diff --git a/scripts/http_host/host_manager.py b/scripts/http_host/host_manager.py
index b22d941..624ed81 100755
--- a/scripts/http_host/host_manager.py
+++ b/scripts/http_host/host_manager.py
@@ -19,11 +19,12 @@ from http_host_lib.utils import assert_linux, assert_single_process, assert_sudo
 def cli():
     """
     Manages OpenFreeMap HTTP hosts, including:\n
-    - Downloading tilesets\n
-    - Downloading assets\n
     - Deploying the correct versions of tilesets\n
+    - Downloading assets\n
+    - Downloading tilesets\n
     - Mounting directories\n
     - Updating nginx config\n
+    - Running the sync cron task every minute
     """
 
 
@@ -66,7 +67,7 @@ def download_tileset(area: str, version: str, list_versions: bool, runs_dir: Pat
         runs_dir = DEFAULT_RUNS_DIR
 
     if not runs_dir.parent.exists():
-        sys.exit("run dir's parent doesn't exist")
+        sys.exit("runs dir's parent doesn't exist")
 
     return download_and_extract_tileset(area, selected_version, runs_dir)
 
@@ -155,21 +156,21 @@ def sync(ctx):
     """
     print(datetime.datetime.now(tz=datetime.timezone.utc))
 
-    downloaded = False
-    downloaded += ctx.invoke(download_tileset, area='monaco')
-    # d2 = ctx.invoke(download_tileset, area='planet')
-    if downloaded:
+    assert_single_process()
+
+    download_done = False
+    download_done += ctx.invoke(download_tileset, area='monaco')
+    download_done += ctx.invoke(download_tileset, area='planet')
+    if download_done:
         ctx.invoke(mount)
 
     ctx.invoke(download_assets)
 
-    deployed = ctx.invoke(deploy_tileset_version)
+    deploy_done = ctx.invoke(deploy_tileset_version)
 
-    if downloaded or deployed:
+    if download_done or deploy_done:
         ctx.invoke(nginx_sync)
 
 
 if __name__ == '__main__':
-    # TODO
-    assert_single_process()
     cli()
diff --git a/scripts/http_host/http_host_lib/nginx.py b/scripts/http_host/http_host_lib/nginx.py
index 48b064e..43c7e05 100644
--- a/scripts/http_host/http_host_lib/nginx.py
+++ b/scripts/http_host/http_host_lib/nginx.py
@@ -20,14 +20,14 @@ def write_nginx_config():
 
         run_dir = DEFAULT_RUNS_DIR / area / version
         if not run_dir.is_dir():
-            print(f"{run_dir} doesn't exists, skipping")
+            print(f"  {run_dir} doesn't exists, skipping")
             continue
 
         tilejson_path = run_dir / 'tilejson-tiles-org.json'
 
         metadata_path = subdir / 'metadata.json'
         if not metadata_path.is_file():
-            print(f"{metadata_path} doesn't exists, skipping")
+            print(f"  {metadata_path} doesn't exists, skipping")
             continue
 
         url_prefix = f'https://tiles.openfreemap.org/{area}/{version}'
@@ -44,7 +44,7 @@ def write_nginx_config():
             check=True,
         )
 
-        # TODO raise the expires times once things are stable
+        # TODO # target 10y
         version_str = f"""
             location /{area}/{version} {{    # no trailing hash
                 alias {tilejson_path};       # no trailing hash
diff --git a/scripts/http_host/http_host_lib/utils.py b/scripts/http_host/http_host_lib/utils.py
index 7eefc7c..cb6d987 100644
--- a/scripts/http_host/http_host_lib/utils.py
+++ b/scripts/http_host/http_host_lib/utils.py
@@ -1,6 +1,7 @@
 import os
 import subprocess
 import sys
+import time
 from pathlib import Path
 
 import requests
@@ -16,9 +17,11 @@ def assert_linux():
         sys.exit('Needs to be run on Linux')
 
 
-# TODO
 def assert_single_process():
-    pass
+    p = subprocess.run(['pgrep', '-fl', sys.argv[0]], capture_output=True, text=True)
+    lines = [l for l in p.stdout.splitlines() if 'python' in l]
+    if len(lines) >= 2:
+        sys.exit('Detected multiple processes, terminating')
 
 
 def download_if_size_differs(url: str, local_file: Path) -> bool:
diff --git a/scripts/http_host/metadata_to_tilejson.py b/scripts/http_host/metadata_to_tilejson.py
index caa0177..1e63195 100755
--- a/scripts/http_host/metadata_to_tilejson.py
+++ b/scripts/http_host/metadata_to_tilejson.py
@@ -32,7 +32,7 @@ def cli(metadata_path: Path, tilejson_path: Path, url_prefix: str, minify: bool)
 
     ''
     tilejson['vector_layers'] = metadata_json_key.pop('vector_layers')
-    assert not metadata_json_key  # check that no more keys left
+    assert not metadata_json_key  # check that no more keys are left
 
     tilejson['attribution'] = metadata.pop('attribution')
     tilejson['bounds'] = [float(n) for n in metadata.pop('bounds').split(',')]
diff --git a/ssh_lib/pkg_base.py b/ssh_lib/pkg_base.py
index 4b7e02c..a59e447 100644
--- a/ssh_lib/pkg_base.py
+++ b/ssh_lib/pkg_base.py
@@ -17,6 +17,7 @@ def pkg_base(c):
         'rsync',
         'unzip',
         'wget',
+        'psmisc',
         #
         'btrfs-progs',
         #