Deprecate max pipeline per indexer (#4754)

* Changed the default of `default_merge_concurrency` to `2 * num_cpus / 3`

We have a observed at least one case (rather extreme however) where the
default settings did not make it possible for merging to keep up with
indexing.

* Added documentation for indexer's cpu_capacity

Closes #4716

* This PR deprecates the max_num_pipeline_per_index in Kafka's source
config.

It also renames desired_num_pipelines into num_pipelines.

Closes #4624

config/tutorials/gh-archive/kafka-source.yaml

@@ -1,8 +1,7 @@
-version: 0.7
+version: 0.8
 source_id: kafka-source
 source_type: kafka
-max_num_pipelines_per_indexer: 1
-desired_num_pipelines: 2
+num_pipelines: 2
 params:
   topic: gh-archive
   client_params:

docs/configuration/source-config.md

@@ -80,11 +80,10 @@ Short max poll interval durations may cause a source to crash when back pressure
 
 ```bash
 cat << EOF > source-config.yaml
-version: 0.7
+version: 0.8
 source_id: my-kafka-source
 source_type: kafka
-max_num_pipelines_per_indexer: 1
-desired_num_pipelines: 2
+num_pipelines: 2
 params:
   topic: my-topic
   client_params:
@@ -164,38 +163,13 @@ EOF
 ./quickwit source create --index my-index --source-config source-config.yaml
 ```
 
-## Maximum number of pipelines per indexer
-
-The `max_num_pipelines_per_indexer` parameter is only available for sources that can be distributed: Kafka, GCP PubSub and Pulsar(coming soon).
-
-The maximum number of indexing pipelines defines the limit of pipelines spawned for the source on a given indexer.
-This maximum can be reached only if there are enough `desired_num_pipelines` to run.
-
-:::note
-
-With the following parameters, only one pipeline will run on one indexer.
-
-- `max_num_pipelines_per_indexer=2`
-- `desired_num_pipelines=1`
-
-:::
-
-## Desired number of pipelines
-
-`desired_num_pipelines` parameter is only available for sources that can be distributed: Kafka, GCP PubSub and Pulsar (coming soon).
-
-The desired number of indexing pipelines defines the number of pipelines to run on a cluster for the source. It is a "desired"
-number as it cannot be reach it there is not enough indexers in
-the cluster.
-
-:::note
-
-With the following parameters, only one pipeline will start on the sole indexer.
+## Number of pipelines
 
-- `max_num_pipelines_per_indexer=1`
-- `desired_num_pipelines=2`
+`num_pipelines` parameter is only available for sources that can be distributed: Kafka, GCP PubSub and Pulsar (coming soon).
 
-:::
+It defines the number of pipelines to run on a cluster for the source. The actual placement of these pipelines on the different indexer
+will be decided by the control plane. Note that distributions of a source like Kafka is done by assigning a set of partitions to different pipelines.
+As a result, it is recommended to make sure the number of partitions is a multiple of the number of `num_pipelines`.
 
 ## Transform parameters
 

docs/ingest-data/kafka.md

@@ -101,11 +101,10 @@ This tutorial assumes that the Kafka cluster is available locally on the default
 #
 # Kafka source config file.
 #
-version: 0.7
+version: 0.8
 source_id: kafka-source
 source_type: kafka
-max_num_pipelines_per_indexer: 1
-desired_num_pipelines: 2
+num_pipelines: 2
 params:
   topic: gh-archive
   client_params:

quickwit/quickwit-cli/src/source.rs

@@ -741,8 +741,7 @@ mod tests {
             .collect();
         let sources = vec![SourceConfig {
             source_id: "foo-source".to_string(),
-            desired_num_pipelines: NonZeroUsize::new(1).unwrap(),
-            max_num_pipelines_per_indexer: NonZeroUsize::new(1).unwrap(),
+            num_pipelines: NonZeroUsize::new(1).unwrap(),
             enabled: true,
             source_params: SourceParams::file("path/to/file"),
             transform_config: None,
@@ -802,17 +801,15 @@ mod tests {
         let sources = [
             SourceConfig {
                 source_id: "foo-source".to_string(),
-                desired_num_pipelines: NonZeroUsize::new(1).unwrap(),
-                max_num_pipelines_per_indexer: NonZeroUsize::new(1).unwrap(),
+                num_pipelines: NonZeroUsize::new(1).unwrap(),
                 enabled: true,
                 source_params: SourceParams::stdin(),
                 transform_config: None,
                 input_format: SourceInputFormat::Json,
             },
             SourceConfig {
                 source_id: "bar-source".to_string(),
-                desired_num_pipelines: NonZeroUsize::new(1).unwrap(),
-                max_num_pipelines_per_indexer: NonZeroUsize::new(1).unwrap(),
+                num_pipelines: NonZeroUsize::new(1).unwrap(),
                 enabled: true,
                 source_params: SourceParams::stdin(),
                 transform_config: None,

quickwit/quickwit-cli/src/tool.rs

@@ -422,8 +422,7 @@ pub async fn local_ingest_docs_cli(args: LocalIngestDocsArgs) -> anyhow::Result<
         .map(|vrl_script| TransformConfig::new(vrl_script, None));
     let source_config = SourceConfig {
         source_id: CLI_SOURCE_ID.to_string(),
-        max_num_pipelines_per_indexer: NonZeroUsize::new(1).expect("1 is always non-zero."),
-        desired_num_pipelines: NonZeroUsize::new(1).expect("1 is always non-zero."),
+        num_pipelines: NonZeroUsize::new(1).expect("1 is always non-zero."),
         enabled: true,
         source_params,
         transform_config,
@@ -608,8 +607,7 @@ pub async fn merge_cli(args: MergeArgs) -> anyhow::Result<()> {
             index_id: args.index_id,
             source_config: SourceConfig {
                 source_id: args.source_id,
-                max_num_pipelines_per_indexer: NonZeroUsize::new(1).unwrap(),
-                desired_num_pipelines: NonZeroUsize::new(1).unwrap(),
+                num_pipelines: NonZeroUsize::new(1).unwrap(),
                 enabled: true,
                 source_params: SourceParams::Vec(VecSourceParams::default()),
                 transform_config: None,

quickwit/quickwit-config/resources/tests/source_config/kafka-source.json

@@ -2,7 +2,6 @@
     "version": "0.7",
     "source_id": "hdfs-logs-kafka-source",
     "desired_num_pipelines": 2,
-    "max_num_pipelines_per_indexer": 2,
     "source_type": "kafka",
     "params": {
         "topic": "cloudera-cluster-logs",

quickwit/quickwit-config/src/lib.rs

@@ -72,7 +72,7 @@ pub use crate::node_config::{
     enable_ingest_v2, IndexerConfig, IngestApiConfig, JaegerConfig, NodeConfig, SearcherConfig,
     SplitCacheLimits, DEFAULT_QW_CONFIG_PATH,
 };
-use crate::source_config::serialize::{SourceConfigV0_7, VersionedSourceConfig};
+use crate::source_config::serialize::{SourceConfigV0_7, SourceConfigV0_8, VersionedSourceConfig};
 pub use crate::storage_config::{
     AzureStorageConfig, FileStorageConfig, GoogleCloudStorageConfig, RamStorageConfig,
     S3StorageConfig, StorageBackend, StorageBackendFlavor, StorageConfig, StorageConfigs,
@@ -88,6 +88,7 @@ pub use crate::storage_config::{
     DocMapping,
     VersionedSourceConfig,
     SourceConfigV0_7,
+    SourceConfigV0_8,
     VersionedIndexConfig,
     IndexConfigV0_7,
     VersionedIndexTemplate,