ClickHouse/tests/testflows/kerberos/configs/clickhouse/config.d/ssl.xml

<clickhouse>
    <openSSL>
        <server>
            <certificateFile>/etc/clickhouse-server/ssl/server.crt</certificateFile>
            <privateKeyFile>/etc/clickhouse-server/ssl/server.key</privateKeyFile>
            <verificationMode>none</verificationMode>
            <cacheSessions>true</cacheSessions>
        </server>
        <client>
            <cacheSessions>true</cacheSessions>
            <verificationMode>none</verificationMode>
            <invalidCertificateHandler>
                <name>AcceptCertificateHandler</name>
            </invalidCertificateHandler>
        </client>
    </openSSL>
</clickhouse>