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mongos
mongos
¶
On this page
Synopsis¶
mongos
for “MongoDB Shard,” is a routing service for
MongoDB shard configurations that processes queries from the
application layer, and determines the location of this data in the
sharded cluster, in order to complete these operations.
From the perspective of the application, a
mongos
instance behaves identically to any other MongoDB
instance.
Options¶
-
mongos
¶
Core Options¶
-
--help
,
-h
¶
Returns information on the options and use of mongos.
-
--version
¶
Returns the mongos release number.
-
--config
<filename>
,
-f
<filename>
¶ Specifies a configuration file for runtime configuration options. The configuration file is the preferred method for runtime configuration of mongos. The options are equivalent to the command-line configuration options. See Configuration File Options for more information.
Ensure the configuration file uses ASCII encoding. The mongos instance does not support configuration files with non-ASCII encoding, including UTF-8.
-
--verbose
,
-v
¶
Increases the amount of internal reporting returned on standard output or in log files. Increase the verbosity with the
-v
form by including the option multiple times, (e.g.-vvvvv
.)
-
--quiet
¶
Runs the mongos in a quiet mode that attempts to limit the amount of output.
This option suppresses:
- output from database commands
- replication activity
- connection accepted events
- connection closed events
-
--port
<port>
¶ Default: 27017
Specifies the TCP port on which the MongoDB instance listens for client connections.
-
--bind_ip
<ip address>
¶ Default: All interfaces.
Changed in version 2.6.0: The
deb
andrpm
packages include a default configuration file (/etc/mongod.conf
) that sets--bind_ip
to127.0.0.1
.The IP addresses and/or full Unix domain socket paths on which mongos should listen for client connections. You may attach mongos to any interface. To bind to multiple addresses, enter a list of comma-separated values.
Example
localhost,/tmp/mongod.sock
You can specify both IPv4 and IPv6 addresses, or hostnames that resolve to an IPv4 or IPv6 address.
Example
localhost, 2001:0DB8:e132:ba26:0d5c:2774:e7f9:d513
Note
If specifying an IPv6 address or a hostname that resolves to an IPv6 address to
--bind_ip
, you must start mongos with--ipv6
to enable IPv6 support. Specifying an IPv6 address to--bind_ip
does not enable IPv6 support.If specifying a link-local IPv6 address (
fe80::/10
), you must append the zone index to that address (i.e.fe80::<address>%<adapter-name>
).Example
localhost,fe80::a00:27ff:fee0:1fcf%enp0s3
Tip
To avoid downtime, give each config server a logical DNS name (unrelated to the server’s physical or virtual hostname). Without logical DNS names, moving or renaming a config server requires shutting down every
mongod
andmongos
instance in the sharded cluster.Warning
Before binding to a non-localhost (e.g. publicly accessible) IP address, ensure you have secured your cluster from unauthorized access. For a complete list of security recommendations, see Security Checklist. At minimum, consider enabling authentication and hardening network infrastructure.
To bind to all IPv4 addresses, enter
0.0.0.0
.To bind to all IPv4 and IPv6 addresses, enter
0.0.0.0,::
.
-
--maxConns
<number>
¶ The maximum number of simultaneous connections that mongos will accept. This setting has no effect if it is higher than your operating system’s configured maximum connection tracking threshold.
Do not assign too low of a value to this option, or you will encounter errors during normal application operation.
This is particularly useful for a
mongos
if you have a client that creates multiple connections and allows them to timeout rather than closing them.In this case, set
maxIncomingConnections
to a value slightly higher than the maximum number of connections that the client creates, or the maximum size of the connection pool.This setting prevents the
mongos
from causing connection spikes on the individual shards. Spikes like these may disrupt the operation and memory allocation of the sharded cluster.Note
Changed in version 2.6: MongoDB removed the upward limit on the
maxIncomingConnections
setting.
-
--syslog
¶
Sends all logging output to the host’s syslog system rather than to standard output or to a log file. , as with
--logpath
.The
--syslog
option is not supported on Windows.
-
--syslogFacility
<string>
¶ Default: user
Specifies the facility level used when logging messages to syslog. The value you specify must be supported by your operating system’s implementation of syslog. To use this option, you must enable the
--syslog
option..
-
--logpath
<path>
¶ Sends all diagnostic logging information to a log file instead of to standard output or to the host’s syslog system. MongoDB creates the log file at the path you specify.
By default, MongoDB will move any existing log file rather than overwrite it. To instead append to the log file, set the
--logappend
option.
-
--logappend
¶
Appends new entries to the end of the existing log file when the mongos instance restarts. Without this option,
mongod
will back up the existing log and create a new file.
-
--timeStampFormat
<string>
¶ Default: iso8601-local
The time format for timestamps in log messages. Specify one of the following values:
Value Description ctime
Displays timestamps as Wed Dec 31 18:17:54.811
.iso8601-utc
Displays timestamps in Coordinated Universal Time (UTC) in the ISO-8601 format. For example, for New York at the start of the Epoch: 1970-01-01T00:00:00.000Z
iso8601-local
Displays timestamps in local time in the ISO-8601 format. For example, for New York at the start of the Epoch: 1969-12-31T19:00:00.000-0500
-
--pidfilepath
<path>
¶ Specifies a file location to hold the process ID of the mongos process where mongos will write its PID. This is useful for tracking the mongos process in combination with the the
--fork
option. Without a specified--pidfilepath
option, the process creates no PID file.
-
--keyFile
<file>
¶ Specifies the path to a key file that stores the shared secret that MongoDB instances use to authenticate to each other in a sharded cluster or replica set.
--keyFile
implies--auth
. See Internal Authentication for more information.
-
--setParameter
<options>
¶ Specifies one of the MongoDB parameters described in MongoDB Server Parameters. You can specify multiple
setParameter
fields.
-
--httpinterface
¶
New in version 2.6.
Enables the HTTP interface. Enabling the interface can increase network exposure.
Leave the HTTP interface disabled for production deployments. If you do enable this interface, you should only allow trusted clients to access this port. See Firewalls.
Note
- While MongoDB Enterprise does support Kerberos authentication, Kerberos is not supported in HTTP status interface in any version of MongoDB.
-
--nounixsocket
¶
Disables listening on the UNIX domain socket.
--nounixsocket
applies only to Unix-based systems.The mongos process always listens on the UNIX socket unless one of the following is true:
--nounixsocket
is setnet.bindIp
is not setnet.bindIp
does not specify127.0.0.1
-
--unixSocketPrefix
<path>
¶ Default: /tmp
The path for the UNIX socket.
--unixSocketPrefix
applies only to Unix-based systems.If this option has no value, the mongos process creates a socket with
/tmp
as a prefix. MongoDB creates and listens on a UNIX socket unless one of the following is true:net.unixDomainSocket.enabled
isfalse
--nounixsocket
is setnet.bindIp
is not setnet.bindIp
does not specify127.0.0.1
-
--filePermissions
<path>
¶ Default:
0700
Sets the permission for the UNIX domain socket file.
--filePermissions
applies only to Unix-based systems.
Sharded Cluster Options¶
-
--configdb
<config1>,<config2>,<config3>
¶ Specifies the configuration database for the sharded cluster. You must specify either 1 or 3 configuration servers, in a comma separated list. Always use 3 config servers in production environments.
All
mongos
instances must specify the exact same value for--configdb
If your configuration databases reside in more that one data center, order the hosts so that first config sever in the list is the closest to the majority of your
mongos
instances.Warning
Never remove a config server from this setting, even if the config server is not available or offline.
-
--localThreshold
¶
Default: 15
Specifies the ping time, in milliseconds, that
mongos
uses to determine which secondary replica set members to pass read operations from clients. The default value of15
corresponds to the default value in all of the client drivers.When
mongos
receives a request that permits reads to secondary members, themongos
will:Find the member of the set with the lowest ping time.
Construct a list of replica set members that is within a ping time of 15 milliseconds of the nearest suitable member of the set.
If you specify a value for the
--localThreshold
option,mongos
will construct the list of replica members that are within the latency allowed by this value.Select a member to read from at random from this list.
The ping time used for a member compared by the
--localThreshold
setting is a moving average of recent ping times, calculated at most every 10 seconds. As a result, some queries may reach members above the threshold until themongos
recalculates the average.See the Member Selection section of the read preference documentation for more information.
-
--upgrade
¶
Updates the meta data format used by the config database.
-
--chunkSize
<value>
¶ Default: 64
Determines the size in megabytes of each chunk in the sharded cluster. A size of 64 megabytes is ideal in most deployments: larger chunk size can lead to uneven data distribution; smaller chunk size can lead to inefficient movement of chunks between nodes.
--chunkSize
affects chunk size only when you initialize the cluster for the first time. If you later modify the option, the new value has no effect. See the Modify Chunk Size in a Sharded Cluster procedure if you need to change the chunk size on an existing sharded cluster.
-
--noAutoSplit
¶
Disables
mongos
from automatically splitting chunks for sharded collections. If set on allmongos
instances, this prevents MongoDB from creating new chunks as the data in a collection grows.Because any
mongos
in a cluster can create a split, to totally disable splitting in a cluster you must set--noAutoSplit
on allmongos
.Warning
With
--noAutoSplit
specified, the data in your sharded cluster may become imbalanced over time. Use the option with caution.
TLS/SSL Options¶
See
Configure mongod and mongos for TLS/SSL for full documentation of MongoDB’s support.
-
--sslOnNormalPorts
¶
Deprecated since version 2.6: Use
--sslMode requireSSL
instead.Enables TLS/SSL for mongos.
With
--sslOnNormalPorts
, a mongos requires TLS/SSL encryption for all connections on the default MongoDB port, or the port specified by--port
. By default,--sslOnNormalPorts
is disabled.Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.
-
--sslMode
<mode>
¶ New in version 2.6.
Enables TLS/SSL or mixed TLS/SSL used for all network connections. The argument to the
--sslMode
option can be one of the following:Value Description disabled
The server does not use TLS/SSL. allowSSL
Connections between servers do not use TLS/SSL. For incoming connections, the server accepts both TLS/SSL and non-TLS/non-SSL. preferSSL
Connections between servers use TLS/SSL. For incoming connections, the server accepts both TLS/SSL and non-TLS/non-SSL. requireSSL
The server uses and accepts only TLS/SSL encrypted connections. Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.
-
--sslPEMKeyFile
<filename>
¶ Specifies the
.pem
file that contains both the TLS/SSL certificate and key. Specify the file name of the.pem
file using relative or absolute paths.You must specify
--sslPEMKeyFile
when TLS/SSL is enabled.Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.
-
--sslPEMKeyPassword
<value>
¶ Specifies the password to de-crypt the certificate-key file (i.e.
--sslPEMKeyFile
). Use the--sslPEMKeyPassword
option only if the certificate-key file is encrypted. In all cases, the mongos will redact the password from all logging and reporting output.Changed in version 2.6: If the private key in the PEM file is encrypted and you do not specify the
--sslPEMKeyPassword
option, the mongos will prompt for a passphrase. See SSL Certificate Passphrase.Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.
-
--clusterAuthMode
<option>
¶ Default: keyFile
New in version 2.6.
The authentication mode used for cluster authentication. If you use internal x.509 authentication, specify so here. This option can have one of the following values:
Value Description keyFile
Use a keyfile for authentication. Accept only keyfiles. sendKeyFile
For rolling upgrade purposes. Send a keyfile for authentication but can accept both keyfiles and x.509 certificates. sendX509
For rolling upgrade purposes. Send the x.509 certificate for authentication but can accept both keyfiles and x.509 certificates. x509
Recommended. Send the x.509 certificate for authentication and accept only x.509 certificates. Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.
-
--sslClusterFile
<filename>
¶ New in version 2.6.
Specifies the
.pem
file that contains the x.509 certificate-key file for membership authentication for the cluster or replica set.If
--sslClusterFile
does not specify the.pem
file for internal cluster authentication, the cluster uses the.pem
file specified in the--sslPEMKeyFile
option.Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.
-
--sslClusterPassword
<value>
¶ New in version 2.6.
Specifies the password to de-crypt the x.509 certificate-key file specified with
--sslClusterFile
. Use the--sslClusterPassword
option only if the certificate-key file is encrypted. In all cases, the mongos will redact the password from all logging and reporting output.If the x.509 key file is encrypted and you do not specify the
--sslClusterPassword
option, the mongos will prompt for a passphrase. See SSL Certificate Passphrase.Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.
-
--sslCAFile
<filename>
¶ New in version 2.4.
Specifies the
.pem
file that contains the root certificate chain from the Certificate Authority. Specify the file name of the.pem
file using relative or absolute paths.Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.
Warning
If the
--sslCAFile
option and its target file are not specified, x.509 client and member authentication will not function.mongod
, andmongos
in sharded systems, will not be able to verify the certificates of processes connecting to it against the trusted certificate authority (CA) that issued them, breaking the certificate chain.As of version 2.6.4,
mongod
will not start with x.509 authentication enabled if the CA file is not specified.
-
--sslCRLFile
<filename>
¶ New in version 2.4.
Specifies the the
.pem
file that contains the Certificate Revocation List. Specify the file name of the.pem
file using relative or absolute paths.Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.
-
--sslAllowConnectionsWithoutCertificates
¶
New in version 2.4.
Changed in version 3.0.0:
--sslWeakCertificateValidation
became--sslAllowConnectionsWithoutCertificates
. For compatibility, MongoDB processes continue to accept--sslWeakCertificateValidation
, but all users should update their configuration files.Disables the requirement for TLS/SSL certificate validation that
--sslCAFile
enables. With the--sslAllowConnectionsWithoutCertificates
option, the mongos will accept connections when the client does not present a certificate when establishing the connection.If the client presents a certificate and the mongos has
--sslAllowConnectionsWithoutCertificates
enabled, the mongos will validate the certificate using the root certificate chain specified by--sslCAFile
and reject clients with invalid certificates.Use the
--sslAllowConnectionsWithoutCertificates
option if you have a mixed deployment that includes clients that do not or cannot present certificates to the mongos.Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.
-
--sslAllowInvalidCertificates
¶
New in version 2.6.
Bypasses the validation checks for TLS/SSL certificates on other servers in the cluster and allows the use of invalid certificates.
When using the
--sslAllowInvalidCertificates
setting, MongoDB logs a warning regarding the use of the invalid certificate.Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.
-
--sslAllowInvalidHostnames
¶
New in version 3.0.
Disables the validation of the hostnames in TLS/SSL certificates, when connecting to other members of the replica set or sharded cluster for inter-process authentication. This allows mongos to connect to other members if the hostnames in their certificates do not match their configured hostname.
Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.
-
--sslDisabledProtocols
<protocol(s)>
¶ New in version 3.0.7.
Prevents a MongoDB server running with SSL from accepting incoming connections that use a specific protocol or protocols.
--sslDisabledProtocols
recognizes the following protocols:TLS1_0
,TLS1_1
, andTLS1_2
. Specifying an unrecognized protocol will prevent the server from starting.To specify multiple protocols, use a comma separated list of protocols.
Members of replica sets and sharded clusters must speak at least one protocol in common.
See also
-
--sslFIPSMode
¶
New in version 2.4.
Directs the mongos to use the FIPS mode of the installed OpenSSL library. Your system must have a FIPS compliant OpenSSL library to use the
--sslFIPSMode
option.Note
FIPS-compatible SSL is available only in MongoDB Enterprise. See Configure MongoDB for FIPS for more information.
Audit Options¶
-
--auditDestination
¶
New in version 2.6.
Enables auditing and specifies where mongos sends all audit events.
--auditDestination
can have one of the following values:Value Description syslog
Output the audit events to syslog in JSON format. Not available on Windows. Audit messages have a syslog severity level of
info
and a facility level ofuser
.The syslog message limit can result in the truncation of audit messages. The auditing system will neither detect the truncation nor error upon its occurrence.
console
Output the audit events to stdout
in JSON format.file
Output the audit events to the file specified in --auditPath
in the format specified in--auditFormat
.Note
Available only in MongoDB Enterprise.
-
--auditFormat
¶
New in version 2.6.
Specifies the format of the output file for auditing if
--auditDestination
isfile
. The--auditFormat
option can have one of the following values:Value Description JSON
Output the audit events in JSON format to the file specified in --auditPath
.BSON
Output the audit events in BSON binary format to the file specified in --auditPath
.Printing audit events to a file in JSON format degrades server performance more than printing to a file in BSON format.
Note
Available only in MongoDB Enterprise.
-
--auditPath
¶
New in version 2.6.
Specifies the output file for auditing if
--auditDestination
has value offile
. The--auditPath
option can take either a full path name or a relative path name.Note
Available only in MongoDB Enterprise.
-
--auditFilter
¶
New in version 2.6.
Specifies the filter to limit the types of operations the audit system records. The option takes a string representation of a query document of the form:
The
<field>
can be any field in the audit message, including fields returned in the param document. The<expression>
is a query condition expression.To specify an audit filter, enclose the filter document in single quotes to pass the document as a string.
To specify the audit filter in a configuration file, you must use the YAML format of the configuration file.
Note
Available only in MongoDB Enterprise.
Additional Options¶
-
--ipv6
¶
Enables IPv6 support. mongos disables IPv6 support by default.
Setting
--ipv6
does not direct the mongos to listen on any local IPv6 addresses or interfaces. To configure the mongos to listen on an IPv6 interface, you must configure--bind_ip
with one or more IPv6 addresses or hostnames that resolve to IPv6 addresses.
-
--jsonp
¶
Permits JSONP access via an HTTP interface. Enabling the interface can increase network exposure. The
--jsonp
option enables the HTTP interface, even if theHTTP interface
option is disabled.
-
--noscripting
¶
Disables the scripting engine.