Demo Mongo Sharded Cluster with Docker Compose
PSS Style (Primary -Secondary - Secondary)
Need PSA? Check here
WARNING (Windows & OS X)
The default Docker setup on Windows and OS X uses a VirtualBox VM to host the Docker daemon. Unfortunately, the mechanism VirtualBox uses to share folders between the host system and the Docker container is not compatible with the memory mapped files used by MongoDB (see vbox bug, docs.mongodb.org and related jira.mongodb.org bug). This means that it is not possible to run a MongoDB container with the data directory mapped to the host.
– Docker Hub (source here or here)
Mongo Components
- Config Server (3 member replica set):
configsvr01,configsvr02,configsvr03 - 3 Shards (each a 3 member
PSSreplica set):shard01-a,shard01-b,shard01-cshard02-a,shard02-b,shard02-cshard03-a,shard03-b,shard03-c
- 2 Routers (mongos):
router01,router02
Setup
- Step 1: Start all of the containers
docker-compose up -dIf you get error "docker.errors.DockerException: Error while fetching server API version" and used WSL (Windows Subsystem for Linux) need to enable 'WSL Integration' for required distro in Windows Docker Desktop (Settings -> Resources-> WSL Integration -> Enable integration with required distros).
Link: https://stackoverflow.com/a/65347214/3007147
- Step 2: Initialize the replica sets (config servers and shards) and routers
docker-compose exec configsvr01 sh -c "mongo < /scripts/init-configserver.js"
docker-compose exec shard01-a sh -c "mongo < /scripts/init-shard01.js"
docker-compose exec shard02-a sh -c "mongo < /scripts/init-shard02.js"
docker-compose exec shard03-a sh -c "mongo < /scripts/init-shard03.js"If you get error like "E QUERY [thread1] SyntaxError: unterminated string literal @(shellhelp2)", problem maybe due to:
On Unix, you will get this error if your script has Dos/Windows end of lines (CRLF) instead of Unix end of lines (LF).
To fix it, modify script files in scripts folder, remove newline, change multi line to one line
Link: https://stackoverflow.com/a/51728442/3007147
- Step 3: Initializing the router
Note: Wait a bit for the config server and shards to elect their primaries before initializing the router
docker-compose exec router01 sh -c "mongo < /scripts/init-router.js"- Step 4: Enable sharding and setup sharding-key
docker-compose exec router01 mongo --port 27017
// Enable sharding for database `MyDatabase`
sh.enableSharding("MyDatabase")
// Setup shardingKey for collection `MyCollection`**
db.adminCommand( { shardCollection: "MyDatabase.MyCollection", key: { supplierId: "hashed" } } )
Done! but before you start inserting data you should verify them first
Verify
- Verify the status of the sharded cluster
docker-compose exec router01 mongo --port 27017
sh.status()Sample Result:
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("5d38fb010eac1e03397c355a")
}
shards:
{ "_id" : "rs-shard-01", "host" : "rs-shard-01/shard01-a:27017,shard01-b:27017,shard01-c:27017", "state" : 1 }
{ "_id" : "rs-shard-02", "host" : "rs-shard-02/shard02-a:27017,shard02-b:27017,shard02-c:27017", "state" : 1 }
{ "_id" : "rs-shard-03", "host" : "rs-shard-03/shard03-a:27017,shard03-b:27017,shard03-c:27017", "state" : 1 }
active mongoses:
"4.0.10" : 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 }
- Verify status of replica set for each shard
You should see 1 PRIMARY, 2 SECONDARY
docker exec -it rydell-shard-01-node-a bash -c "echo 'rs.status()' | mongo --port 27017"
docker exec -it rydell-shard-02-node-a bash -c "echo 'rs.status()' | mongo --port 27017"
docker exec -it rydell-shard-03-node-a bash -c "echo 'rs.status()' | mongo --port 27017" Sample Result:
MongoDB shell version v4.0.11
connecting to: mongodb://127.0.0.1:27017/?gssapiServiceName=mongodb
Implicit session: session { "id" : UUID("dcfe5d8f-75ef-45f7-9595-9d72dc8a81fc") }
MongoDB server version: 4.0.11
{
"set" : "rs-shard-01",
"date" : ISODate("2019-08-01T06:53:59.175Z"),
"myState" : 1,
"term" : NumberLong(1),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"heartbeatIntervalMillis" : NumberLong(2000),
"optimes" : {
"lastCommittedOpTime" : {
"ts" : Timestamp(1564642438, 1),
"t" : NumberLong(1)
},
"readConcernMajorityOpTime" : {
"ts" : Timestamp(1564642438, 1),
"t" : NumberLong(1)
},
"appliedOpTime" : {
"ts" : Timestamp(1564642438, 1),
"t" : NumberLong(1)
},
"durableOpTime" : {
"ts" : Timestamp(1564642438, 1),
"t" : NumberLong(1)
}
},
"lastStableCheckpointTimestamp" : Timestamp(1564642428, 1),
"members" : [
{
"_id" : 0,
"name" : "shard01-a:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 390,
"optime" : {
"ts" : Timestamp(1564642438, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2019-08-01T06:53:58Z"),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "",
"electionTime" : Timestamp(1564642306, 1),
"electionDate" : ISODate("2019-08-01T06:51:46Z"),
"configVersion" : 2,
"self" : true,
"lastHeartbeatMessage" : ""
},
{
"_id" : 1,
"name" : "shard01-b:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 142,
"optime" : {
"ts" : Timestamp(1564642428, 1),
"t" : NumberLong(1)
},
"optimeDurable" : {
"ts" : Timestamp(1564642428, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2019-08-01T06:53:48Z"),
"optimeDurableDate" : ISODate("2019-08-01T06:53:48Z"),
"lastHeartbeat" : ISODate("2019-08-01T06:53:57.953Z"),
"lastHeartbeatRecv" : ISODate("2019-08-01T06:53:57.967Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "shard01-a:27017",
"syncSourceHost" : "shard01-a:27017",
"syncSourceId" : 0,
"infoMessage" : "",
"configVersion" : 2
},
{
"_id" : 2,
"name" : "shard01-c:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 142,
"optime" : {
"ts" : Timestamp(1564642428, 1),
"t" : NumberLong(1)
},
"optimeDurable" : {
"ts" : Timestamp(1564642428, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2019-08-01T06:53:48Z"),
"optimeDurableDate" : ISODate("2019-08-01T06:53:48Z"),
"lastHeartbeat" : ISODate("2019-08-01T06:53:57.952Z"),
"lastHeartbeatRecv" : ISODate("2019-08-01T06:53:57.968Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "shard01-a:27017",
"syncSourceHost" : "shard01-a:27017",
"syncSourceId" : 0,
"infoMessage" : "",
"configVersion" : 2
}
],
"ok" : 1,
"operationTime" : Timestamp(1564642438, 1),
"$gleStats" : {
"lastOpTime" : Timestamp(0, 0),
"electionId" : ObjectId("7fffffff0000000000000001")
},
"lastCommittedOpTime" : Timestamp(1564642438, 1),
"$configServerState" : {
"opTime" : {
"ts" : Timestamp(1564642426, 2),
"t" : NumberLong(1)
}
},
"$clusterTime" : {
"clusterTime" : Timestamp(1564642438, 1),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
}
bye
- Check database status
docker-compose exec router01 mongo --port 27017
use MyDatabase
db.stats()
db.MyCollection.getShardDistribution()Sample Result:
{
"raw" : {
"rs-shard-01/shard01-a:27017,shard01-b:27017,shard01-c:27017" : {
"db" : "MyDatabase",
"collections" : 1,
"views" : 0,
"objects" : 0,
"avgObjSize" : 0,
"dataSize" : 0,
"storageSize" : 4096,
"numExtents" : 0,
"indexes" : 2,
"indexSize" : 8192,
"fsUsedSize" : 12439990272,
"fsTotalSize" : 62725787648,
"ok" : 1
},
"rs-shard-03/shard03-a:27017,shard03-b:27017,shard03-c:27017" : {
"db" : "MyDatabase",
"collections" : 1,
"views" : 0,
"objects" : 0,
"avgObjSize" : 0,
"dataSize" : 0,
"storageSize" : 4096,
"numExtents" : 0,
"indexes" : 2,
"indexSize" : 8192,
"fsUsedSize" : 12439994368,
"fsTotalSize" : 62725787648,
"ok" : 1
},
"rs-shard-02/shard02-a:27017,shard02-b:27017,shard02-c:27017" : {
"db" : "MyDatabase",
"collections" : 1,
"views" : 0,
"objects" : 0,
"avgObjSize" : 0,
"dataSize" : 0,
"storageSize" : 4096,
"numExtents" : 0,
"indexes" : 2,
"indexSize" : 8192,
"fsUsedSize" : 12439994368,
"fsTotalSize" : 62725787648,
"ok" : 1
}
},
"objects" : 0,
"avgObjSize" : 0,
"dataSize" : 0,
"storageSize" : 12288,
"numExtents" : 0,
"indexes" : 6,
"indexSize" : 24576,
"fileSize" : 0,
"extentFreeList" : {
"num" : 0,
"totalSize" : 0
},
"ok" : 1,
"operationTime" : Timestamp(1564004884, 36),
"$clusterTime" : {
"clusterTime" : Timestamp(1564004888, 1),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
}
More commands
docker exec -it rydell-mongo-config-01 bash -c "echo 'rs.status()' | mongo --port 27017"
docker exec -it rydell-shard-01-node-a bash -c "echo 'rs.help()' | mongo --port 27017"
docker exec -it rydell-shard-01-node-a bash -c "echo 'rs.status()' | mongo --port 27017"
docker exec -it rydell-shard-01-node-a bash -c "echo 'rs.printReplicationInfo()' | mongo --port 27017"
docker exec -it rydell-shard-01-node-a bash -c "echo 'rs.printSlaveReplicationInfo()' | mongo --port 27017"Normal Startup
The cluster only has to be initialized on the first run. Subsequent startup can be achieved simply with docker-compose up or docker-compose up -d
Resetting the Cluster
To remove all data and re-initialize the cluster, make sure the containers are stopped and then:
docker-compose rmClean up docker-compose
docker-compose down -v --rmi all --remove-orphansExecute the First Run instructions again.
Screenshot
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