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Sentinel: Redis-side support for slave priority.

A Redis slave can now be configured with a priority, that is an integer
number that is shown in INFO output and can be get and set using the
redis.conf file or the CONFIG GET/SET command.

This field is used by Sentinel during slave election. A slave with lower
priority is preferred. A slave with priority zero is never elected (and
is considered to be impossible to elect even if it is the only slave
available).

A next commit will add support in the Sentinel side as well.
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1 parent c14e0ec commit 169a44cbd6b6a143b282206d754b71cd3af0c963 @antirez committed Aug 28, 2012
Showing with 12 additions and 2 deletions.
  1. +7 −0 src/config.c
  2. +3 −0 src/redis.c
  3. +2 −2 src/redis.h
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@@ -354,6 +354,8 @@ void loadServerConfigFromString(char *config) {
if ((server.stop_writes_on_bgsave_err = yesnotoi(argv[1])) == -1) {
err = "argument must be 'yes' or 'no'"; goto loaderr;
}
+ } else if (!strcasecmp(argv[0],"slave-priority") && argc == 2) {
+ server.slave_priority = atoi(argv[1]);
} else if (!strcasecmp(argv[0],"sentinel")) {
/* argc == 1 is handled by main() as we need to enter the sentinel
* mode ASAP. */
@@ -666,6 +668,10 @@ void configSetCommand(redisClient *c) {
if (yn == -1) goto badfmt;
server.rdb_checksum = yn;
+ } else if (!strcasecmp(c->argv[2]->ptr,"slave-priority")) {
+ if (getLongLongFromObject(o,&ll) == REDIS_ERR ||
+ ll <= 0) goto badfmt;
+ server.slave_priority = ll;
} else {
addReplyErrorFormat(c,"Unsupported CONFIG parameter: %s",
(char*)c->argv[2]->ptr);
@@ -755,6 +761,7 @@ void configGetCommand(redisClient *c) {
config_get_numerical_field("repl-timeout",server.repl_timeout);
config_get_numerical_field("maxclients",server.maxclients);
config_get_numerical_field("watchdog-period",server.watchdog_period);
+ config_get_numerical_field("slave-priority",server.slave_priority);
/* Bool (yes/no) values */
config_get_bool_field("no-appendfsync-on-rewrite",
View
@@ -1160,6 +1160,7 @@ void initServerConfig() {
server.repl_serve_stale_data = 1;
server.repl_slave_ro = 1;
server.repl_down_since = time(NULL);
+ server.slave_priority = REDIS_DEFAULT_SLAVE_PRIORITY;
/* Client output buffer limits */
server.client_obuf_limits[REDIS_CLIENT_LIMIT_CLASS_NORMAL].hard_limit_bytes = 0;
@@ -2092,6 +2093,8 @@ sds genRedisInfoString(char *section) {
"master_link_down_since_seconds:%ld\r\n",
(long)server.unixtime-server.repl_down_since);
}
+ info = sdscatprintf(info,
+ "slave_priority:%d\r\n", server.slave_priority);
}
info = sdscatprintf(info,
"connected_slaves:%lu\r\n",
View
@@ -57,10 +57,9 @@
#define REDIS_SLOWLOG_MAX_LEN 128
#define REDIS_MAX_CLIENTS 10000
#define REDIS_AUTHPASS_MAX_LEN 512
-
+#define REDIS_DEFAULT_SLAVE_PRIORITY 100
#define REDIS_REPL_TIMEOUT 60
#define REDIS_REPL_PING_SLAVE_PERIOD 10
-
#define REDIS_RUN_ID_SIZE 40
#define REDIS_OPS_SEC_SAMPLES 16
@@ -694,6 +693,7 @@ struct redisServer {
int repl_serve_stale_data; /* Serve stale data when link is down? */
int repl_slave_ro; /* Slave is read only? */
time_t repl_down_since; /* Unix time at which link with master went down */
+ int slave_priority; /* Reported in INFO and used by Sentinel. */
/* Limits */
unsigned int maxclients; /* Max number of simultaneous clients */
unsigned long long maxmemory; /* Max number of memory bytes to use */

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