Installs and configures various kind of MongoDB setups, including sharding and replication.

The cookbook aims to be platform independant, but is best tested on debian squeeze systems.

This cookbook contains a definition mongodb_instance which can be used to configure a certain type of mongodb instance, like the default mongodb or various components of a sharded setup.

For examples see the USAGE section below.

• mongodb[:dbpath] - Location for mongodb data directory, defaults to "/var/lib/mongodb"
• mongodb[:logpath] - Path for the logfiles, default is "/var/log/mongodb"
• mongodb[:port] - Port the mongod listens on, default is 27017
• mongodb[:client_role] - Role identifing all external clients which should have access to a mongod instance
• mongodb[:cluster_role_prefix] - Name prefix for all roles used to identify all members of a mongodb cluster.
• mongodb[:shard_name] - Name of a shard, default is "default"
• mongodb[:sharded_collections] - Define which collections are sharded

To install and run a single mongodb instance, simply add

include_recipe "mongodb::default"

to your recipe. This will run the mongodb instance as configured by your distribution. By changing the dbpath, logpath and port settings (see ATTRIBUTES) for this node you will be able to change this defaults. If you would like to tweak more settings, simply use the mongodb_instance definition, like

mongodb_instance "mongodb" do
  port node['application']['port']
end

This definition also allows you to run another mongod instance with a different name on the same node

mongodb_instance "my_instance" do
  port node['mongodb']['port'] + 100
  dbpath "/data/"
end

The result is a new system service with

  /etc/init.d/my_instance <start|stop|restart|status>

If you would like to add your mongodb instance to a replicaset all you have to do is adding mongodb::replicaset to the node's run_list and make sure to add one or more roles with the same prefix to all members of the replicaset. This prefix has to be defined in mongodb[:cluster_role_prefix] . For example you could create a role called "my_replicaset" and add this role to the run_list of all nodes which should be in the replicaset. Finally you only have to define mongodb[:cluster_role_prefix] for all nodes in this cluster. This way they are able to find each other.

Configure sharding is a bit more complicated, because you need a few more components, but the idea is the same: identification of the members with their different internal roles (mongos, configserver, etc.) is done via mongodb[:cluster_role_prefix] and a mongodb[:shard_name]

Let's have a look at a simple sharding setup, consisting of two shard servers, one config server and one mongos.

First we would like to configure the two shards. For doing so, just use mongodb::shard in the node's run_list and define a unique mongodb[:shard_name] for each of these two nodes, say "shard1" and "shard2".

Then configure a node to act as a config server - by using the mongodb::configserver recipe.

And finally you need to configure the mongos. This can be done by using the mongodb::mongos recipe. The mongos needs some special configuration, as these mongos are actually doing the configuration of the whole sharded cluster. Most importantly you need to define a set of mongodb[:sharded_collections] The value of this attribute should look like

{
  "test.addressbook": "name",
  "mydatabase.calendar": "date"
}

Now mongos will automatically enable sharding for the "test" and the "mydatabase" database. Also the "addressbook" and the "calendar" collection will be sharded, with sharding key "name" resp. "date". In the context of a sharding cluster always keep in mind to use roles with the same prefix, and define this prefix, to identify all members. Also shard names are important to distinguish the different shards.

This is esp. important when you want to replicate shards. The setup is not much different to the one described above. All you have to do is adding the mongodb::replicaset recipe to all shard nodes, and make sure that all shard nodes which should be in the same replicaset have the same shard name.

Author:: Markus Korn [email protected]

Copyright:: 2011, edelight GmbH

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http:https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.