- 26 Sep, 2012 1 commit
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antirez authored
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- 04 Sep, 2012 2 commits
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antirez authored
If we don't have any clue about a master since it never replied to INFO so far, reply with an -IDONTKNOW error to SENTINEL get-master-addr-by-name requests.
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antirez authored
Before this commit Sentienl used to redirect master ip/addr if the current instance reported to be a slave only if this was the first INFO output received, and the role was found to be slave. Now instead also if we find that the runid is different, and the reported role is slave, we also redirect to the reported master ip/addr. This unifies the behavior of Sentinel in the case of a reboot (where it will see the first INFO output with the wrong role and will perform the redirection), with the behavior of Sentinel in the case of a change in what it sees in the INFO output of the master.
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- 30 Aug, 2012 1 commit
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antirez authored
Older versions of Redis (before 2.4.17) don't publish the runid field in INFO. This commit makes Sentinel able to handle that without crashing.
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- 29 Aug, 2012 1 commit
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antirez authored
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- 28 Aug, 2012 2 commits
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antirez authored
The slave priority that is now published by Redis in INFO output is now used by Sentinel in order to select the slave with minimum priority for promotion, and in order to consider slaves with priority set to 0 as not able to play the role of master (they will never be promoted by Sentinel). The "slave-priority" field is now one of the fileds that Sentinel publishes when describing an instance via the SENTINEL commands such as "SENTINEL slaves mastername".
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antirez authored
Note that the assertion guarantees that one of the if branches setting table is always entered.
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- 24 Aug, 2012 2 commits
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antirez authored
From the point of view of Redis an instance replying -BUSY is down, since it is effectively not able to reply to user requests. However a looping script is a recoverable condition in Redis if the script still did not performed any write to the dataset. In that case performing a fail over is not optimal, so Sentinel now tries to restore the normal server condition killing the script with a SCRIPT KILL command. If the script already performed some write before entering an infinite (or long enough to timeout) loop, SCRIPT KILL will not work and the fail over will be triggered anyway.
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antirez authored
The call to sentinelScheduleScriptExecution() lacked the final NULL argument to signal the end of arguments. This resulted into a crash.
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- 03 Aug, 2012 1 commit
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antirez authored
This command can be used in order to force a Sentinel instance to start a failover for the specified master, as leader, forcing the failover even if the master is up. The commit also adds some minor refactoring and other improvements to functions already implemented that make them able to work when the master is not in SDOWN condition. For instance slave selection assumed that we ask INFO every second to every slave, this is true only when the master is in SDOWN condition, so slave selection did not worked when the master was not in SDOWN condition.
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- 02 Aug, 2012 1 commit
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antirez authored
This commit adds support to optionally execute a script when one of the following events happen: * The failover starts (with a slave already promoted). * The failover ends. * The failover is aborted. The script is called with enough parameters (documented in the example sentinel.conf file) to provide information about the old and new ip:port pair of the master, the role of the sentinel (leader or observer) and the name of the master. The goal of the script is to inform clients of the configuration change in a way specific to the environment Sentinel is running, that can't be implemented in a genereal way inside Sentinel itself.
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- 31 Jul, 2012 3 commits
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antirez authored
When we are in wait start, if another leader (or any other external entity) turns a slave into a master, abort the failover, and detect it as an observer. Note that the wait-start state is mainly there for this reason but the abort was yet not implemented. This adds a new sentinel event -failover-abort-race.
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antirez authored
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antirez authored
When we are a Leader Sentinel in wait-start state, starting with this commit the failover is aborted if the master returns online. This improves the way we handle a notable case of net split, that is the split between Sentinels and Redis servers, that will be a very common case of split becase Sentinels will often be installed in the client's network and servers can be in a differnt arm of the network. When Sentinels and Redis servers are isolated the master is in ODOWN condition since the Sentinels can agree about this state, however the failover does not start since there are no good slaves to promote (in this specific case all the slaves are unreachable). However when the split is resolved, Sentinels may sense the slave back a moment before they sense the master is back, so the failover may start without a good reason (since the master is actually working too). Now this condition is reversible, so the failover will be aborted immediately after if the master is detected to be working again, that is, not in SDOWN nor in ODOWN condition.
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- 28 Jul, 2012 2 commits
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antirez authored
We no longer use a vanilla fork+execve but take a queue of jobs of scripts to execute, with retry on error, timeouts, and so forth. Currently this is used only for notifications but soon the ability to also call clients reconfiguration scripts will be added.
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Jan-Erik Rediger authored
gcc warned about an implicit declaration of function 'wait3'. Including this header fixes this.
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- 26 Jul, 2012 1 commit
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antirez authored
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- 25 Jul, 2012 2 commits
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antirez authored
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antirez authored
The previous behavior of the state machine was to wait some time and retry the slave selection, but this is not robust enough against drastic changes in the conditions of the monitored instances. What we do now when the slave selection fails is to abort the failover and return back monitoring the master. If the ODOWN condition is still present a new failover will be triggered and so forth. This commit also refactors the code we use to abort a failover.
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- 24 Jul, 2012 6 commits
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antirez authored
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antirez authored
When we reset the master we should start with clean timestamps for ping replies otherwise we'll detect a spurious +sdown event, because on +master-switch event the previous master instance was probably in +sdown condition. Since we updated the address we should count time from scratch again. Also this commit makes sure to explicitly reset the count of pending commands, now we can do this because of the new way the hiredis link is closed.
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antirez authored
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antirez authored
We disconnect the Redis instances hiredis link in a more robust way now. Also we change the way we perform the redirection for the +switch-master event, that is not just an instance reset with an address change. Using the same system we now implement the +redirect-to-master event that is triggered by an instance that is configured to be master but found to be a slave at the first INFO reply. In that case we monitor the master instead, logging the incident as an event.
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antirez authored
We can't be sure the instance object still exists when the reply callback is called.
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antirez authored
Sentinel observers detect failover checking if a slave attached to the monitored master turns into its replication state from slave to master. However while this change may in theory only happen after a SLAVEOF NO ONE command, in practie it is very easy to reboot a slave instance with a wrong configuration that turns it into a master, especially if it was a past master before a successfull failover. This commit changes the detection policy so that if an instance goes from slave to master, but at the same time the runid has changed, we sense a reboot, and in that case we don't detect a failover at all. This commit also introduces the "reboot" sentinel event, that is logged at "warning" level (so this will trigger an admin notification). The commit also fixes a problem in the disconnect handler that assumed that the instance object always existed, that is not the case. Now we no longer assume that redisAsyncFree() will call the disconnection handler before returning.
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- 23 Jul, 2012 1 commit
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antirez authored
This commit implements the first, beta quality implementation of Redis Sentinel, a distributed monitoring system for Redis with notification and automatic failover capabilities. More info at http://redis.io/topics/sentinel
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