storcon_cli: remove old tenant-scatter command (#8127)

## Problem

This command was used in the very early days of sharding, before the
storage controller had anti-affinity + scheduling optimization to spread
out shards.

## Summary of changes

- Remove `storcon_cli tenant-scatter`

control_plane/storcon_cli/src/main.rs

@@ -1,5 +1,5 @@
 use futures::StreamExt;
-use std::{collections::HashMap, str::FromStr, time::Duration};
+use std::{str::FromStr, time::Duration};
 
 use clap::{Parser, Subcommand};
 use pageserver_api::{
@@ -21,7 +21,7 @@ use utils::id::{NodeId, TenantId};
 
 use pageserver_api::controller_api::{
     NodeConfigureRequest, NodeRegisterRequest, NodeSchedulingPolicy, PlacementPolicy,
-    TenantLocateResponse, TenantShardMigrateRequest, TenantShardMigrateResponse,
+    TenantShardMigrateRequest, TenantShardMigrateResponse,
 };
 
 #[derive(Subcommand, Debug)]
@@ -110,12 +110,6 @@ enum Command {
         #[arg(long)]
         config: String,
     },
-    /// Attempt to balance the locations for a tenant across pageservers.  This is a client-side
-    /// alternative to the storage controller's scheduling optimization behavior.
-    TenantScatter {
-        #[arg(long)]
-        tenant_id: TenantId,
-    },
     /// Print details about a particular tenant, including all its shards' states.
     TenantDescribe {
         #[arg(long)]
@@ -498,88 +492,6 @@ async fn main() -> anyhow::Result<()> {
                 })
                 .await?;
         }
-        Command::TenantScatter { tenant_id } => {
-            // Find the shards
-            let locate_response = storcon_client
-                .dispatch::<(), TenantLocateResponse>(
-                    Method::GET,
-                    format!("control/v1/tenant/{tenant_id}/locate"),
-                    None,
-                )
-                .await?;
-            let shards = locate_response.shards;
-
-            let mut node_to_shards: HashMap<NodeId, Vec<TenantShardId>> = HashMap::new();
-            let shard_count = shards.len();
-            for s in shards {
-                let entry = node_to_shards.entry(s.node_id).or_default();
-                entry.push(s.shard_id);
-            }
-
-            // Load list of available nodes
-            let nodes_resp = storcon_client
-                .dispatch::<(), Vec<NodeDescribeResponse>>(
-                    Method::GET,
-                    "control/v1/node".to_string(),
-                    None,
-                )
-                .await?;
-
-            for node in nodes_resp {
-                if matches!(node.availability, NodeAvailabilityWrapper::Active) {
-                    node_to_shards.entry(node.id).or_default();
-                }
-            }
-
-            let max_shard_per_node = shard_count / node_to_shards.len();
-
-            loop {
-                let mut migrate_shard = None;
-                for shards in node_to_shards.values_mut() {
-                    if shards.len() > max_shard_per_node {
-                        // Pick the emptiest
-                        migrate_shard = Some(shards.pop().unwrap());
-                    }
-                }
-                let Some(migrate_shard) = migrate_shard else {
-                    break;
-                };
-
-                // Pick the emptiest node to migrate to
-                let mut destinations = node_to_shards
-                    .iter()
-                    .map(|(k, v)| (k, v.len()))
-                    .collect::<Vec<_>>();
-                destinations.sort_by_key(|i| i.1);
-                let (destination_node, destination_count) = *destinations.first().unwrap();
-                if destination_count + 1 > max_shard_per_node {
-                    // Even the emptiest destination doesn't have space: we're done
-                    break;
-                }
-                let destination_node = *destination_node;
-
-                node_to_shards
-                    .get_mut(&destination_node)
-                    .unwrap()
-                    .push(migrate_shard);
-
-                println!("Migrate {} -> {} ...", migrate_shard, destination_node);
-
-                storcon_client
-                    .dispatch::<TenantShardMigrateRequest, TenantShardMigrateResponse>(
-                        Method::PUT,
-                        format!("control/v1/tenant/{migrate_shard}/migrate"),
-                        Some(TenantShardMigrateRequest {
-                            tenant_shard_id: migrate_shard,
-                            node_id: destination_node,
-                        }),
-                    )
-                    .await?;
-                println!("Migrate {} -> {} OK", migrate_shard, destination_node);
-            }
-
-            // Spread the shards across the nodes
-        }
         Command::TenantDescribe { tenant_id } => {
             let describe_response = storcon_client
                 .dispatch::<(), TenantDescribeResponse>(