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Sentinel: send SLAVEOF with MULTI, CLIENT KILL, CONFIG REWRITE.

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This implements the new Sentinel-Client protocol for the Sentinel part:
now instances are reconfigured using a transaction that ensures that the
config is rewritten in the target instance, and that clients lose the
connection with the instance, in order to be forced to: ask Sentinel,
reconnect to the instance, and verify the instance role with the new
ROLE command.
This commit is contained in:
antirez 2014-06-17 11:03:21 +02:00
parent bb2011d992
commit 2c17591224
1 changed files with 38 additions and 6 deletions
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40
src/sentinel.c
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@ -3203,21 +3203,53 @@ int sentinelSendSlaveOf(sentinelRedisInstance *ri, char *host, int port) {
ll2string(portstr,sizeof(portstr),port);
/* If host is NULL we send SLAVEOF NO ONE that will turn the instance
* into a master. */
if (host == NULL) {
host = "NO";
memcpy(portstr,"ONE",4);
}
/* In order to send SLAVEOF in a safe way, we send a transaction performing
* the following tasks:
* 1) Reconfigure the instance according to the specified host/port params.
* 2) Rewrite the configuraiton.
* 3) Disconnect all clients (but this one sending the commnad) in order
* to trigger the ask-master-on-reconnection protocol for connected
* clients.
*
* Note that we don't check the replies returned by commands, since we
* will observe instead the effects in the next INFO output. */
retval = redisAsyncCommand(ri->cc,
sentinelDiscardReplyCallback, NULL, "MULTI");
if (retval == REDIS_ERR) return retval;
ri->pending_commands++;
retval = redisAsyncCommand(ri->cc,
sentinelDiscardReplyCallback, NULL, "SLAVEOF %s %s", host, portstr);
if (retval == REDIS_ERR) return retval;
ri->pending_commands++;
retval = redisAsyncCommand(ri->cc,
sentinelDiscardReplyCallback, NULL, "CONFIG REWRITE");
if (retval == REDIS_ERR) return retval;
ri->pending_commands++;
if (redisAsyncCommand(ri->cc,
sentinelDiscardReplyCallback, NULL, "CONFIG REWRITE") == REDIS_OK)
{
/* CLIENT KILL TYPE <type> is only supported starting from Redis 2.8.12,
* however sending it to an instance not understanding this command is not
* an issue because CLIENT is variadic command, so Redis will not
* recognized as a syntax error, and the transaction will not fail (but
* only the unsupported command will fail). */
retval = redisAsyncCommand(ri->cc,
sentinelDiscardReplyCallback, NULL, "CLIENT KILL TYPE normal");
if (retval == REDIS_ERR) return retval;
ri->pending_commands++;
}
retval = redisAsyncCommand(ri->cc,
sentinelDiscardReplyCallback, NULL, "EXEC");
if (retval == REDIS_ERR) return retval;
ri->pending_commands++;
return REDIS_OK;
}