Add test_explicit_timeline_creation_storcon and make it work (#11261)

Adds a basic test that makes the storcon issue explicit creation of a
timeline on safeekepers (main storcon PR in #11058). It was adapted from
`test_explicit_timeline_creation` from #11002.

Also, do a bunch of fixes needed to get the test work (the API
definitions weren't correct), and log more stuff when we can't create a
new timeline due to no safekeepers being active.

Part of #9011

---------

Co-authored-by: Arseny Sher <sher-ars@yandex.ru>

storage_controller/src/safekeeper_client.rs

@@ -1,6 +1,5 @@
 use safekeeper_api::models::{
     self, PullTimelineRequest, PullTimelineResponse, SafekeeperUtilization, TimelineCreateRequest,
-    TimelineStatus,
 };
 use safekeeper_client::mgmt_api::{Client, Result};
 use utils::id::{NodeId, TenantId, TimelineId};
@@ -60,7 +59,7 @@ impl SafekeeperClient {
     pub(crate) async fn create_timeline(
         &self,
         req: &TimelineCreateRequest,
-    ) -> Result<TimelineStatus> {
+    ) -> Result<reqwest::Response> {
         measured_request!(
             "create_timeline",
             crate::metrics::Method::Post,

storage_controller/src/service.rs

@@ -3804,7 +3804,7 @@ impl Service {
         create_mode: models::TimelineCreateRequestMode,
     ) -> Result<SafekeepersInfo, ApiError> {
         let timeline_id = timeline_info.timeline_id;
-        let pg_version = timeline_info.pg_version;
+        let pg_version = timeline_info.pg_version * 10000;
         // Initially start_lsn is determined by last_record_lsn in pageserver
         // response as it does initdb. However, later we persist it and in sk
         // creation calls replace with the value from the timeline row if it
@@ -8723,6 +8723,8 @@ impl Service {
     pub(crate) async fn safekeepers_for_new_timeline(
         &self,
     ) -> Result<Vec<SafekeeperInfo>, ApiError> {
+        // Number of safekeepers in different AZs we are looking for
+        let wanted_count = 3;
         let mut all_safekeepers = {
             let locked = self.inner.read().unwrap();
             locked
@@ -8768,15 +8770,17 @@ impl Service {
                 continue;
             }
             sks.push(sk_info.clone());
-            if sks.len() == 3 {
+            if sks.len() == wanted_count {
                 break;
             }
         }
-        if sks.len() == 3 {
+        if sks.len() == wanted_count {
             Ok(sks)
         } else {
             Err(ApiError::InternalServerError(anyhow::anyhow!(
-                "couldn't find three safekeepers in different AZs for new timeline"
+                "couldn't find {wanted_count} safekeepers in different AZs for new timeline (found: {}, total active: {})",
+                sks.len(),
+                all_safekeepers.len(),
             )))
         }
     }