Deploy Sharded Cluster with Keyfile Authentication
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Overview
Enforcing access control on a sharded cluster requires configuring:
Security between components of the cluster using Internal Authentication.
Security between connecting clients and the cluster using User Access Controls.
For this tutorial, each member of the sharded cluster must use the same
internal authentication mechanism and settings. This means enforcing internal
authentication on each mongos
and mongod
in the cluster.
The following tutorial uses a keyfile to enable internal authentication.
Enforcing internal authentication also enforces user access control. To
connect to the replica set, clients like the mongo
shell need to
use a user account. See
Access Control.
CloudManager and OpsManager
If you are using Cloud Manager or Ops Manager to manage your deployment, see the respective Cloud Manager manual or the Ops Manager manual to enforce authentication.
Considerations
Tip
When possible, use a logical DNS hostname instead of an ip address, particularly when configuring replica set members or sharded cluster members. The use of logical DNS hostnames avoids configuration changes due to ip address changes.
IP Binding
MongoDB binaries, mongod
and
mongos
, bind to localhost
by default.
Keyfile Security
Keyfiles are bare-minimum forms of security and are best suited for testing or development environments. For production environments we recommend using x.509 certificates.
Access Control
This tutorial covers creating the minimum number of administrative
users on the admin
database only. For the user authentication,
the tutorial uses the default SCRAM
authentication mechanism. Challenge-response security mechanisms are
best suited for testing or development environments. For production
environments, we recommend using x.509
certificates or LDAP Proxy Authentication
(available for MongoDB Enterprise only) or Kerberos Authentication
(available for MongoDB Enterprise only).
For details on creating users for specific authentication mechanism, refer to the specific authentication mechanism pages.
See ➤ Configure Role-Based Access Control for best practices for user creation and management.
Users
In general, to create users for a sharded clusters, connect to the
mongos
and add the sharded cluster users.
However, some maintenance operations require direct connections to specific shards in a sharded cluster. To perform these operations, you must connect directly to the shard and authenticate as a shard-local administrative user.
Shard-local users exist only in the specific shard and should only be
used for shard-specific maintenance and configuration. You cannot
connect to the mongos
with shard-local users.
This tutorial requires creating sharded cluster users, but includes optional steps for adding shard-local users.
See the Users security documentation for more information.
Operating System
This tutorial uses the mongod
and mongos
programs. Windows users should use the mongod.exe
and
mongos.exe
programs instead.
Deploy Sharded Cluster with Keyfile Access Control
The following procedures involve creating a new sharded cluster that consists
of a mongos
, the config servers, and two shards.
Tip
When possible, use a logical DNS hostname instead of an ip address, particularly when configuring replica set members or sharded cluster members. The use of logical DNS hostnames avoids configuration changes due to ip address changes.
Create the Keyfile
With keyfile authentication, each
mongod
or mongos
instances in the sharded cluster uses the contents of the keyfile as the
shared password for authenticating other members in the deployment. Only
mongod
or mongos
instances with the correct keyfile can join the sharded cluster.
Note
Starting in MongoDB 4.2, keyfiles for internal membership authentication use YAML format to allow for multiple keys in a keyfile. The YAML format accepts either:
A single key string (same as in earlier versions)
A sequence of key strings
The YAML format is compatible with the existing single-key keyfiles that use the text file format.
A key's length must be between 6 and 1024 characters and may only contain characters in the base64 set. All members of the sharded cluster must share at least one common key.
Note
On UNIX systems, the keyfile must not have group or world permissions. On Windows systems, keyfile permissions are not checked.
You can generate a keyfile using any method you choose. For example,
the following operation uses openssl
to generate a complex
pseudo-random 1024 character string to use as a shared password. It then
uses chmod
to change file permissions to provide read
permissions for the file owner only:
openssl rand -base64 756 > <path-to-keyfile> chmod 400 <path-to-keyfile>
See Keyfiles for additional details and requirements for using keyfiles.
Distribute the Keyfile
Copy the keyfile to each server hosting the sharded cluster members.
Ensure that the user running the mongod
or mongos
instances is the owner of the
file and can access the keyfile.
Avoid storing the keyfile on storage mediums that can be easily
disconnected from the hardware hosting the mongod
or mongos
instances, such as a
USB drive or a network attached storage device.
Create the Config Server Replica Set
The following steps deploys a config server replica set.
For a production deployment, deploys a config server replica set with at least three members. For testing purposes, you can create a single-member replica set.
Start each mongod
in the config server replica set.
Include the keyFile
setting. The keyFile
setting
enforces both Internal/Membership Authentication and
Role-Based Access Control.
You can specify the mongod
settings either via a
configuration file or the command line.
Configuration File
If using a configuration file, set security.keyFile
to the
keyfile's path, sharding.clusterRole
to configsvr
,
and replication.replSetName
to the desired name of the
config server replica set.
security: keyFile: <path-to-keyfile> sharding: clusterRole: configsvr replication: replSetName: <setname>
Include additional options as required
for your configuration. For instance, if you wish remote clients to
connect to your deployment or your deployment members are run on
different hosts, specify the net.bindIp
setting. For more
information, see Localhost Binding Compatibility Changes.
Start the mongod
specifying the --config
option and the
path to the configuration file.
mongod --config <path-to-config-file>
Command Line
If using the command line parameters, start the mongod
with
the --keyFile
, --configsvr
, and --replSet
parameters.
mongod --keyFile <path-to-keyfile> --configsvr --replSet <setname> --dbpath <path>
Include additional options as required for your configuration. For
instance, if you wish remote clients to connect to your deployment
or your deployment members are run on different hosts, specify the
--bind_ip
. For more information, see
Localhost Binding Compatibility Changes.
Connect to a member of the replica set over the localhost interface.
Connect a mongo
shell to one of the
mongod
instances over the localhost
interface. You must run the mongo
shell on the same physical machine as the mongod
instance.
The localhost interface is only available since no users have been created for the deployment. The localhost interface closes after the creation of the first user.
The rs.initiate()
method initiates the replica set and can
take an optional replica set configuration document. In the replica set
configuration document, include:
The
_id
. The_id
must match the--replSet
parameter passed to themongod
.The
members
field. Themembers
field is an array and requires a document per each member of the replica set.The
configsvr
field. Theconfigsvr
field must be set totrue
for the config server replica set.
See Replica Set Configuration for more information on replica set configuration documents.
Initiate the replica set using the rs.initiate()
method
and a configuration document:
rs.initiate( { _id: "myReplSet", configsvr: true, members: [ { _id : 0, host : "cfg1.example.net:27019" }, { _id : 1, host : "cfg2.example.net:27019" }, { _id : 2, host : "cfg3.example.net:27019" } ] } )
Note
To use the config server replica set (CSRS) in this procedure, you must first wait
until it completes its initialization. If the CSRS has not initialized, it causes
NotYetInitialized
errors.
Once the config server replica set (CSRS) is initiated and up, proceed to creating the shard replica sets.
Create the Shard Replica Sets
For a production deployment, use a replica set with at least three members. For testing purposes, you can create a single-member replica set.
These steps include optional procedures for adding shard-local users. Executing them now ensures that there are users available for each shard to perform shard-level maintenance.
Start each member of the replica set with access control enabled.
Running a mongod
with the keyFile
parameter enforces both
Internal/Membership Authentication and
Role-Based Access Control.
Start each mongod
in the replica set using either
a configuration file or the command line.
Configuration File
If using a configuration file, set the security.keyFile
option
to the keyfile's path, the replication.replSetName
to the
desired name of the replica set, and the sharding.clusterRole
option to shardsvr
.
security: keyFile: <path-to-keyfile> sharding: clusterRole: shardsvr replication: replSetName: <replSetName> storage: dbPath: <path>
Include additional options as required
for your configuration. For instance, if you wish remote clients to
connect to your deployment or your deployment members are run on
different hosts, specify the net.bindIp
setting. For more
information, see Localhost Binding Compatibility Changes.
Start the mongod
specifying the --config
option
and the path to the configuration file.
mongod --config <path-to-config-file>
Command Line
If using the command line option, when starting the component, specify
the --keyFile
, replSet
, and --shardsvr
parameters, as in the
following example:
mongod --keyFile <path-to-keyfile> --shardsvr --replSet <replSetName> --dbpath <path>
Include additional options as required for your configuration. For
instance, if you wish remote clients to connect to your deployment
or your deployment members are run on different hosts, specify the
--bind_ip
. For more information, see
Localhost Binding Compatibility Changes.
Connect to a member of the replica set over the localhost interface.
Connect a mongo
shell to one of the
mongod
instances over the localhost
interface. You must run the mongo
shell on the same physical machine as the mongod
instance.
The localhost interface is only available since no users have been created for the deployment. The localhost interface closes after the creation of the first user.
Initiate the replica set.
From the mongo
shell, run the rs.initiate()
method.
rs.initiate()
can take an optional replica set
configuration document. In the
replica set configuration document, include:
The
_id
field set to the replica set name specified in either thereplication.replSetName
or the--replSet
option.The
members
array with a document per each member of the replica set.
The following example initates a three member replica set.
rs.initiate( { _id : "myReplSet", members: [ { _id : 0, host : "s1-mongo1.example.net:27018" }, { _id : 1, host : "s1-mongo2.example.net:27018" }, { _id : 2, host : "s1-mongo3.example.net:27018" } ] } )
rs.initiate()
triggers an election and
elects one of the members to be the primary.
Connect to the primary before continuing. Use rs.status()
to
locate the primary member.
Create the shard-local user administrator (optional).
Important
After you create the first user, the localhost exception is no longer available.
The first user must have privileges to create other users, such
as a user with the userAdminAnyDatabase
. This ensures
that you can create additional users after the Localhost Exception
closes.
If at least one user does not have privileges to create users, once the localhost exception closes you may be unable to create or modify users with new privileges, and therefore unable to access necessary operations.
Add a user using the db.createUser()
method. The user should
have at minimum the userAdminAnyDatabase
role on the
admin
database.
You must be connected to the primary to create users.
The following example creates the user fred
with the
userAdminAnyDatabase
role on the admin
database.
Important
Passwords should be random, long, and complex to ensure system security and to prevent or delay malicious access.
Tip
Starting in version 4.2 of the mongo
shell, you can
use the passwordPrompt()
method in conjunction with
various user authentication/management methods/commands to prompt
for the password instead of specifying the password directly in the
method/command call. However, you can still specify the password
directly as you would with earlier versions of the
mongo
shell.
admin = db.getSiblingDB("admin") admin.createUser( { user: "fred", pwd: passwordPrompt(), // or cleartext password roles: [ { role: "userAdminAnyDatabase", db: "admin" } ] } )
Enter the password when prompted. See Database User Roles for a full list of built-in roles and related to database administration operations.
Authenticate as the shard-local user administrator (optional).
Authenticate to the admin
database.
In the mongo
shell, use db.auth()
to
authenticate. For example, the following authenticate as the user
administrator fred
:
Tip
Starting in version 4.2 of the mongo
shell, you can
use the passwordPrompt()
method in conjunction with
various user authentication/management methods/commands to prompt
for the password instead of specifying the password directly in the
method/command call. However, you can still specify the password
directly as you would with earlier versions of the
mongo
shell.
db.getSiblingDB("admin").auth("fred", passwordPrompt()) // or cleartext password
Alternatively, connect a new mongo
shell to the primary
replica set member using the -u <username>
, -p <password>
, and
the --authenticationDatabase
parameters.
mongo -u "fred" -p --authenticationDatabase "admin"
If you do not specify the password to the -p
command-line option, the mongo
shell prompts for the
password.
Create the shard-local cluster administrator (optional).
The shard-local cluster administrator user has the
clusterAdmin
role, which provides privileges that allow
access to replication operations.
For a full list of roles related to replica set operations see Cluster Administration Roles.
Create a cluster administrator user and assign the
clusterAdmin
role in the admin
database:
Tip
Starting in version 4.2 of the mongo
shell, you can
use the passwordPrompt()
method in conjunction with
various user authentication/management methods/commands to prompt
for the password instead of specifying the password directly in the
method/command call. However, you can still specify the password
directly as you would with earlier versions of the
mongo
shell.
db.getSiblingDB("admin").createUser( { "user" : "ravi", "pwd" : passwordPrompt(), // or cleartext password roles: [ { "role" : "clusterAdmin", "db" : "admin" } ] } )
Enter the password when prompted.
See Cluster Administration Roles for a full list of built-in roles related to replica set and sharded cluster operations.
Connect a mongos
to the Sharded Cluster
Connect a mongos
to the cluster
Start a mongos
specifying
the keyfile using either a configuration file or a command line parameter.
Configuration File
If using a configuration file, set the
security.keyFile
to the keyfile's path and the
sharding.configDB
to the replica set name and at least
one member of the replica set in <replSetName>/<host:port>
format.
security: keyFile: <path-to-keyfile> sharding: configDB: <configReplSetName>/cfg1.example.net:27019,cfg2.example.net:27019,...
Include additional options as required
for your configuration. For instance, if you wish remote clients to
connect to your deployment or your deployment members are run on
different hosts, specify the net.bindIp
setting. For more
information, see Localhost Binding Compatibility Changes.
Start the mongos
specifying the --config
option and the
path to the configuration file.
mongos --config <path-to-config>
Command Line
If using command line parameters start the mongos
and specify
the --keyFile
and --configdb
parameters.
mongos --keyFile <path-to-keyfile> --configdb <configReplSetName>/cfg1.example.net:27019,cfg2.example.net:27019,...
Include additional options as required for your configuration. For
instance, if you wish remote clients to connect to your deployment
or your deployment members are run on different hosts, specify the
--bind_ip
. For more information, see
Localhost Binding Compatibility Changes.
Connect to a mongos
over the localhost interface.
Connect a mongo
shell to one of the
mongos
instances over the localhost
interface. You must run the mongo
shell on the same physical machine as the mongos
instance.
The localhost interface is only available since no users have been created for the deployment. The localhost interface closes after the creation of the first user.
Create the user administrator.
Important
After you create the first user, the localhost exception is no longer available.
The first user must have privileges to create other users, such
as a user with the userAdminAnyDatabase
. This ensures
that you can create additional users after the Localhost Exception
closes.
If at least one user does not have privileges to create users, once the localhost exception closes you cannot create or modify users, and therefore may be unable to perform necessary operations.
Add a user using the db.createUser()
method. The user should
have at minimum the userAdminAnyDatabase
role on the
admin
database.
Important
Passwords should be random, long, and complex to ensure system security and to prevent or delay malicious access.
The following example creates the user fred
on the
admin
database:
Tip
Starting in version 4.2 of the mongo
shell, you can
use the passwordPrompt()
method in conjunction with
various user authentication/management methods/commands to prompt
for the password instead of specifying the password directly in the
method/command call. However, you can still specify the password
directly as you would with earlier versions of the
mongo
shell.
admin = db.getSiblingDB("admin") admin.createUser( { user: "fred", pwd: passwordPrompt(), // or cleartext password roles: [ { role: "userAdminAnyDatabase", db: "admin" } ] } )
See Database User Roles for a full list of built-in roles and related to database administration operations.
Authenticate as the user administrator.
Use db.auth()
to authenticate as the user administrator
to create additional users:
Tip
Starting in version 4.2 of the mongo
shell, you can
use the passwordPrompt()
method in conjunction with
various user authentication/management methods/commands to prompt
for the password instead of specifying the password directly in the
method/command call. However, you can still specify the password
directly as you would with earlier versions of the
mongo
shell.
db.getSiblingDB("admin").auth("fred", passwordPrompt()) // or cleartext password
Enter the password when prompted.
Alternatively, connect a new mongo
shell to the target
replica set member using the -u <username>
, -p <password>
, and
the --authenticationDatabase "admin"
parameters. You must use
the Localhost Exception to connect to the mongos
.
mongo -u "fred" -p --authenticationDatabase "admin"
If you do not specify the password to the -p
command-line option, the mongo
shell prompts for the
password.
Create Administrative User for Cluster Management
The cluster administrator user has the clusterAdmin
role,
which grants access to replication and sharding operations.
Create a clusterAdmin
user in the admin
database.
The following example creates the user ravi
on the admin
database.
Important
Passwords should be random, long, and complex to ensure system security and to prevent or delay malicious access.
Tip
Starting in version 4.2 of the mongo
shell, you can
use the passwordPrompt()
method in conjunction with
various user authentication/management methods/commands to prompt
for the password instead of specifying the password directly in the
method/command call. However, you can still specify the password
directly as you would with earlier versions of the
mongo
shell.
db.getSiblingDB("admin").createUser( { "user" : "ravi", "pwd" : passwordPrompt(), // or cleartext password roles: [ { "role" : "clusterAdmin", "db" : "admin" } ] } )
See Cluster Administration Roles for a full list of built-in roles related to replica set and sharded cluster operations.
Create additional users (Optional).
Create users to allow clients to connect and access the
sharded cluster. See Database User Roles for available built-in
roles, such as read
and readWrite
.
You may also want additional administrative users.
For more information on users, see Users.
To create additional users, you must authenticate as a user with
userAdminAnyDatabase
or userAdmin
roles.
Add Shards to the Cluster
To proceed, you must be connected to the mongos
and
authenticated as the cluster administrator user for the sharded cluster.
Note
This is the cluster administrator for the sharded cluster and not the shard-local cluster administrator.
To add each shard to the cluster, use the sh.addShard()
method. If the shard is a replica set, specify the name of the replica
set and specify a member of the set. In production deployments, all
shards should be replica sets.
The following operation adds a single shard replica set to the cluster:
sh.addShard( "<replSetName>/s1-mongo1.example.net:27017")
The following operation is an example of adding a standalone mongod
shard to the cluster:
sh.addShard( "s1-mongo1.example.net:27017")
Repeat these steps until the cluster includes all shards. At this point, the sharded cluster enforces access control for the cluster as well as for internal communications between each sharded cluster component.
Enable Sharding for a Database
To proceed, you must be connected to the mongos
and
authenticated as the cluster administrator user for the sharded cluster.
Note
This is the cluster administrator for the sharded cluster and not the shard-local cluster administrator.
Enabling sharding on a database makes it possible to shard collections
within the database. Use the sh.enableSharding()
method to
enable sharding on the target database.
sh.enableSharding("<database>")
Shard a Collection
To proceed, you must be connected to the mongos
and
authenticated as the cluster administrator user for the sharded cluster.
Note
This is the cluster administrator for the sharded cluster and not the shard-local cluster administrator.
To shard a collection, use the sh.shardCollection()
method.
You must specify the full namespace of the collection and a document containing
the shard key.
Your selection of shard key affects the efficiency of sharding, as well as your ability to take advantage of certain sharding features such as zones. See the selection considerations listed in the Choosing a Shard Key.
If the collection already contains data, you must create an index on the
shard key using the db.collection.createIndex()
method before
using shardCollection()
.
If the collection is empty, MongoDB creates the index as part of
sh.shardCollection()
.
The following is an example of the sh.shardCollection()
method:
sh.shardCollection("<database>.<collection>", { <key> : <direction> } )
Next Steps
Create users to allow clients to connect to and interact with the sharded cluster.
See Database User Roles for basic built-in roles to use in creating read-only and read-write users.
x.509 Internal Authentication
For details on using x.509 for internal authentication, see Use x.509 Certificate for Membership Authentication.
To upgrade from keyfile internal authentication to x.509 internal authentication, see Upgrade from Keyfile Authentication to x.509 Authentication.