replSetStepDown
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Description
-
replSetStepDown
-
Instructs the primary of the replica set to become a secondary. After the primary steps down, eligble secondaries will hold an election for primary.
The command does not immediately step down the primary. If no
electable
secondaries 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 command 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
replSetStepDown: <seconds>
.For a detailed explanation of the command ‘s execution, see Behavior.
Note
The command is only valid against the primary and throws an error if run on a non-primary member.
The
replSetStepDown
can only run on theadmin
database and has the following prototype form:replSetStepDown
takes the following fields as arguments:Field Type Description replSetStepDown
number The 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
60
seconds.The stepdown period starts from the time that the
mongod
receives the command. The stepdown period must be greater than thesecondaryCatchUpPeriodSecs
.secondaryCatchUpPeriodSecs
number Optional. The number of seconds that the
mongod
will wait for an electable secondary to catch up to the primary.When specified,
secondaryCatchUpPeriodSecs
overrides the default wait time of either10
seconds or ifforce: true
,0
seconds.force
boolean Optional. A boolean that determines whether the primary steps down if no electable and up-to-date secondary exists within the wait period.
If
true
, the primary steps down even if no suitable secondary member exists; this could lead to rollbacks if a secondary with replication lag becomes the new primary.If
false
, the primary does not step down if no suitable secondary member exists and the command returns an error.Defaults to
false
.
Behavior
Concurrent Operations
The replSetStepDown
command 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 command 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 command errors. You can override this behavior and issue with command with the force: true
option to immediately step down the primary.
Once the primary steps down successfully, that node cannot become the primary for the remainder of the replSetStepDown: <seconds>
period, which began when the node received the command.
Client Connections
The replSetStepDown
command forces all clients currently connected to the database to disconnect. This helps ensure that the clients maintain an accurate view of the replica set.
Because the disconnect includes the connection used to run the command, you cannot retrieve the return status of the command if the command completes successfully. You can only retrieve the return status of the command if it errors. When running the command 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 replSetStepDown
command is received until either a new primary is elected, or if there are no electable secondaries, the original primary resumes normal operation. The time period where writes fail is at maximum:
secondaryCatchUpPeriodSecs
(10s by default) + electionTimeoutMillis
(10s by default).
Election Handoff
Changed in version 3.6.7: If the parameter enableElectionHandoff
is true (default), when a primary steps down from rs.stepDown()
(or the replSetStepDown
command without the force: true
), the stepped-down primary nominates an eligible secondary to call an election immediately. Otherwise, secondaries can wait up to settings.electionTimeoutMillis
before calling an election. The stepped down primary does not wait for the effects of the handoff. For more information, see enableElectionHandoff
.
Examples
Step Down with Default Options
The following example, run on the current primary, attempts to step down the member for 120
seconds.
The operation waits up to the default 10
seconds for a secondary to catch up. If no suitable secondary exists, the primary does not step down and the command errors.
Note
All writes to the primary fail during the period starting when the replSetStepDown
command is received until either a new primary is elected, or if there are no electable secondaries, the original primary resumes normal operation. The time period where writes fail is at maximum:
secondaryCatchUpPeriodSecs
(10s by default) + electionTimeoutMillis
(10s by default).
Specify Wait Time for Secondary Catch Up
The following example, run on the current primary, attempts to step down the member for 120
seconds, waiting up to 15
seconds for an electable secondary to catch up. If no suitable secondary exists, the primary does not step down and the command errors.
Note
All writes to the primary fail during the period starting when the replSetStepDown
command is received until either a new primary is elected, or if there are no electable secondaries, the original primary resumes normal operation. The time period where writes fail is at maximum:
secondaryCatchUpPeriodSecs
(10s by default) + electionTimeoutMillis
(10s by default).
Specify Secondary Catch Up with Force Step Down
The following example, run on the current primary, attempts to step down the member for 120
seconds, waiting up to 15
seconds for an electable secondary to catch up. Because of the force: true
option, the primary steps down even if no suitable secondary exists.
Note
All writes to the primary fail during the period starting when the replSetStepDown
command is received until either a new primary is elected, or if there are no electable secondaries, the original primary resumes normal operation. The time period where writes fail is at maximum:
secondaryCatchUpPeriodSecs
(10s by default) + electionTimeoutMillis
(10s by default).
See also