- Reference >
mongo
Shell Methods >- Replication Methods >
- rs.addArb()
rs.addArb()¶
On this page
Description¶
-
rs.
addArb
(host)¶ Adds a new arbiter to an existing replica set.
Warning
In general, avoid deploying more than one arbiter per replica set.
The
rs.addArb()
method takes the following parameter:Parameter Type Description host
string Specifies the hostname and optionally the port number of the arbiter member to add to replica set. For the following MongoDB versions,
pv1
increases the likelihood ofw:1
rollbacks compared topv0
for replica sets with arbiters:- MongoDB 3.4.1
- MongoDB 3.4.0
- MongoDB 3.2.11 or earlier
IP Binding¶
Starting in MongoDB 3.6, MongoDB binaries, mongod
and
mongos
, bind to localhost (127.0.0.1
) by default. If the
net.ipv6
configuration file setting or the --ipv6
command line option is set for the binary, the binary additionally binds
to the IPv6 address ::1
.
Previously, starting from MongoDB 2.6, only the binaries from the official MongoDB RPM (Red Hat, CentOS, Fedora Linux, and derivatives) and DEB (Debian, Ubuntu, and derivatives) packages bind to localhost by default.
When bound only to the localhost, these MongoDB 3.6 binaries can only
accept connections from clients (including the mongo
shell,
other members in your deployment for replica sets and sharded clusters)
that are running on the same machine. Remote clients cannot connect to
the binaries bound only to localhost.
To override and bind to other ip addresses, you can use the
net.bindIp
configuration file setting or the
--bind_ip
command-line option to specify a list of ip
addresses.
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.
For example, the following mongod
instance binds to both the
localhost and the sample ip address 198.51.100.1
:
In order to connect to this instance, remote clients must specify the
ip address 198.51.100.1
or the hostname associated with the ip
address: