diff --git a/scripts/docker/command/docker_run_install.sh b/scripts/docker/command/docker_run_install.sh
index c5c2fa0..fb8a69a 100755
--- a/scripts/docker/command/docker_run_install.sh
+++ b/scripts/docker/command/docker_run_install.sh
@@ -1,6 +1,17 @@
 #!/bin/bash
 
-dockerCommandRunInstallUser() 
+# Run a command as the unprivileged rootless Docker install user.
+#
+# This used to ssh to <user>@localhost to get a fully-initialised user session
+# (so `systemctl --user` and the rootless dockerd would work). That needs an SSH
+# server, a generated key and authorized_keys — none of which the install set
+# up, so the whole rootless path silently no-op'd. Instead run via `sudo -u`
+# with the session env set explicitly: `loginctl enable-linger` (done during
+# rootless setup) keeps the user's `systemd --user` and /run/user/<uid> alive,
+# so `systemctl --user` works, and DOCKER_HOST points at the rootless socket.
+# `sudo -u` to an unprivileged user is not a root escalation, and there's no SSH
+# attack surface.
+dockerCommandRunInstallUser()
 {
     local silent_flag=""
     if [ "$1" == "--silent" ]; then
@@ -9,35 +20,25 @@ dockerCommandRunInstallUser()
     fi
     local remote_command="$1"
 
-    # Get the value of PasswordAuthentication from sshd_config
-    local result=$(sudo sed -i '/#PasswordAuthentication/d' $sshd_config)
-    local passwordAuth=$(grep -i "^PasswordAuthentication" $sshd_config | awk '{print $2}')
-
-    # Keys
-    local private_path="${ssh_dir}private/"
-    local install_user_key="${CFG_INSTALL_NAME}_sshkey_${CFG_DOCKER_INSTALL_USER}"
-
-    # Run the SSH command using the existing SSH variables
-    local output
-    if [ "$passwordAuth" == "no" ]; then
-        if [ -z "$silent_flag" ]; then
-            ssh -i "${private_path}${install_user_key}" -o StrictHostKeyChecking=no "$CFG_DOCKER_INSTALL_USER@localhost" "$remote_command"
-        else
-            ssh -i "${private_path}${install_user_key}" -o StrictHostKeyChecking=no "$CFG_DOCKER_INSTALL_USER@localhost" "$remote_command" > /dev/null 2>&1
-        fi
-    else
-        if [ -z "$silent_flag" ]; then
-            sshpass -p "$CFG_DOCKER_INSTALL_PASS" ssh -o StrictHostKeyChecking=no "$CFG_DOCKER_INSTALL_USER@localhost" "$remote_command"
-        else
-            sshpass -p "$CFG_DOCKER_INSTALL_PASS" ssh -o StrictHostKeyChecking=no "$CFG_DOCKER_INSTALL_USER@localhost" "$remote_command" > /dev/null 2>&1
-        fi
+    local uid
+    uid=$(id -u "$CFG_DOCKER_INSTALL_USER" 2>/dev/null)
+    if [ -z "$uid" ]; then
+        isError "Cannot run as '$CFG_DOCKER_INSTALL_USER' — user does not exist."
+        return 1
     fi
 
-    local exit_code=$?
+    # rootless docker installs its binaries to the user's ~/bin, so include it.
+    local run_env=(
+        "HOME=/home/$CFG_DOCKER_INSTALL_USER"
+        "XDG_RUNTIME_DIR=/run/user/$uid"
+        "DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$uid/bus"
+        "DOCKER_HOST=unix:///run/user/$uid/docker.sock"
+        "PATH=/home/$CFG_DOCKER_INSTALL_USER/bin:/usr/bin:/bin:/usr/local/bin"
+    )
 
-    if [ $exit_code -eq 0 ]; then
-        :
+    if [ -n "$silent_flag" ]; then
+        sudo -u "$CFG_DOCKER_INSTALL_USER" env "${run_env[@]}" bash -c "$remote_command" >/dev/null 2>&1
     else
-        :
+        sudo -u "$CFG_DOCKER_INSTALL_USER" env "${run_env[@]}" bash -c "$remote_command"
     fi
 }