No shards?

[richmondwang]

Just reading on the documentation, It seems that there are no shards added after completing the instructions.

--- Sharding Status --- 
  sharding version: {
	"_id" : 1,
	"minCompatibleVersion" : 5,
	"currentVersion" : 6,
	"clusterId" : ObjectId("587d306454828b89adaca524")
}
  shards:
  active mongoses:
	"3.4.1" : 1
  balancer:
	Currently enabled:  yes
	Currently running:  yes
		Balancer lock taken at Mon Jan 16 2017 22:18:53 GMT+0100 by ConfigServer:Balancer
	Failed balancer rounds in last 5 attempts:  0
	Migration Results for the last 24 hours: 
		No recent migrations
  databases:

Isn't the line shards: supposed to contain the added shards?
Is this setup include automatic adding of shards?

[senssei]

Thanks for asking. Yes, that is true. In this docker-compose there is no shards defined, only configuration for single logical shard instance on 3 nodes.

To create sample shard on it please follow instructions from https://warzycha.pl/mongo-db-shards-by-location/.

Afterwards you should get something like this:

--- Sharding Status --- 
  sharding version: {
    "_id" : 1,
    "minCompatibleVersion" : 5,
    "currentVersion" : 6,
    "clusterId" : ObjectId("58a1bfb6b0ad6efb4f160875")
}
  shards:
    {  "_id" : "rs1",  "host" : "rs1/172.18.0.10:27017,172.18.0.4:27017,172.18.0.5:27017",  "state" : 1,  "tags" : [ "US" ] }
    {  "_id" : "rs2",  "host" : "rs2/172.18.0.3:27017,172.18.0.7:27017,172.18.0.8:27017",  "state" : 1,  "tags" : [ "EU" ] }
  active mongoses:
    "3.4.1" : 1
  balancer:
    Currently enabled:  yes
    Currently running:  yes
        Balancer lock taken at Mon Feb 13 2017 15:16:28 GMT+0100 (Central Europe Standard Time) by ConfigServer:Balancer
    Failed balancer rounds in last 5 attempts:  0
    Migration Results for the last 24 hours: 
        1 : Success
  databases:
    {  "_id" : "test",  "primary" : "rs1",  "partitioned" : true }
        test.sample
            shard key: { "location" : 1, "_id" : 1 }
            unique: false
            balancing: true
            chunks:
                rs1 4
                rs2 1
            { "location" : { "$minKey" : 1 }, "_id" : { "$minKey" : 1 } } -->> { "location" : "EU", "_id" : { "$minKey" : 1 } } on : rs1 Timestamp(2, 1) 
            { "location" : "EU", "_id" : { "$minKey" : 1 } } -->> { "location" : "EU", "_id" : { "$maxKey" : 1 } } on : rs2 Timestamp(2, 0) 
            { "location" : "EU", "_id" : { "$maxKey" : 1 } } -->> { "location" : "US", "_id" : { "$minKey" : 1 } } on : rs1 Timestamp(1, 3) 
            { "location" : "US", "_id" : { "$minKey" : 1 } } -->> { "location" : "US", "_id" : { "$maxKey" : 1 } } on : rs1 Timestamp(1, 4) 
            { "location" : "US", "_id" : { "$maxKey" : 1 } } -->> { "location" : { "$maxKey" : 1 }, "_id" : { "$maxKey" : 1 } } on : rs1 Timestamp(1, 5) 
             tag: EU  { "location" : "EU", "_id" : { "$minKey" : 1 } } -->> { "location" : "EU", "_id" : { "$maxKey" : 1 } }
             tag: US  { "location" : "US", "_id" : { "$minKey" : 1 } } -->> { "location" : "US", "_id" : { "$maxKey" : 1 } }

[senssei]

Moreover, I think it could be done as additional shell commands in mongo-cluster-docker/scripts/init-shard.sh.

I did not put any shard configuration in it to provide generic environment for configuring any shard example - not only based on location as in my example.

You can read more here:

• https://docs.mongodb.com/manual/tutorial/sharding-tiered-hardware-for-varying-slas/
• https://docs.mongodb.com/manual/tutorial/sharding-segmenting-shards/

[senssei]

@richmondwang If my answer is ok with you I will close this issue and create a separate one for the enhancement.

[richmondwang]

@senssei Yes, you can close this.. thank you! :)