Upstream the availability zone info string from KeyDB

src/config.c

@@ -3100,6 +3100,7 @@ standardConfig static_configs[] = {
     /* SDS Configs */
     createSDSConfig("primaryauth", "masterauth", MODIFIABLE_CONFIG | SENSITIVE_CONFIG, EMPTY_STRING_IS_NULL, server.primary_auth, NULL, NULL, NULL),
     createSDSConfig("requirepass", NULL, MODIFIABLE_CONFIG | SENSITIVE_CONFIG, EMPTY_STRING_IS_NULL, server.requirepass, NULL, NULL, updateRequirePass),
+    createSDSConfig("availability-zone", NULL, MODIFIABLE_CONFIG, 0, server.sdsAvailabilityZone, "", NULL, NULL),
 
     /* Enum Configs */
     createEnumConfig("supervised", NULL, IMMUTABLE_CONFIG, supervised_mode_enum, server.supervised_mode, SUPERVISED_NONE, NULL, NULL),

src/server.c

@@ -5381,7 +5381,8 @@ sds genValkeyInfoString(dict *section_dict, int all_sections, int everything) {
             "lru_clock:%u\r\n", server.lruclock,
             "executable:%s\r\n", server.executable ? server.executable : "",
             "config_file:%s\r\n", server.configfile ? server.configfile : "",
-            "io_threads_active:%i\r\n", server.io_threads_active));
+            "io_threads_active:%i\r\n", server.io_threads_active,
+            "availability_zone:%s\r\n", server.sdsAvailabilityZone));
         /* clang-format on */
 
         /* Conditional properties */

src/server.h

@@ -2121,6 +2121,7 @@ struct valkeyServer {
                                                 is down, doesn't affect pubsub global. */
     long reply_buffer_peak_reset_time; /* The amount of time (in milliseconds) to wait between reply buffer peak resets */
     int reply_buffer_resizing_enabled; /* Is reply buffer resizing enabled (1 by default) */
+    sds sdsAvailabilityZone;    /* When run in a cloud environment we can configure the availability zone it is running in */
     /* Local environment */
     char *locale_collate;
 };

valkey.conf

@@ -2319,3 +2319,9 @@ jemalloc-bg-thread yes
 # to suppress
 #
 # ignore-warnings ARM64-COW-BUG
+
+# Inform Valkey of the availability zone if running in a cloud environment.  Currently
+# this is only exposed via the info command for clients to use, but in the future we
+# we may also use this when making decisions for replication.
+#
+# availability-zone "us-east-1a"