1. Clickhouse service restart

sudo service clickhouse-server start

2. Error message

Start clickhouse-server service: Poco::Exception. Code: 1000, e.code() = 0, 
e.displayText() = Exception: Failed to merge config with '/etc/clickhouse-server/config.d/metric_log.xml': 
Exception: Root element doesn't have the corresponding root element as the config file. 
It must be <yandex> (version 21.3.4.25 (official build))
Cannot obtain value of path from config file: /etc/clickhouse-server/config.xml

3. Problem analysis

Exception starting Clickhouse server service. Unable to merge configuration with ‘/ etc/Clickhouse server/config’. The root element does not have a corresponding root element as a configuration file. It must be (version 21.3.4.25 (official version)). The path value cannot be obtained from the configuration file:/etc/Clickhouse server/config.xml

translated as/etc/Clickhouse server/config d/metric_log. The content in the XML configuration file, XML, cannot be parsed correctly. The official version is 21.3 4.25 it is required that the content of the configuration file should be in the label

4. Solutions

# open files /etc/clickhouse-server/config.d/metric_log.xml
vi /etc/clickhouse-server/config.d/metric_log.xml

# Mofdify the content of metric_log.xml file
<clickhouse>
    <metric_log>
        <database>system</database>
        <table>metric_log</table>
        <flush_interval_milliseconds>7500</flush_interval_milliseconds>
        <collect_interval_milliseconds>1000</collect_interval_milliseconds>
    </metric_log>
</clickhouse>
# Modify the file content and put it in <yandex> tag
# Contents of the modified metric_log.xml file
<yandex>
	<clickhouse>
	    <metric_log>
	        <database>system</database>
	        <table>metric_log</table>
	        <flush_interval_milliseconds>7500</flush_interval_milliseconds>
	        <collect_interval_milliseconds>1000</collect_interval_milliseconds>
	    </metric_log>
	</clickhouse>
</yandex>

# save and restart
sudo service clickhouse-server start
# Prompt after execution
Start clickhouse-server service: Path to data directory in /etc/clickhouse-server/config.xml: /data/clickhouse/
DONE