Document disableCompaction defaulting when using thanos sidecar (#7127)

* docs: disableCompaction defaulting when using thanos sidecar

For the Prometheus CRD, the operator default to true for
`spec.disableCompaction` when `spec.thanos.objectStorageConfig(|File)`
is defined, but this is not documented anywhere but in code (and in
kube-prometheus-stack helm chart values, as it turns out).


---------

Signed-off-by: Max Gautier <mg@max.gautier.name>

Documentation/api.md

@@ -3161,7 +3161,9 @@ bool
 </em>
 </td>
 <td>
-<p>When true, the Prometheus compaction is disabled.</p>
+<p>When true, the Prometheus compaction is disabled.
+When <code>spec.thanos.objectStorageConfig</code> or <code>spec.objectStorageConfigFile</code> are defined, the operator automatically
+disables block compaction to avoid race conditions during block uploads (as the Thanos documentation recommends).</p>
 </td>
 </tr>
 <tr>
@@ -13032,7 +13034,9 @@ bool
 </em>
 </td>
 <td>
-<p>When true, the Prometheus compaction is disabled.</p>
+<p>When true, the Prometheus compaction is disabled.
+When <code>spec.thanos.objectStorageConfig</code> or <code>spec.objectStorageConfigFile</code> are defined, the operator automatically
+disables block compaction to avoid race conditions during block uploads (as the Thanos documentation recommends).</p>
 </td>
 </tr>
 <tr>

bundle.yaml

@@ -35231,7 +35231,10 @@ spec:
                   type: object
                 type: array
               disableCompaction:
-                description: When true, the Prometheus compaction is disabled.
+                description: |-
+                  When true, the Prometheus compaction is disabled.
+                  When `spec.thanos.objectStorageConfig` or `spec.objectStorageConfigFile` are defined, the operator automatically
+                  disables block compaction to avoid race conditions during block uploads (as the Thanos documentation recommends).
                 type: boolean
               dnsConfig:
                 description: Defines the DNS configuration for the pods.

example/prometheus-operator-crd-full/monitoring.coreos.com_prometheuses.yaml

@@ -3523,7 +3523,10 @@ spec:
                   type: object
                 type: array
               disableCompaction:
-                description: When true, the Prometheus compaction is disabled.
+                description: |-
+                  When true, the Prometheus compaction is disabled.
+                  When `spec.thanos.objectStorageConfig` or `spec.objectStorageConfigFile` are defined, the operator automatically
+                  disables block compaction to avoid race conditions during block uploads (as the Thanos documentation recommends).
                 type: boolean
               dnsConfig:
                 description: Defines the DNS configuration for the pods.

example/prometheus-operator-crd/monitoring.coreos.com_prometheuses.yaml

@@ -3524,7 +3524,10 @@ spec:
                   type: object
                 type: array
               disableCompaction:
-                description: When true, the Prometheus compaction is disabled.
+                description: |-
+                  When true, the Prometheus compaction is disabled.
+                  When `spec.thanos.objectStorageConfig` or `spec.objectStorageConfigFile` are defined, the operator automatically
+                  disables block compaction to avoid race conditions during block uploads (as the Thanos documentation recommends).
                 type: boolean
               dnsConfig:
                 description: Defines the DNS configuration for the pods.

jsonnet/prometheus-operator/prometheuses-crd.json

@@ -3044,7 +3044,7 @@
                     "type": "array"
                   },
                   "disableCompaction": {
-                    "description": "When true, the Prometheus compaction is disabled.",
+                    "description": "When true, the Prometheus compaction is disabled.\nWhen `spec.thanos.objectStorageConfig` or `spec.objectStorageConfigFile` are defined, the operator automatically\ndisables block compaction to avoid race conditions during block uploads (as the Thanos documentation recommends).",
                     "type": "boolean"
                   },
                   "dnsConfig": {

pkg/apis/monitoring/v1/prometheus_types.go

@@ -992,6 +992,8 @@ type PrometheusSpec struct {
 	RetentionSize ByteSize `json:"retentionSize,omitempty"`
 
 	// When true, the Prometheus compaction is disabled.
+	// When `spec.thanos.objectStorageConfig` or `spec.objectStorageConfigFile` are defined, the operator automatically
+	// disables block compaction to avoid race conditions during block uploads (as the Thanos documentation recommends).
 	DisableCompaction bool `json:"disableCompaction,omitempty"`
 
 	// Defines the configuration of the Prometheus rules' engine.