The server is Ubuntu 18.04 and I installed that via apt. The apachectl command says it is using MPM.
# apachectl status
Apache Server Status for localhost (via ::1)
Server Version: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.1
Server MPM: prefork
Server Built: 2020-03-13T12:26:16
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Current Time: Friday, 10-Jul-2020 21:00:16 +0430
Restart Time: Friday, 10-Jul-2020 15:10:54 +0430
Parent Server Config. Generation: 1
Parent Server MPM Generation: 0
Server uptime: 5 hours 49 minutes 22 seconds
Server load: 1.81 2.09 2.14
Total accesses: 287766 - Total Traffic: 63.6 GB
CPU Usage: u376.8 s74.98 cu0 cs0 - 2.16% CPU load
13.7 requests/sec - 3.1 MB/second - 231.7 kB/request
62 requests currently being processed, 28 idle workers
WRK._WKKKRWRKR_W_WR_RRWWC.K___WKW____K__W__WR_K_WRR_WRWKKRR_WKKR
W..RK_K_R__RR.WW.KW._.R.R...K._W.._W.K.._..W........C.._........
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Scoreboard Key:
"_" Waiting for Connection, "S" Starting up, "R" Reading Request,
"W" Sending Reply, "K" Keepalive (read), "D" DNS Lookup,
"C" Closing connection, "L" Logging, "G" Gracefully finishing,
"I" Idle cleanup of worker, "." Open slot with no current process
>Did you see this syntax error?
Regarding that error, the following line in not commented
DefaultRuntimeDir ${APACHE_RUN_DIR}
I don't remember that I have intentionally uncommentted that. What is the default setting then?