added defaults

promtail/promtail-config.yml

@@ -6,7 +6,7 @@ positions:
   filename: /tmp/positions.yaml
 
 clients:
-  - url: http://${LOKI_HOST}:3100/loki/api/v1/push
+  - url: http://${LOKI_HOST:-loki}:3100/loki/api/v1/push
 
 scrape_configs:
   - job_name: flog_scrape

telegraf/telegraf.conf

@@ -80,7 +80,7 @@
   ## Multiple URLs can be specified for a single cluster, only ONE of the
   ## urls will be written to each interval.
   ##   ex: urls = ["https://us-west-2-1.aws.cloud2.influxdata.com"]
-  urls = ["http://${INFLUX_HOST}:8086"]
+  urls = ["http://${INFLUX_HOST:-influxdb}:8086"]
 
   ## Token for authentication.
   token = "$INFLUX_WRITE_TOKEN"