[nexus] Auto-update schema on boot (#9030)

Fixes #8912

Should be merged after the rest of Nexus quiesce/handoff is complete.

Author: smklein

smf/nexus/multi-sled/config-partial.toml

@@ -18,11 +18,10 @@ mode = "file"
 path = "/dev/stdout"
 if_exists = "append"
 
-# TODO: Uncomment the following lines to enable automatic schema
-# migration on boot.
-#
-# [schema]
-# schema_dir = "/var/nexus/schema/crdb"
+# This allows Nexus to see the CRDB schema, and apply schema updates when it
+# boots.
+[schema]
+schema_dir = "/var/nexus/schema/crdb"
 
 [background_tasks]
 dns_internal.period_secs_config = 60

smf/nexus/single-sled/config-partial.toml

@@ -18,11 +18,10 @@ mode = "file"
 path = "/dev/stdout"
 if_exists = "append"
 
-# TODO: Uncomment the following lines to enable automatic schema
-# migration on boot.
-#
-# [schema]
-# schema_dir = "/var/nexus/schema/crdb"
+# This allows Nexus to see the CRDB schema, and apply schema updates when it
+# boots.
+[schema]
+schema_dir = "/var/nexus/schema/crdb"
 
 [background_tasks]
 dns_internal.period_secs_config = 60