diff --git a/README.md b/README.md
index fc4ac999..8aadcc23 100644
--- a/README.md
+++ b/README.md
@@ -119,6 +119,7 @@ PyHSS uses a queued microservices model. Each service performs a specific set of
 
 The following services make up PyHSS:
  - diameterService.py: Handles receiving and sending of diameter messages, and diameter client connection state.
+ - gsupService.py: Handles receiving and sending of GSUP messages to interact with 2G/3G Osmocom components.
  - hssService.py: Provides decoding and encoding of diameter requests and responses, as well as logic to perform as a HSS.
  - apiService.py: Provides the API, to allow management of PyHSS.
  - georedService.py: Sends georaphic redundancy messages to geored peers when defined. Also handles webhook messages.
diff --git a/debian/pyhss.install b/debian/pyhss.install
index 7c7b805c..d5b990e5 100644
--- a/debian/pyhss.install
+++ b/debian/pyhss.install
@@ -3,6 +3,7 @@
 # * pyhss_geored.service: disabled in the default config
 # * pyhss_log.service: using systemd's journal instead
 # * pyhss.service: meta-service making assumptions about what services are used
+/systemd/pyhss_api.service /lib/systemd/system/
 /systemd/pyhss_diameter.service /lib/systemd/system/
 /systemd/pyhss_gsup.service /lib/systemd/system/
 /systemd/pyhss_hss.service /lib/systemd/system/
diff --git a/systemd/pyhss.service b/systemd/pyhss.service
index 1b6d02a8..98542ff1 100644
--- a/systemd/pyhss.service
+++ b/systemd/pyhss.service
@@ -1,3 +1,7 @@
+# Legacy meta-service with possibly outdated assumptions on which database
+# (mysql, default is now sqlite and postgres is also supported) and services
+# (log and geored are typically not needed) are being used. Consider running
+# individual services that you actually want to have in your setup instead.
 [Unit]
 Description=PyHSS
 After=network-online.target mysql.service
diff --git a/systemd/pyhss_api.service b/systemd/pyhss_api.service
index ab930466..fac8be2c 100644
--- a/systemd/pyhss_api.service
+++ b/systemd/pyhss_api.service
@@ -1,6 +1,9 @@
+# Optional HTTP server providing an API for managing PyHSS.
 [Unit]
 Description=PyHSS API Service
 After=network.target
+Requires=pyhss_hss.service
+After=pyhss_hss.service
 
 [Service]
 Environment="PYTHONUNBUFFERED=1"
diff --git a/systemd/pyhss_database.service b/systemd/pyhss_database.service
index 32eb2960..2e5a8cc1 100644
--- a/systemd/pyhss_database.service
+++ b/systemd/pyhss_database.service
@@ -1,3 +1,5 @@
+# Optional legacy service that may get removed in the future:
+# https://github.com/nickvsnetworking/pyhss/issues/264
 [Unit]
 Description=PyHSS Database Service
 PartOf=pyhss.service
diff --git a/systemd/pyhss_diameter.service b/systemd/pyhss_diameter.service
index c01c73d4..895c5c07 100644
--- a/systemd/pyhss_diameter.service
+++ b/systemd/pyhss_diameter.service
@@ -1,6 +1,10 @@
+# Handling of receiving and sending of diameter messages, and diameter client
+# connection state.
 [Unit]
 Description=PyHSS Diameter Service
 PartOf=pyhss.service
+Requires=pyhss_hss.service
+After=pyhss_hss.service
 
 [Service]
 Environment="PYTHONUNBUFFERED=1"
diff --git a/systemd/pyhss_geored.service b/systemd/pyhss_geored.service
index 9bd9994f..10b683a7 100644
--- a/systemd/pyhss_geored.service
+++ b/systemd/pyhss_geored.service
@@ -1,3 +1,5 @@
+# Optional geographic redundancy service that may get removed in the future:
+# https://github.com/nickvsnetworking/pyhss/issues/334
 [Unit]
 Description=PyHSS Geored Service
 PartOf=pyhss.service
diff --git a/systemd/pyhss_gsup.service b/systemd/pyhss_gsup.service
index d1b76ea1..7ba9e4c8 100644
--- a/systemd/pyhss_gsup.service
+++ b/systemd/pyhss_gsup.service
@@ -1,6 +1,9 @@
+# Optional GSUP message handler for interacting with 2G/3G Osmocom components.
 [Unit]
 Description=PyHSS GSUP Service
 PartOf=pyhss.service
+Requires=pyhss_hss.service
+After=pyhss_hss.service
 
 [Service]
 Environment="PYTHONUNBUFFERED=1"
diff --git a/systemd/pyhss_hss.service b/systemd/pyhss_hss.service
index b6285b19..c5f252fa 100644
--- a/systemd/pyhss_hss.service
+++ b/systemd/pyhss_hss.service
@@ -1,6 +1,11 @@
+# The main PyHSS service: Initializes the database, provides decoding and
+# encoding of diameter requests and responses, as well as logic to perform as a
+# HSS.
 [Unit]
 Description=PyHSS HSS Service
 PartOf=pyhss.service
+Requires=redis-server.service
+After=redis-server.service
 
 [Service]
 Environment="PYTHONUNBUFFERED=1"
diff --git a/systemd/pyhss_log.service b/systemd/pyhss_log.service
index 263f2a69..49d87aad 100644
--- a/systemd/pyhss_log.service
+++ b/systemd/pyhss_log.service
@@ -1,3 +1,5 @@
+# Optional service for writing to log files. Consider reading logs through
+# journalctl instead.
 [Unit]
 Description=PyHSS Log Service
 PartOf=pyhss.service
diff --git a/systemd/pyhss_metric.service b/systemd/pyhss_metric.service
index ca89e968..c9583f96 100644
--- a/systemd/pyhss_metric.service
+++ b/systemd/pyhss_metric.service
@@ -1,6 +1,9 @@
+# Optional service for exposing prometheus metrics.
 [Unit]
 Description=PyHSS Metric Service
 PartOf=pyhss.service
+Requires=pyhss_hss.service
+After=pyhss_hss.service
 
 [Service]
 Environment="PYTHONUNBUFFERED=1"