feat(charts/cozystack): add recommended sysctl and etcd defaults

Add recommended sysctl parameters for TCP orphan handling, network backlog,
and TCP keepalive to improve DRBD connection stability and prevent port exhaustion.

Add etcd quota and request size limits to prevent etcd running out of space
with large LINSTOR CRD datasets and allow larger CRD objects to be stored.

Signed-off-by: ohotnikov.ivan <ohotnikov.ivan@e-queo.net>

Author: ohotnikov.ivan

charts/cozystack/templates/_helpers.tpl

@@ -29,6 +29,17 @@ machine:
     net.ipv4.neigh.default.gc_thresh1: "4096"
     net.ipv4.neigh.default.gc_thresh2: "8192"
     net.ipv4.neigh.default.gc_thresh3: "16384"
+    # TCP orphan handling
+    net.ipv4.tcp_orphan_retries: "3"
+    net.ipv4.tcp_fin_timeout: "30"
+    # Network backlog
+    net.core.netdev_max_backlog: "5000"
+    net.core.netdev_budget: "600"
+    net.core.netdev_budget_usecs: "8000"
+    # TCP keepalive (early detection of dead connections)
+    net.ipv4.tcp_keepalive_time: "600"
+    net.ipv4.tcp_keepalive_intvl: "10"
+    net.ipv4.tcp_keepalive_probes: "6"
   kernel:
     modules:
     - name: openvswitch
@@ -120,6 +131,9 @@ cluster:
   etcd:
     advertisedSubnets:
       {{- toYaml .Values.advertisedSubnets | nindent 6 }}
+    extraArgs:
+      quota-backend-bytes: "8589934592"  # 8GiB - prevent etcd running out of space with large LINSTOR CRD datasets
+      max-request-bytes: "10485760"      # 10MiB - allow larger CRD objects to be stored
   {{- end }}
 {{- end }}