[8.7] Fix desired balance spec (#93617) (#95474)

Backports #93617 to 8.7

* Spec relied on a presence of a node with `test-cluster-0` name.
  This change reads the name from the cluster state instead.

Co-authored-by: Ievgen Degtiarenko <[email protected]>

Author: arteam

qa/smoke-test-multinode/src/yamlRestTest/resources/rest-api-spec/test/smoke_test_multinode/30_desired_balance.yml

@@ -71,6 +71,11 @@ setup:
       version: " - 8.6.99"
       reason: "Field added in in 8.7.0"
 
+  - do:
+      cluster.state: {}
+  - set: { nodes._arbitrary_key_ : node_id }
+  - set: { nodes.$node_id.name : node_name }
+
   - do:
       _internal.get_desired_balance: { }
 
@@ -101,8 +106,8 @@ setup:
   - is_true: 'cluster_balance_stats.tiers.data_content.actual_disk_usage.average'
   - is_true: 'cluster_balance_stats.tiers.data_content.actual_disk_usage.std_dev'
   - is_true: 'cluster_balance_stats.nodes'
-  - is_true: 'cluster_balance_stats.nodes.test-cluster-0'
-  - gte: { 'cluster_balance_stats.nodes.test-cluster-0.shard_count' : 0 }
-  - gte: { 'cluster_balance_stats.nodes.test-cluster-0.forecast_write_load': 0.0 }
-  - gte: { 'cluster_balance_stats.nodes.test-cluster-0.forecast_disk_usage_bytes' : 0 }
-  - gte: { 'cluster_balance_stats.nodes.test-cluster-0.actual_disk_usage_bytes' : 0 }
+  - is_true: 'cluster_balance_stats.nodes.$node_name'
+  - gte: { 'cluster_balance_stats.nodes.$node_name.shard_count' : 0 }
+  - gte: { 'cluster_balance_stats.nodes.$node_name.forecast_write_load': 0.0 }
+  - gte: { 'cluster_balance_stats.nodes.$node_name.forecast_disk_usage_bytes' : 0 }
+  - gte: { 'cluster_balance_stats.nodes.$node_name.actual_disk_usage_bytes' : 0 }

rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/cluster.desired_balance/10_basic.yml

@@ -26,6 +26,11 @@ setup:
       version: " - 8.6.99"
       reason: "Field added in in 8.7.0"
 
+  - do:
+      cluster.state: {}
+  - set: { nodes._arbitrary_key_ : node_id }
+  - set: { nodes.$node_id.name : node_name }
+
   - do:
       _internal.get_desired_balance: { }
 
@@ -56,11 +61,11 @@ setup:
   - is_true: 'cluster_balance_stats.tiers.data_content.actual_disk_usage.average'
   - is_true: 'cluster_balance_stats.tiers.data_content.actual_disk_usage.std_dev'
   - is_true: 'cluster_balance_stats.nodes'
-  - is_true: 'cluster_balance_stats.nodes.test-cluster-0'
-  - gte: { 'cluster_balance_stats.nodes.test-cluster-0.shard_count' : 0 }
-  - gte: { 'cluster_balance_stats.nodes.test-cluster-0.forecast_write_load': 0.0 }
-  - gte: { 'cluster_balance_stats.nodes.test-cluster-0.forecast_disk_usage_bytes' : 0 }
-  - gte: { 'cluster_balance_stats.nodes.test-cluster-0.actual_disk_usage_bytes' : 0 }
+  - is_true: 'cluster_balance_stats.nodes.$node_name'
+  - gte: { 'cluster_balance_stats.nodes.$node_name.shard_count' : 0 }
+  - gte: { 'cluster_balance_stats.nodes.$node_name.forecast_write_load': 0.0 }
+  - gte: { 'cluster_balance_stats.nodes.$node_name.forecast_disk_usage_bytes' : 0 }
+  - gte: { 'cluster_balance_stats.nodes.$node_name.actual_disk_usage_bytes' : 0 }
 
 ---
 "Test get desired balance for single shard":