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https://github.com/fluencelabs/redis
synced 2025-03-18 00:20:50 +00:00
Sentinel: state machine and timeouts simplified.
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antirez
parent
4be53b1c5d
commit
3a56013acb
@ -85,7 +85,7 @@ typedef struct sentinelAddr {
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#define SENTINEL_SLAVE_RECONF_RETRY_PERIOD 10000
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#define SENTINEL_DEFAULT_PARALLEL_SYNCS 1
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#define SENTINEL_MIN_LINK_RECONNECT_PERIOD 15000
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#define SENTINEL_DEFAULT_FAILOVER_TIMEOUT (60*15*1000)
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#define SENTINEL_DEFAULT_FAILOVER_TIMEOUT (60*5*1000)
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#define SENTINEL_MAX_PENDING_COMMANDS 100
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#define SENTINEL_ELECTION_TIMEOUT 10000
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@ -105,8 +105,7 @@ typedef struct sentinelAddr {
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#define SENTINEL_FAILOVER_STATE_WAIT_NEXT_SLAVE 6 /* wait replication */
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#define SENTINEL_FAILOVER_STATE_ALERT_CLIENTS 7 /* Run user script. */
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#define SENTINEL_FAILOVER_STATE_WAIT_ALERT_SCRIPT 8 /* Wait script exec. */
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#define SENTINEL_FAILOVER_STATE_DETECT_END 9 /* Check for failover end. */
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#define SENTINEL_FAILOVER_STATE_UPDATE_CONFIG 10 /* Monitor promoted slave. */
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#define SENTINEL_FAILOVER_STATE_UPDATE_CONFIG 9 /* Monitor promoted slave. */
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#define SENTINEL_MASTER_LINK_STATUS_UP 0
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#define SENTINEL_MASTER_LINK_STATUS_DOWN 1
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@ -1693,10 +1692,6 @@ void sentinelRefreshInstanceInfo(sentinelRedisInstance *ri, const char *info) {
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ri->flags &= ~SRI_RECONF_INPROG;
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ri->flags |= SRI_RECONF_DONE;
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sentinelEvent(REDIS_NOTICE,"+slave-reconf-done",ri,"%@");
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/* If we are moving forward (a new slave is now configured)
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* we update the change_time as we are conceptually passing
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* to the next slave. */
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ri->failover_state_change_time = mstime();
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}
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}
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}
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@ -1968,7 +1963,6 @@ const char *sentinelFailoverStateStr(int state) {
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case SENTINEL_FAILOVER_STATE_WAIT_PROMOTION: return "wait_promotion";
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case SENTINEL_FAILOVER_STATE_RECONF_SLAVES: return "reconf_slaves";
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case SENTINEL_FAILOVER_STATE_ALERT_CLIENTS: return "alert_clients";
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case SENTINEL_FAILOVER_STATE_DETECT_END: return "detect_end";
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case SENTINEL_FAILOVER_STATE_UPDATE_CONFIG: return "update_config";
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default: return "unknown";
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}
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@ -2816,17 +2810,20 @@ void sentinelFailoverWaitStart(sentinelRedisInstance *ri) {
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/* If I'm not the leader, I can't continue with the failover. */
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if (!isleader) {
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int election_timeout = SENTINEL_ELECTION_TIMEOUT;
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/* The election timeout is the MIN between SENTINEL_ELECTION_TIMEOUT
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* and the configured failover timeout. */
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if (election_timeout > ri->failover_timeout)
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election_timeout = ri->failover_timeout;
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/* Abort the failover if I'm not the leader after some time. */
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if (mstime() - ri->failover_start_time > SENTINEL_ELECTION_TIMEOUT) {
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if (mstime() - ri->failover_start_time > election_timeout) {
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sentinelEvent(REDIS_WARNING,"-failover-abort-not-elected",ri,"%@");
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sentinelAbortFailover(ri);
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}
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return;
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}
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sentinelEvent(REDIS_WARNING,"+elected-leader",ri,"%@");
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/* Start the failover going to the next state if enough time has
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* elapsed. */
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ri->failover_state = SENTINEL_FAILOVER_STATE_SELECT_SLAVE;
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ri->failover_state_change_time = mstime();
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sentinelEvent(REDIS_WARNING,"+failover-state-select-slave",ri,"%@");
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@ -2835,6 +2832,8 @@ void sentinelFailoverWaitStart(sentinelRedisInstance *ri) {
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void sentinelFailoverSelectSlave(sentinelRedisInstance *ri) {
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sentinelRedisInstance *slave = sentinelSelectSlave(ri);
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/* We don't handle the timeout in this state as the function aborts
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* the failover or go forward in the next state. */
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if (slave == NULL) {
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sentinelEvent(REDIS_WARNING,"-failover-abort-no-good-slave",ri,"%@");
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sentinelAbortFailover(ri);
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@ -2852,7 +2851,16 @@ void sentinelFailoverSelectSlave(sentinelRedisInstance *ri) {
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void sentinelFailoverSendSlaveOfNoOne(sentinelRedisInstance *ri) {
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int retval;
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if (ri->promoted_slave->flags & SRI_DISCONNECTED) return;
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/* We can't send the command to the promoted slave if it is now
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* disconnected. Retry again and again with this state until the timeout
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* is reached, then abort the failover. */
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if (ri->promoted_slave->flags & SRI_DISCONNECTED) {
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if (mstime() - ri->failover_state_change_time > ri->failover_timeout) {
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sentinelEvent(REDIS_WARNING,"-failover-abort-slave-timeout",ri,"%@");
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sentinelAbortFailover(ri);
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}
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return;
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}
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/* Send SLAVEOF NO ONE command to turn the slave into a master.
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* We actually register a generic callback for this command as we don't
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@ -2869,16 +2877,11 @@ void sentinelFailoverSendSlaveOfNoOne(sentinelRedisInstance *ri) {
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/* We actually wait for promotion indirectly checking with INFO when the
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* slave turns into a master. */
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void sentinelFailoverWaitPromotion(sentinelRedisInstance *ri) {
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mstime_t elapsed = mstime() - ri->failover_state_change_time;
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if (elapsed >= SENTINEL_PROMOTION_RETRY_PERIOD) {
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sentinelEvent(REDIS_WARNING,"-promotion-timeout",ri->promoted_slave,
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"%@");
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sentinelEvent(REDIS_WARNING,"+failover-state-select-slave",ri,"%@");
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ri->failover_state = SENTINEL_FAILOVER_STATE_SELECT_SLAVE;
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ri->failover_state_change_time = mstime();
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ri->promoted_slave->flags &= ~SRI_PROMOTED;
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ri->promoted_slave = NULL;
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/* Just handle the timeout. Switching to the next state is handled
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* by the function parsing the INFO command of the promoted slave. */
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if (mstime() - ri->failover_state_change_time > ri->failover_timeout) {
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sentinelEvent(REDIS_WARNING,"-failover-abort-slave-timeout",ri,"%@");
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sentinelAbortFailover(ri);
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}
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}
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@ -3002,6 +3005,8 @@ void sentinelFailoverReconfNextSlave(sentinelRedisInstance *master) {
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}
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}
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dictReleaseIterator(di);
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/* Check if all the slaves are reconfigured and handle timeout. */
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sentinelFailoverDetectEnd(master);
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}
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@ -3049,50 +3054,46 @@ void sentinelFailoverStateMachine(sentinelRedisInstance *ri) {
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case SENTINEL_FAILOVER_STATE_RECONF_SLAVES:
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sentinelFailoverReconfNextSlave(ri);
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break;
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case SENTINEL_FAILOVER_STATE_DETECT_END:
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sentinelFailoverDetectEnd(ri);
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break;
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}
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}
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/* Abort a failover in progress with the following steps:
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* 1) Set the master back to the original one, increment the config epoch.
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* 2) Reconfig slaves to replicate to the old master.
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* 3) Reconfig the promoted slave as a slave as well. */
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/* Abort a failover in progress:
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*
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* This function can only be called before the promoted slave acknowledged
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* the slave -> master switch. Otherwise the failover can't be aborted and
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* will reach its end.
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*
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* If there is a promoted slave and we already got acknowledge of the
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* slave -> master switch, we clear our flags and redirect to the
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* new master. Eventually the config will be propagated if it is the one
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* with the greater config epoch for this master.
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*
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* Otherwise if we still did not received the acknowledgement from the
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* promoted slave, or there is no promoted slave at all, we just clear the
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* failover-in-progress state as there is nothing to do (if the promoted
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* slave for some reason actually received our "SLAVEOF NO ONE" command
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* even if we did not received the ACK, it will be reverted to slave again
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* by one of the Sentinels). */
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void sentinelAbortFailover(sentinelRedisInstance *ri) {
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dictIterator *di;
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dictEntry *de;
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int sentinel_role;
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redisAssert(ri->flags & SRI_FAILOVER_IN_PROGRESS);
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redisAssert(ri->failover_state <= SENTINEL_FAILOVER_STATE_WAIT_PROMOTION);
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/* Clear failover related flags from slaves.
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* Also if we are the leader make sure to send SLAVEOF commands to all the
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* already reconfigured slaves in order to turn them back into slaves of
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* the original master. */
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/* Clear failover related flags from slaves. */
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di = dictGetIterator(ri->slaves);
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while((de = dictNext(di)) != NULL) {
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sentinelRedisInstance *slave = dictGetVal(de);
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if (!(slave->flags & SRI_DISCONNECTED) &&
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(slave->flags & (SRI_PROMOTED|SRI_RECONF_SENT|SRI_RECONF_INPROG|
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SRI_RECONF_DONE)))
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{
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int retval;
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retval = sentinelSendSlaveOf(slave,ri->addr->ip,ri->addr->port);
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if (retval == REDIS_OK)
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sentinelEvent(REDIS_NOTICE,"-slave-reconf-undo",slave,"%@");
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}
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slave->flags &= ~(SRI_RECONF_SENT|SRI_RECONF_INPROG|SRI_RECONF_DONE);
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}
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dictReleaseIterator(di);
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sentinel_role = SENTINEL_LEADER;
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ri->flags &= ~(SRI_FAILOVER_IN_PROGRESS|SRI_FORCE_FAILOVER);
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ri->failover_state = SENTINEL_FAILOVER_STATE_NONE;
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ri->failover_state_change_time = mstime();
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if (ri->promoted_slave) {
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sentinelCallClientReconfScript(ri,sentinel_role,"abort",
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sentinelCallClientReconfScript(ri,SENTINEL_LEADER,"abort",
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ri->promoted_slave->addr,ri->addr);
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ri->promoted_slave->flags &= ~SRI_PROMOTED;
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ri->promoted_slave = NULL;
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