ceph-handler: use haproxy maintenance for rgw restarts

RGW currently restarts without waiting for existing connections to
close. By adjusting the HAProxy weight before the restart, we can
ensure that no active connections are disrupted during the restart
process.

Signed-off-by: Seena Fallah <seenafallah@gmail.com>

group_vars/all.yml.sample

@@ -420,6 +420,7 @@ dummy:
 # RGW handler checks
 #handler_health_rgw_check_retries: 5
 #handler_health_rgw_check_delay: 10
+#handler_rgw_use_haproxy_maintenance: false
 
 # NFS handler checks
 #handler_health_nfs_check_retries: 5

roles/ceph-defaults/defaults/main.yml

@@ -412,6 +412,7 @@ handler_health_mds_check_delay: 10
 # RGW handler checks
 handler_health_rgw_check_retries: 5
 handler_health_rgw_check_delay: 10
+handler_rgw_use_haproxy_maintenance: false
 
 # NFS handler checks
 handler_health_nfs_check_retries: 5

roles/ceph-handler/templates/restart_rgw_daemon.sh.j2

@@ -11,6 +11,7 @@ else
     RGW_PROTOCOL=http
 fi
 INSTANCES_NAME=({% for i in rgw_instances %}{{ i.instance_name }} {% endfor %})
+HAPROXY_BACKEND=({% for i in rgw_instances %}{{ i.haproxy_backend | default('rgw-backend') }} {% endfor %})
 RGW_IPS=({% for i in rgw_instances %}{{ i.radosgw_address }} {% endfor %})
 RGW_PORTS=({% for i in rgw_instances %}{{ i.radosgw_frontend_port }} {% endfor %})
 RGW_ZONE="{{ rgw_zone }}"
@@ -78,19 +79,38 @@ check_rest() {
 }
 
 for ((i=0; i<${RGW_NUMS}; i++)); do
-  # First, restart the daemon
-
   # Check if systemd unit exists
   # This is needed for new instances as the restart might trigger before the deployment
-  if systemctl list-units --full --all | grep -q "ceph-radosgw@rgw.${RGW_ZONE}.${HOST_NAME}.${INSTANCES_NAME[i]}"; then
-    systemctl restart ceph-radosgw@rgw.${RGW_ZONE}.${HOST_NAME}.${INSTANCES_NAME[i]}
-  else
+  if ! systemctl list-units --full --all | grep -q "ceph-radosgw@rgw.${RGW_ZONE}.${HOST_NAME}.${INSTANCES_NAME[i]}"; then
     echo "Systemd unit ceph-radosgw@rgw.${RGW_ZONE}.${HOST_NAME}.${INSTANCES_NAME[i]} does not exist."
     continue
   fi
 
+{% if handler_rgw_use_haproxy_maintenance %}
+  # set server weight to 0 on haproxy
+  echo "set weight ${HAPROXY_BACKEND[i]}/${INSTANCES_NAME[i]} 0" | socat stdio {{ haproxy_socket_path }}
+
+  # wait for the connections to drop
+  retries={{ handler_rgw_haproxy_maintenance_retries | default(60) }}
+  while [ $retries -gt 0 ]; do
+    if [ "$(echo "show servers conn ${HAPROXY_BACKEND[i]}" | socat stdio {{ haproxy_socket_path }} | grep "${HAPROXY_BACKEND[i]}/${INSTANCES_NAME[i]} " | awk '{ print $7 }')" -eq 0 ]; then
+      break
+    fi
+    sleep 1
+    let retries=retries-1
+  done
+{% endif %}
+
+  # Restart the daemon
+  systemctl restart ceph-radosgw@rgw.${RGW_ZONE}.${HOST_NAME}.${INSTANCES_NAME[i]}
+
   # Check socket files
   check_socket ${i}
   # Check rest
   check_rest ${i}
+
+{% if handler_rgw_use_haproxy_maintenance %}
+  # set server weight to 100 on haproxy
+  echo "set weight ${HAPROXY_BACKEND[i]}/${INSTANCES_NAME[i]} 100" | socat stdio {{ haproxy_socket_path }}
+{% endif %}
 done