The 'restart' option of the init script cannot restart CH if it was not able to shutdown in `shutdown_wait_unfinished` seconds.
```
# sudo /etc/init.d/clickhouse-server restart
/var/run/clickhouse-server/clickhouse-server.pid file exists and contains pid = 14388.
The process with pid = 14388 is running.
Sent terminate signal to process with pid 14388.
Waiting for server to stop
/var/run/clickhouse-server/clickhouse-server.pid file exists and contains pid = 14388.
The process with pid = 14388 is running.
Waiting for server to stop
...
/var/run/clickhouse-server/clickhouse-server.pid file exists and contains pid = 14388.
Waiting for server to stop
/var/run/clickhouse-server/clickhouse-server.pid file exists and contains pid = 14388.
Waiting for server to stop
...
/var/run/clickhouse-server/clickhouse-server.pid file exists and contains pid = 14388.
Will terminate forcefully.
Code: 425, e.displayText() = DB::ErrnoException: Cannot send kill signal, errno: 3, strerror: No such process (version 21.1.3.32 (official build))
```
The log:
```
2021.02.08 18:57:23.999226 [ 14388 ] {} <Information> Application: Closed connections. But 3 remain. Tip: To increase wait time add to config: <shutdown_wait_unfinished>60</shutdown_wait_unfinished>
2021.02.08 18:57:24.016684 [ 14388 ] {} <Information> Application: Will shutdown forcefully.
2021.02.08 18:58:28.478835 [ 23658 ] {} <Information> Application: Will watch for the process with pid 23659
2021.02.08 18:58:28.478962 [ 23659 ] {} <Information> Application: Forked a child process to watch
2021.02.08 18:58:28.479067 [ 23659 ] {} <Information> StatusFile: Status file /var/run/clickhouse-server/clickhouse-server.pid already exists - unclean restart. Contents: 14388
2021.02.08 18:58:28.479147 [ 23659 ] {} <Information> SentryWriter: Sending crash reports is disabled
2021.02.08 18:58:28.479183 [ 23659 ] {} <Trace> Pipe: Pipe capacity is 1.00 MiB
2021.02.08 18:58:28.532977 [ 23659 ] {} <Information> : Starting ClickHouse 21.1.3.32 with revision 54445, build id: 63BC1671E8C217170F9B6C6346099FD1F76E784F, PID 23659
2021.02.08 18:58:28.533059 [ 23659 ] {} <Information> Application: starting up
```

*
          * The second is important for Docker and systemd-nspawn.
          * When the container has no capabilities,
          * but the executable file inside the container has capabilities,
          *  then attempt to run this file will end up with a cryptic "Operation not permitted" message.
          */
#if defined(__linux__)
        fmt::print("Setting capabilities for clickhouse binary. This is optional.\n");
        std::string command = fmt::format("command -v setcap >/dev/null"
            " && echo > {0} && chmod a+x {0} && {0} && setcap 'cap_net_admin,cap_ipc_lock,cap_sys_nice+ep' {0} && {0} && rm {0}"
            " && setcap 'cap_net_admin,cap_ipc_lock,cap_sys_nice+ep' {1}"
            " || echo \"Cannot set 'net_admin' or 'ipc_lock' or 'sys_nice' capability for clickhouse binary."
                " This is optional. Taskstats accounting will be disabled."
                " To enable taskstats accounting you may add the required capability later manually.\"",
            "/tmp/test_setcap.sh", fs::canonical(main_bin_path).string());
        executeScript(command);
#endif
        
        if (is_interactive && has_password_for_default_user)
        {
            if (ask("Allow server to accept connections from the network (default is localhost only), [y/N]: "))
            {
                std::string listen_file = config_d / "listen.xml";
                WriteBufferFromFile out(listen_file);
                out << "<yandex>\n"
                    "    <listen_host>::</listen_host>\n"
                    "</yandex>\n";
                out.sync();
                out.finalize();
                fmt::print("The choice is saved in file {}.\n", listen_file);