diff --git a/README.md b/README.md
index a6e7b7a..561141a 100644
--- a/README.md
+++ b/README.md
@@ -219,8 +219,11 @@ Since it is currently a work-in-progress project, we are frequently adding new o
 
 You can also use [docker image](https://hub.docker.com/r/jqtype/rpxy) instead of directly executing the binary. There are only two docker-specific environment variables.
 
+- `HOST_USER` (default: `user`): User name executing `rpxy` inside the container.
+- `HOST_UID` (default: `900`): `UID` of `HOST_USER`.
+- `HOST_GID` (default: `900`): `GID` of `HOST_USER`
 - `LOG_LEVEL=debug|info|warn|error`: Log level
-- `LOG_TO_FILE=true|false`: Enable logging to the log file `/var/log/rpxy/rpxy.log` using `logrotate`. You should mount `/var/log/rpxy` via docker volume option if enabled.
+- `LOG_TO_FILE=true|false`: Enable logging to the log file `/rpxy/log/rpxy.log` using `logrotate`. You should mount `/rpxy/log` via docker volume option if enabled. The log dir and file will be owned by the `HOST_USER` with `HOST_UID:HOST_GID` on the host machine. Hence, `HOST_USER`, `HOST_UID` and `HOST_GID` should be the same as ones of the user who executes the `rpxy` docker container on the host.
 
 Other than them, all you need is to mount your `config.toml` as `/etc/rpxy.toml` and certificates/private keys as you like through the docker volume option. See [`docker/docker-compose.yml`](./docker/docker-compose.yml) for the detailed configuration. Note that the file path of keys and certificates must be ones in your docker container.