diff --git a/swh/graph/cli.py b/swh/graph/cli.py
--- a/swh/graph/cli.py
+++ b/swh/graph/cli.py
@@ -1,9 +1,11 @@
-# Copyright (C) 2019-2020  The Software Heritage developers
+# Copyright (C) 2019-2022  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
+import logging
 from pathlib import Path
+import shlex
 from typing import TYPE_CHECKING, Any, Dict, Set, Tuple
 
 # WARNING: do not import unnecessary things here to keep cli startup time under
@@ -16,6 +18,8 @@
 if TYPE_CHECKING:
     from swh.graph.webgraph import CompressionStep  # noqa
 
+logger = logging.getLogger(__name__)
+
 
 class StepOption(click.ParamType):
     """click type for specifying a compression step on the CLI
@@ -171,13 +175,17 @@
     config = ctx.obj["config"]
     config.setdefault("graph", {})
     config["graph"]["path"] = graph
+
+    logger.debug("Building gPRC server command line")
     cmd, port = build_grpc_server_cmdline(**config["graph"])
 
     java_bin = cmd[0]
     if java_home is not None:
         java_bin = str(Path(java_home) / "bin" / java_bin)
 
-    print(f"Starting the GRPC server on 0.0.0.0:{port}")
+    # XXX: shlex.join() is in 3.8
+    # logger.info("Starting gRPC server: %s", shlex.join(cmd))
+    logger.info("Starting gRPC server: %s", " ".join(shlex.quote(x) for x in cmd))
     os.execvp(java_bin, cmd)
 
 
diff --git a/swh/graph/config.py b/swh/graph/config.py
--- a/swh/graph/config.py
+++ b/swh/graph/config.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2019  The Software Heritage developers
+# Copyright (C) 2019-2022  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
@@ -9,6 +9,8 @@
 
 import psutil
 
+logger = logging.getLogger(__name__)
+
 
 def find_graph_jar():
     """find swh-graph.jar, containing the Java part of swh-graph
@@ -17,6 +19,7 @@
     deployments who fecthed the JAR from pypi)
 
     """
+    logger.debug("Looking for swh-graph JAR")
     swh_graph_root = Path(__file__).parents[2]
     try_paths = [
         swh_graph_root / "java/target/",
@@ -24,13 +27,14 @@
         Path(sys.prefix) / "local/share/swh-graph/",
     ]
     for path in try_paths:
+        logger.debug("Looking for swh-graph JAR in %s", path)
         glob = list(path.glob("swh-graph-*.jar"))
         if glob:
             if len(glob) > 1:
-                logging.warning(
+                logger.warning(
                     "found multiple swh-graph JARs, " "arbitrarily picking one"
                 )
-            logging.info("using swh-graph JAR: {0}".format(glob[0]))
+            logger.info("using swh-graph JAR: {0}".format(glob[0]))
             return str(glob[0])
     raise RuntimeError("swh-graph JAR not found. Have you run `make java`?")
 
@@ -42,10 +46,13 @@
         # Use 0.1% of the RAM as a batch size:
         # ~1 billion for big servers, ~10 million for small desktop machines
         conf["batch_size"] = min(int(psutil.virtual_memory().total / 1000), 2**30 - 1)
+        logger.debug("batch_size not configured, defaulting to %s", conf["batch_size"])
     if "llp_gammas" not in conf:
         conf["llp_gammas"] = "-0,-1,-2,-3,-4"
+        logger.debug("llp_gammas not configured, defaulting to %s", conf["llp_gammas"])
     if "max_ram" not in conf:
         conf["max_ram"] = str(int(psutil.virtual_memory().total * 0.9))
+        logger.debug("max_ram not configured, defaulting to %s", conf["max_ram"])
     if "java_tool_options" not in conf:
         conf["java_tool_options"] = " ".join(
             [
@@ -59,6 +66,10 @@
                 "-XX:+ResizeTLAB",
             ]
         )
+        logger.debug(
+            "java_tool_options not providing, defaulting to %s",
+            conf["java_tool_options"],
+        )
     conf["java_tool_options"] = conf["java_tool_options"].format(
         max_ram=conf["max_ram"]
     )
diff --git a/swh/graph/grpc_server.py b/swh/graph/grpc_server.py
--- a/swh/graph/grpc_server.py
+++ b/swh/graph/grpc_server.py
@@ -16,12 +16,17 @@
 
 from swh.graph.config import check_config
 
+logger = logging.getLogger(__name__)
+
 
 def build_grpc_server_cmdline(**config):
     port = config.pop("port", None)
     if port is None:
         port = aiohttp.test_utils.unused_port()
+        logger.debug("Port not configured, using random port %s", port)
+    logger.debug("Checking configuration and populating default values")
     config = check_config(config)
+    logger.debug("Configuration: %r", config)
     cmd = [
         "java",
         "--class-path",
@@ -39,8 +44,8 @@
     cmd, port = build_grpc_server_cmdline(**config)
     print(cmd)
     # XXX: shlex.join() is in 3.8
-    # logging.info("Starting RPC server: %s", shlex.join(cmd))
-    logging.info("Starting GRPC server: %s", " ".join(shlex.quote(x) for x in cmd))
+    # logger.info("Starting gRPC server: %s", shlex.join(cmd))
+    logger.info("Starting gRPC server: %s", " ".join(shlex.quote(x) for x in cmd))
     server = subprocess.Popen(cmd)
     return server, port
 
@@ -50,5 +55,5 @@
     try:
         server.wait(timeout=timeout)
     except subprocess.TimeoutExpired:
-        logging.warning("Server did not terminate, sending kill signal...")
+        logger.warning("Server did not terminate, sending kill signal...")
         server.kill()