MongoDB is a high-performance, open source, schema-free document-oriented data store that's easy to deploy, manage and use. It's network accessible, written in C++ and offers the following features:
- Collection oriented storage - easy storage of object-style data
- Full index support, including on inner objects
- Query profiling
- Replication and fail-over support
- Efficient storage of binary data including large objects (e.g. videos)
- Auto-sharding for cloud-level scalability (Q209) High performance, scalability, and reasonable depth of functionality are the goals for the project. This is a metapackage that depends on all the mongodb parts.
The MongoDB charm allows for certain values to be configurable via the config.yaml file.
A sample of the default settings of the config.yaml file at the time of writing are as follows:
options:
dbpath:
default: "/var/lib/mongodb"
type: string
description: The path where the data files will be kept.
logpath:
default: "/var/log/mongodb/mongodb.log"
type: string
description: The path where to send log data.
logappend:
default: True
type: boolean
description: Append log entries to existing log file
bind_ip:
default: "all"
type: string
description: IP address that mongodb should listen for connections.
port:
default: 27017
type: int
description: Default MongoDB port
journal:
default: True
type: boolean
description: Enable journaling, http://www.mongodb.org/display/DOCS/Journaling
cpu:
default: False
type: boolean
description: Enables periodic logging of CPU utilization and I/O wait
auth:
default: False
type: boolean
description: Turn on/off security
verbose:
default: False
type: boolean
description: Verbose logging output
objcheck:
default: False
type: boolean
description: Inspect all client data for validity on receipt (useful for developing drivers)
quota:
default: False
type: boolean
description: Enable db quota management
diaglog:
default: 0
type: int
description: Set oplogging level where n is 0=off (default), 1=W, 2=R, 3=both, 7=W+some reads
nocursors:
default: False
type: boolean
description: Diagnostic/debugging option
nohints:
default: False
type: boolean
description: Ignore query hints
noscripting:
default: False
type: boolean
description: Turns off server-side scripting. This will result in greatly limited functionality
notablescan:
default: False
type: boolean
description: Turns off table scans. Any query that would do a table scan fails
noprealloc:
default: False
type: boolean
description: Disable data file preallocation
nssize:
default: "default"
type: string
description: Specify .ns file size for new databases
mms-token:
default: "disabled"
type: string
description: Accout token for Mongo monitoring server
mms-name:
default: "disabled"
type: string
description: Server name for Mongo monitoring server
mms-interval:
default: "disabled"
type: string
description: Ping interval for Mongo monitoring server ( in number of seconds )
autoresync:
default: False
type: boolean
description: Automatically resync if slave data is stale
oplogSize:
default: "default"
type: string
description: Custom size for replication operation log
opIdMem:
default: "default"
type: string
description: Size limit for in-memory storage of op ids
replicaset:
default: myset
type: string
description: Name of the replica set
web_admin_ui:
default: True
type: boolean
description: Replica Set Admin UI ( accessible via default_port + 1000 )
replicaset_master:
default: auto
type: string
description: Replica Set master ( optional ). Possible values are 'auto' for automatic detection based on install time or 'host:port' to connect to 'host' on 'port' and register as a member.
master:
default: "self"
type: string
description: Who is the master DB. If not "self", put the Master DB here as "host:port"
config_server_port:
default: 27019
type: int
description: Port number to use for the config-server
config_server_dbpath:
default: "/mnt/var/lib/mongodb/configsvr"
type: string
description: The path where the config server data files will be kept.
config_server_logpath:
default: "/mnt/var/log/mongodb/configsvr.log"
type: string
description: The path where to send config server log data.
arbiter:
default: "disabled"
type: string
description: Enable arbiter mode. Possible values are 'disabled' for no arbiter, 'enable' to become an arbiter or 'host:port' to declare another host as an arbiter. replicaset_master must be set for this option to work.
mongos_logpath:
default: "/mnt/var/log/mongodb/mongos.log"
type: string
description: The path where to send log data from the mongo router.
mongos_port:
default: 27021
type: int
description: Port number to use for the mongo router
extra_config_options:
default: "none"
type: string
description: Extra options ( comma separated ) to be included ( at the end ) in the mongodb.conf file.
extra_daemon_options:
default: "none"
type: string
description: Extra options ( exactly as you would type them in the command line ) to be added via the command line to the mongodb daemon
backups_enabled:
default: False
type: boolean
description: Enable daily backups to disk.
backup_directory:
default: "/home/ubuntu/backups"
type: string
description: Where can the backups be found.
backup_copies_kept:
default: 7
type: int
description: Number of backups to keep. Keeps one week's worth by default.
-
replicaset
- ie: myreplicaset
- Each replicaset has a unique name to distinguish it’s members from other replicasets available in the network.
- The default value of myset should be fine for most single cluster scenarios.
-
web_admin_ui
- MongoDB comes with a basic but very informative web user interface that provides health and status information on the database node as well as the cluster.
- The default value of yes will start the Admin web UI on port 28017.
-
replicaset_master
- If this node is going to be joining an existing replicaset, you can specify a member of that cluster ( preferably the master node ) so we can join the existing replicaset.
- The value should be in the form of host[:port]
- ie: hostname ( will connect to hostname on the default port of 27017 )
- ie: hostname:port ( will connect to hostname on port number )
Most of the options in config.yaml have been modeled after the default configuration file for mongodb (normally in /etc/mongodb.conf) and should be familiar to most mongodb admins. Each option in this charm have a brief description of what it does.
Deploy the first MongoDB instance
juju deploy mongodb
juju expose mongodb
Deploy the first MongoDB instance
juju deploy mongodb
juju expose mongodb
Your deployment should look similar to this ( juju status ):
machines:
0:
dns-name: ec2-50-19-46-207.compute-1.amazonaws.com
instance-id: i-3817fc5a
instance-state: running
state: running
1:
dns-name: ec2-50-17-73-255.compute-1.amazonaws.com
instance-id: i-90c822f2
instance-state: running
state: running
services:
mongodb:
charm: local:oneiric/mongodb-17
exposed: true
relations:
replica-set: mongodb
units:
mongodb/0:
machine: 1
open-ports:
- 27017/tcp
- 28017/tcp
public-address: ec2-50-17-73-255.compute-1.amazonaws.com
relations:
replica-set:
state: up
state: started
In addition, the MongoDB web interface should also be accessible via the services’ public-address and port 28017 ( ie: http://ec2-50-17-73-255.compute-1.amazonaws.com:28017 ).
juju set mongodb replicaset=<new_replicaset_name>
juju add-unit mongodb
juju add-unit mongodb -n5
We now have a working MongoDB replica-set.
According the the mongodb documentation found on their website (http://docs.mongodb.org/manual/tutorial/deploy-shard-cluster/), one way of deploying a Shard Cluster is as follows:
- deploy config servers
- deploy a mongo shell (mongos)
- deploy shards
- connect the config servers to the mongo shell
- add the shards to the mongo shell
Using Juju we can deploy a sharded cluster using the following commands:
shard1:
replicaset: shard1
shard2:
replicaset: shard2
shard3:
replicaset: shard3
configsvr:
replicaset: configsvr
We'll save this one as ~/mongodb-shard.yaml
juju bootstrap
juju deploy mongodb configsvr --config ~/mongodb-shard.yaml -n3
juju deploy mongodb mongos
juju deploy mongodb shard1 --config ~/mongodb-shard.yaml -n3
juju deploy mongodb shard2 --config ~/mongodb-shard.yaml -n3
juju deploy mongodb shard3 --config ~/mongodb-shard.yaml -n3
juju add-relation mongos:mongos-cfg configsvr:configsvr
juju add-realtion mongos:mongos shard1:database
juju add-realtion mongos:mongos shard2:database
juju add-realtion mongos:mongos shard3:database
With the above commands, we should now have a three replica-set sharded cluster running. Using the default configuration, here are some details of our sharded cluster:
- mongos is running on port 27021
- configsvr is running on port 27019
- the shards are running on the default mongodb port of 27017
- The web admin is turned on by default and accessible with your browser on port 28017 on each of the shards.
To verify that your sharded cluster is running, connect to the mongo shell and run sh.status():
- mongo --host <mongos_host>:<mongos_port>
- run sh.status() You should see your the hosts for your shards in the status output.
To deploy mongodb using permanent volume on Openstack, the permanent volume should be attached to the mongodb unit just after the deployment, then the configuration should be updated like follows.
juju set mongodb volume-dev-regexp="/dev/vdc" volume-map='{"mongodb/0": "vol-id-00000000000000"}' volume-ephemeral-storage=false
Backups can be enabled via config. Note that destroying the service cannot currently remove the backup cron job so it will continue to run. There is a setting for the number of backups to keep, however, to prevent from filling disk space.
To fetch the backups scp the files down from the path in the config.
- If your master/slave/replicaset deployment is not updating correctly, check the log files at /var/log/mongodb/mongodb.log to see if there is an obvious reason ( port not open etc.).
- Ensure that TCP port 27017 is accessible from all of the nodes in the deployment.
- If you are trying to access your MongoDB instance from outside your deployment, ensure that the service has been exposed ( juju expose mongodb )
- Make sure that the mongod process is running ( ps -ef | grep mongo ).
- Try restarting the database ( restart mongodb )
- If all else fails, remove the data directory on the slave ( rm -fr /var/log/mongodb/data/* ) and restart the mongodb-slave daemon ( restart mongodb ).
- The MongoDB website ( http://www.mongodb.org ) has a very good documentation section ( http://www.mongodb.org/display/DOCS/Home )