enable layer eviction by default in prod (#3933)

Leave disk_usage_based_eviction above the current max usage in prod
(82%ish), so that deploying this commit won't trigger
disk_usage_based_eviction.

As indicated in the TODO, we'll decrease the value to 80% later.

Also update the staging YAMLs to use the anchor syntax for
`evictions_low_residence_duration_metric_threshold` like we do in the
prod YAMLs as of this patch.

.github/ansible/prod.ap-southeast-1.hosts.yaml

@@ -8,6 +8,16 @@ storage:
       pg_distrib_dir: /usr/local
       metric_collection_endpoint: http://neon-internal-api.aws.neon.tech/billing/api/v1/usage_events
       metric_collection_interval: 10min
+      disk_usage_based_eviction:
+        max_usage_pct: 85 # TODO: decrease to 80 after all pageservers are below 80
+        min_avail_bytes: 0
+        period: "10s"
+      tenant_config:
+        eviction_policy:
+          kind: "LayerAccessThreshold"
+          period: "10m"
+          threshold: &default_eviction_threshold "24h"
+      evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
       remote_storage:
         bucket_name: "{{ bucket_name }}"
         bucket_region: "{{ bucket_region }}"

.github/ansible/prod.eu-central-1.hosts.yaml

@@ -8,6 +8,16 @@ storage:
       pg_distrib_dir: /usr/local
       metric_collection_endpoint: http://neon-internal-api.aws.neon.tech/billing/api/v1/usage_events
       metric_collection_interval: 10min
+      disk_usage_based_eviction:
+        max_usage_pct: 85 # TODO: decrease to 80 after all pageservers are below 80
+        min_avail_bytes: 0
+        period: "10s"
+      tenant_config:
+        eviction_policy:
+          kind: "LayerAccessThreshold"
+          period: "10m"
+          threshold: &default_eviction_threshold "24h"
+      evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
       remote_storage:
         bucket_name: "{{ bucket_name }}"
         bucket_region: "{{ bucket_region }}"

.github/ansible/prod.us-east-2.hosts.yaml

@@ -8,6 +8,16 @@ storage:
       pg_distrib_dir: /usr/local
       metric_collection_endpoint: http://neon-internal-api.aws.neon.tech/billing/api/v1/usage_events
       metric_collection_interval: 10min
+      disk_usage_based_eviction:
+        max_usage_pct: 85 # TODO: decrease to 80 after all pageservers are below 80
+        min_avail_bytes: 0
+        period: "10s"
+      tenant_config:
+        eviction_policy:
+          kind: "LayerAccessThreshold"
+          period: "10m"
+          threshold: &default_eviction_threshold "24h"
+      evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
       remote_storage:
         bucket_name: "{{ bucket_name }}"
         bucket_region: "{{ bucket_region }}"

.github/ansible/prod.us-west-2.hosts.yaml

@@ -8,6 +8,16 @@ storage:
       pg_distrib_dir: /usr/local
       metric_collection_endpoint: http://neon-internal-api.aws.neon.tech/billing/api/v1/usage_events
       metric_collection_interval: 10min
+      disk_usage_based_eviction:
+        max_usage_pct: 85 # TODO: decrease to 80 after all pageservers are below 80
+        min_avail_bytes: 0
+        period: "10s"
+      tenant_config:
+        eviction_policy:
+          kind: "LayerAccessThreshold"
+          period: "10m"
+          threshold: &default_eviction_threshold "24h"
+      evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
       remote_storage:
         bucket_name: "{{ bucket_name }}"
         bucket_region: "{{ bucket_region }}"

.github/ansible/staging.eu-west-1.hosts.yaml

@@ -8,20 +8,16 @@ storage:
       pg_distrib_dir: /usr/local
       metric_collection_endpoint: http://neon-internal-api.aws.neon.build/billing/api/v1/usage_events
       metric_collection_interval: 10min
-      evictions_low_residence_duration_metric_threshold: "20m"
       disk_usage_based_eviction:
         max_usage_pct: 80
-        # TODO: learn typical resident-size growth rate [GiB/minute] and configure
-        # min_avail_bytes such that we have X minutes of headroom.
         min_avail_bytes: 0
-        # We assume that the worst-case growth rate is small enough that we can
-        # catch above-threshold conditions by checking every 10s.
         period: "10s"
       tenant_config:
         eviction_policy:
           kind: "LayerAccessThreshold"
           period: "20m"
-          threshold: "20m"
+          threshold: &default_eviction_threshold "20m"
+      evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
       remote_storage:
         bucket_name: "{{ bucket_name }}"
         bucket_region: "{{ bucket_region }}"

.github/ansible/staging.us-east-2.hosts.yaml

@@ -8,20 +8,16 @@ storage:
       pg_distrib_dir: /usr/local
       metric_collection_endpoint: http://neon-internal-api.aws.neon.build/billing/api/v1/usage_events
       metric_collection_interval: 10min
-      evictions_low_residence_duration_metric_threshold: "20m"
       disk_usage_based_eviction:
         max_usage_pct: 80
-        # TODO: learn typical resident-size growth rate [GiB/minute] and configure
-        # min_avail_bytes such that we have X minutes of headroom.
         min_avail_bytes: 0
-        # We assume that the worst-case growth rate is small enough that we can
-        # catch above-threshold conditions by checking every 10s.
         period: "10s"
       tenant_config:
         eviction_policy:
           kind: "LayerAccessThreshold"
           period: "20m"
-          threshold: "20m"
+          threshold: &default_eviction_threshold "20m"
+      evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
       remote_storage:
         bucket_name: "{{ bucket_name }}"
         bucket_region: "{{ bucket_region }}"