diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 92a309cdd8c6a3c0437c06d87d8e31a42af9af57..0ff37e283d35f24e6417f902695e941da982c15e 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -105,6 +105,12 @@ variables:
   PL_SIM_COUNTRY_CODES:
     value: de hk
     description: "Which countries we want to plot live network, baseline and sim results for"
+  PL_PERFCLIENT_BANDWIDTH_UP:
+    value: ''
+    description: "If non-empty, override's onionperf node's bandwidth up. e.g. '1000000 kilobit'"
+  PL_PERFCLIENT_BANDWIDTH_DOWN:
+    value: ''
+    description: "If non-empty, override's onionperf node's bandwidth down. e.g. '1000000 kilobit'"
 stages:
   - build
   - stage-sim
@@ -712,6 +718,20 @@ tornettools-stage:
 
     - tornettools --seed $TRIAL_NUM generate jobs/network-data/relayinfo_staging_*.json jobs/network-data/userinfo_staging_*.json jobs/network-data/networkinfo_staging.gml jobs/network-data/tmodel --network_scale $SCALE --prefix $SIMDIR --tor jobs/opt/tor/bin/tor --torgencert jobs/opt/tor/bin/tor-gencert --process_scale $PROCESS_SCALE --load_scale $LOAD_SCALE
 
+    # Replace bandwidths
+    - 'python3 << EOM
+      config = open("$SIMDIR/shadow.config.yaml")\n\
+      import yaml\n\
+      config = yaml.load(config, yaml.loader.Loader)\n\
+      for (host, host_config) in config["hosts"].items():\n\
+        if host.startswith("perfclient"):\n\
+          if "$PL_PERFCLIENT_BANDWIDTH_UP":\n\
+            host_config["bandwidth_up"] = "$PL_PERFCLIENT_BANDWIDTH_UP"\n\
+          if "$PL_PERFCLIENT_BANDWIDTH_DOWN":\n\
+            host_config["bandwidth_down"] = "$PL_PERFCLIENT_BANDWIDTH_DOWN"\n\
+      yaml.dump(config, stream=open("$SIMDIR/shadow.config.yaml", "w"))\n\
+      EOM\n'
+
     # Run simulation
     - apt-get install -y libevent-2.1-7 libssl1.1 zlib1g libglib2.0-0 libigraph0v5 libprocps8 stow sysstat python3 python3-pip
     - pip3 install -r jobs/src/tornettools/requirements.txt