**Describe the bug**
`SYSTEM KILL` does not shutdown the server when run in a docker environment. I used https://hub.docker.com/r/yandex/clickhouse-server/ instructions to setup the docker.

**How to reproduce**
* ClickHouse server version 20.12.4 revision 54442.
```
myrotk@altinity-qa-cosmic3:~$ docker pull yandex/clickhouse-server
Using default tag: latest
latest: Pulling from yandex/clickhouse-server
da7391352a9b: Pull complete
14428a6d4bcd: Pull complete
2c2d948710f2: Pull complete
076cd2c6a81e: Pull complete
201ea6cda8c8: Pull complete
0d7b4e598027: Pull complete
0d86a58e3639: Pull complete
3b78a4fd0f92: Pull complete
86d65487f611: Pull complete
dc82dea7d6fe: Pull complete
Digest: sha256:8f669dafd35eb527210cc77973ed927734dff2c2cafd345823c8c99769124fd1
Status: Downloaded newer image for yandex/clickhouse-server:latest
docker.io/yandex/clickhouse-server:latest

myrotk@altinity-qa-cosmic3:~$ docker run -d --name some-clickhouse-server --ulimit nofile=262144:262144 yandex/clickhouse-server
35603911ec6c5737f069a019a60d03270cefe78e52c77d1bc6ff33a0548ae97e

myrotk@altinity-qa-cosmic3:~$ docker run -it --rm --link some-clickhouse-server:clickhouse-server yandex/clickhouse-client --host clickhouse-server
Unable to find image 'yandex/clickhouse-client:latest' locally
latest: Pulling from yandex/clickhouse-client
f22ccc0b8772: Pull complete
3cf8fb62ba5f: Pull complete
e80c964ece6a: Pull complete
6f064a173914: Pull complete
37a06aaf9ee5: Pull complete
Digest: sha256:504e18bed5162a20bbff6071ca1b7c7baca1380d2e2755e4d6bf4bac7e534531
Status: Downloaded newer image for yandex/clickhouse-client:latest
ClickHouse client version 20.12.4.5 (official build).
Connecting to clickhouse-server:9000 as user default.
Connected to ClickHouse server version 20.12.4 revision 54442.

35603911ec6c :) SYSTEM KILL

SYSTEM KILL

Query id: 0da8cfef-36c8-4de9-8c12-3e9175c5aed0

Ok.

0 rows in set. Elapsed: 0.002 sec.

35603911ec6c :)



В Graphite компоненты пути(папки) разделяются точкой.
     У нас принят путь формата root_path.hostname_yandex_ru.key
     root_path по умолчанию one_min
     key - лучше гру" или "meminfo.free", "meminfo.total"
    template <class T>
    void writeToGraphite(const std::string & key, const T & value, const std::string & config_name = DEFAULT_GRAPHITE_CONFIG_NAME, time_t timestamp = 0, const std::string & custom_root_path = "")
    {
        auto writer = getGraphiteWriter(config_name);
        if (writer)
            writer->write(key, value, timestamp, custom_root_path);
    }
    template <class T>
    void writeToGraphite(const GraphiteWriter::KeyValueVector<T> & key_vals, const std::string & config_name = DEFAULT_GRAPHITE_CONFIG_NAME, time_t timestamp = 0, const std::string & custom_root_path = "")
    {
        auto writer = getGraphiteWriter(config_name);
        if (writer)
            writer->write(key_vals, timestamp, custom_root_path);
    }
    template <class T>
    void writeToGraphite(const GraphiteWriter::KeyValueVector<T> & key_vals, const std::chrono::system_clock::time_point & current_time, const std::string & custom_root_path)
    {
        auto writer = getGraphiteWriter();
        if (writer)
            writer->write(key_vals, std::chrono::system_clock::to_time_t(current_time), custom_root_path);
    }
    GraphiteWriter * getGraphiteWriter(const std::string & config_name = DEFAULT_GRAPHITE_CONFIG_NAME)