1. 26 Sep, 2012 1 commit
  2. 04 Sep, 2012 2 commits
    • antirez's avatar
      Sentinel: reply -IDONTKNOW to get-master-addr-by-name on lack of info. · 9bd0e097
      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.
      9bd0e097
    • antirez's avatar
      Sentinel: more easy master redirection if master is a slave. · 8bdde086
      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.
      8bdde086
  3. 30 Aug, 2012 1 commit
  4. 29 Aug, 2012 1 commit
  5. 28 Aug, 2012 2 commits
    • antirez's avatar
      Sentinel: Sentinel-side support for slave priority. · 3ec701e0
      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".
      3ec701e0
    • antirez's avatar
      Sentinel: suppress harmless warning by initializing 'table' to NULL. · c14e0eca
      antirez authored
      Note that the assertion guarantees that one of the if branches setting
      table is always entered.
      c14e0eca
  6. 24 Aug, 2012 2 commits
    • antirez's avatar
      Sentinel: send SCRIPT KILL on -BUSY reply and SDOWN instance. · 850789ce
      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.
      850789ce
    • antirez's avatar
      Sentinel: fixed a crash on script execution. · 01477753
      antirez authored
      The call to sentinelScheduleScriptExecution() lacked the final NULL
      argument to signal the end of arguments. This resulted into a crash.
      01477753
  7. 03 Aug, 2012 1 commit
    • antirez's avatar
      Sentinel: SENTINEL FAILOVER command implemented. · cada7f96
      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.
      cada7f96
  8. 02 Aug, 2012 1 commit
    • antirez's avatar
      Sentinel: client reconfiguration script execution. · 6275004c
      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.
      6275004c
  9. 31 Jul, 2012 3 commits
    • antirez's avatar
      Sentinel: when leader in wait-start, sense another leader as race. · fd92b366
      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.
      fd92b366
    • antirez's avatar
    • antirez's avatar
      Sentinel: abort failover when in wait-start if master is back. · 75084e05
      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.
      75084e05
  10. 28 Jul, 2012 2 commits
    • antirez's avatar
      Sentinel: scripts execution engine improved. · 3f194a9d
      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.
      3f194a9d
    • Jan-Erik Rediger's avatar
      Include sys/wait.h to avoid compiler warning · c6c19c83
      Jan-Erik Rediger authored
      gcc warned about an implicit declaration of function 'wait3'. 
      Including this header fixes this.
      c6c19c83
  11. 26 Jul, 2012 1 commit
  12. 25 Jul, 2012 2 commits
    • antirez's avatar
      baace5fc
    • antirez's avatar
      Sentinel: abort failover if no good slave is available. · 672102c2
      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.
      672102c2
  13. 24 Jul, 2012 6 commits
    • antirez's avatar
      9e5bef38
    • antirez's avatar
      Prevent a spurious +sdown event on switch. · a23a5b6c
      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.
      a23a5b6c
    • antirez's avatar
      Sentinel: debugging message removed. · d918e6f1
      antirez authored
      d918e6f1
    • antirez's avatar
      Sentinel: changes to connection handling and redirection. · 75fb6e5b
      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.
      75fb6e5b
    • antirez's avatar
      Sentinel: check that instance still exists in reply callbacks. · 2179c269
      antirez authored
      We can't be sure the instance object still exists when the reply
      callback is called.
      2179c269
    • antirez's avatar
      Sentinel: more robust failover detection as observer. · d876d6fe
      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.
      d876d6fe
  14. 23 Jul, 2012 1 commit