Add Telegraf SSL support

Change-Id: Ic00f217a981d9d9724415faf0c06d1ad48f58745
PROD-related: PROD-28066
diff --git a/docker/swarm/stack/monitoring/prometheus/init.yml b/docker/swarm/stack/monitoring/prometheus/init.yml
index 65dd5b9..d7db52c 100644
--- a/docker/swarm/stack/monitoring/prometheus/init.yml
+++ b/docker/swarm/stack/monitoring/prometheus/init.yml
@@ -32,6 +32,7 @@
               volumes:
                 - ${prometheus:server:dir:config}:${_param:prometheus_server_config_directory}
                 - ${prometheus:server:dir:data}:${_param:prometheus_server_data_directory}
+                - /etc/ssl/certs/ca-certificates.crt:/etc/ssl/certs/ca-certificates.crt:ro
               environment:
                 PROMETHEUS_CONFIG_DIR: ${_param:prometheus_server_config_directory}
                 PROMETHEUS_DATA_DIR: ${_param:prometheus_server_data_directory}