server on
2018-10-11T11:30:27.014+06:00 Starting server on :4984 ...

and one more question: when configServer is configured, why should I add server in database?
as document mentioned


URL of a Couchbase database-configuration server (for dynamic database discovery). A database-configuration server allows Sync Gateway to load a database configuration dynamically from a remote endpoint. If a database configuration server is defined, when Sync Gateway gets a request for a database that it doesn't know about, then Sync Gateway will attempt to retrieve the database configuration properties from the URL ConfigServer/DBname, where DBname is the database name.

how should I configure DBname?

Have you looked over the Sync Gateway 2.1 release notes?

Look over the “Continuous Logging” section.

thank you for replying, but my question is how to configure configServer.

Please look at the sample config files in the examples folder . Your configServer will have to implement an URL endpoint that will return the database config.

when configServer is configured, How should I configure DBname ? should I need configure bucket and serverparameters?

Yes. Did you try using the sample config file and tweaking it for your setup? Also, can you specify your need for using configServer