MongoDB: Replication+Sharding

The most complicated setup are sharded replica sets. Let's assume we call our MongoDB cluster "webscale1", and want to deploy two shards, "shard1" and "shard2".

We would then assign the following roles and attributes to the nodes:

webscale1_mongos

{
    "name": "webscale1_mongos",
    "default_attributes": {
        "mongodb": {
            "cluster_name": "webscale1",
            "sharded_collections": {
                "webscale1.items": "name"
            }
        }
    },
    "override_attributes": { },
    "json_class": "Chef::Role",
    "description": "webscale1 MongoDB mongos",
    "chef_type": "role",
    "run_list": [
        "recipe[mongodb::mongos]"
    ]
}

webscale1_config_server

{
    "name": "webscale1_configserver",
    "default_attributes": {
        "mongodb": {
            "cluster_name": "webscale1"
        }
    },
    "override_attributes": { },
    "json_class": "Chef::Role",
    "description": "webscale1 MongoDB configserver",
    "chef_type": "role",
    "run_list": [
        "recipe[mongodb::configserver]"
    ]
}

webscale1_shard

{
    "name": "webscale1_shard",
    "default_attributes": {
        "mongodb": {
            "cluster_name": "webscale1"
        }
    },
    "override_attributes": { },
    "json_class": "Chef::Role",
    "description": "webscale1 MongoDB shard",
    "chef_type": "role",
    "run_list": [
        "recipe[mongodb::shard]",
        "recipe[mongodb::replicaset]"
    ]
}