Following an upgrade from 4.9.x to 5.0.0 on MX and LX appliances the engine_st_parser will fail to start.

The following messages are found in the /var/log/sys.log:
Nov  2 15:16:37 logapp MTASK: %LOGLOGIC-4 module:mtask(8504);  file:service.c(svcStart,87);  action:starting service /loglogic/bin/engine_st_parser ;
Nov  2 15:16:37 logapp MTASK: %LOGLOGIC-3 module:mtask(8504);  file:service.c(service_monitor,505);  action:ERROR: /loglogic/bin/engine_st_parser(8728) does not exist - restarting ;
Nov  2 15:16:37 logapp MTASK: %LOGLOGIC-3 module:mtask(8504);  file:service.c(service_monitor,510);  action:ERROR: Failed to access /loglogic/bin/engine_st_parser - disableing service ;

All further mtask operations on the engine also fail. This is because engine_st_parser no longer exists in version 5.0 and higher. In addition, some engine names have been modified. Here is a list of the modifications.

Lastly, the engine_st_parser binary was actually removed from /loglogic/bin/ in LMI 5.0 and higher. ST's are unaffected by the st_parser issue because they have neither engine_st_parser nor engine_lx_parser.

To ensure the proper node_config.xml is being used we can obtain its checksum:
$ md5sum /loglogic/conf/node_config.xml
Then we compare with a known good system. Below is the proper checksum and filesize:

Logapp root:/loglogic/conf 0$ md5sum node_config.xml
0270f0298f17fd29f497fa563a2ebe79  node_config.xml

-rw-r--r-- 1 root root 33K Oct  7 11:09 node_config.xml

Use the procedure in the resolution section below to institute the proper node_config.xml file.
 

This article explains why engine_st_parser fails to start after upgrading to LMI 5.x.

Only affects MX and LX appliances

In this case the node_config.xml file was not update\replaced during the upgrade. To use the correct one perform the following:

$ mtask stop
$ mv /loglogic/conf/node_config.xml /loglogic/conf/node_config.xml.old
scp or copy/paste a known good node_config.xml onto appliance and ensure permissions are correct based on those listed above.
$ mtask start