rs.stepDown()
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Description
rs.stepDown(stepDownSecs, secondaryCatchUpPeriodSecs)Instructs the primary of the replica set to become a secondary. After the primary steps down, eligible secondaries will hold an election for primary.
The method does not immediately step down the primary. If no
electablesecondaries are up to date with the primary, the primary waits up tosecondaryCatchUpPeriodSecs(by default 10 seconds) for a secondary to catch up. Once an electable secondary is available, the method steps down the primary.Once stepped down, the original primary becomes a secondary and is ineligible from becoming primary again for the remainder of time specified by
stepDownSecs.For a detailed explanation of the method 's execution, see Behavior.
Note
The method is only valid against the primary and throws an error if run on a non-primary member.
Important
mongosh Method
This page documents a
mongoshmethod. This is not the documentation for database commands or language-specific drivers, such as Node.js.For the database command, see the
replSetStepDowncommand.For MongoDB API drivers, refer to the language-specific MongoDB driver documentation.
For the legacy
mongoshell documentation, refer to the documentation for the corresponding MongoDB Server release:The
rs.stepDown()method has the following parameters:ParameterTypeDescriptionstepDownSecsnumberThe number of seconds to step down the primary, during which time the stepdown member is ineligible for becoming primary. If you specify a non-numeric value, the command uses
60seconds.The stepdown period starts from the time that the
mongodreceives the command. The stepdown period must be greater than thesecondaryCatchUpPeriodSecs.secondaryCatchUpPeriodSecsnumberOptional. The number of seconds that
mongodwill wait for an electable secondary to catch up to the primary.When specified,
secondaryCatchUpPeriodSecsoverrides the default wait time of10seconds.
Behavior
Concurrent Operations
The rs.stepDown() method attempts to
terminate long running user operations that block the primary
from stepping down, such as an index build, a write operation or a
map-reduce job.
Availability of Eligible Secondaries
The method then initiates a catchup period where it waits up to
secondaryCatchUpPeriodSeconds, by default 10 seconds, for a
secondary to become up-to-date with the primary. The primary only steps
down if a secondary is up-to-date with the primary during the
catchup period to prevent rollbacks.
If no electable secondary meets this criterion by the end of the waiting period, the primary does not step down and the method errors.
Once the primary steps down successfully, that node cannot become the
primary for the remainder of the stepDownSecs period,
which began when the node received the method.
Client Connections
Starting in MongoDB 4.2, rs.stepDown() method no
longer closes all client connections.
In MongoDB 4.0 and earlier, rs.stepDown() method
closes all client connections during the step down. Because the
disconnect includes the connection used to run the method,
you cannot retrieve the return status of the method if the
method completes successfully. You can only retrieve the
return status of the method if it errors. When running the
4.0 and earlier method in a script, the script should
account for this behavior.
Writes During Stepdown
Note
All writes to the primary fail during the period starting when the
rs.stepDown() method is received until either a new
primary is elected, or if there are no electable secondaries, the
original primary resumes normal operation.
Writes that were in progress when rs.stepDown() is run
are killed. In-progress transactions
also fail with TransientTransactionError and can be
retried as a whole.
The time period where writes fail is at maximum:
secondaryCatchUpPeriodSecs (10s by default) +
electionTimeoutMillis (10s by default).
Election Handoff
When you step down a primary using rs.stepDown() or
replSetStepDown without setting the force field to
true, the stepped-down primary nominates an eligible secondary
to call an election immediately.