The following messages appears in logs (e.g. here and here) :

2018-08-02T01:44:05,980 | WARN  | paxweb-extender-1-thread-1 | ServletContainerInitializerScanner | 440 - org.ops4j.pax.web.pax-web-api - 6.0.9 | failed to parse and instantiate of javax.servlet.ServletContainerInitializer in classpath

My current understanding is that this is completely harmless; this message does NOT mean that all web related functionality (like /diagstatus and all RESTCONF URLs) is broken, it works - there are no real functional problems (related to this message).

It's just a possibly mildly confusing, and thus perhaps something to figure out how to supress, some time (low priority, given overall situation of things).

This WARN log also appears in older ODLPARENT-74 and ODLPARENT-82, but those used to contains full stack trace showing a RuntimeException from ASM as root cause of this message. That does not show up here - unclear whether that just got removed following a (Karaf / Pax Web) upgrade, or if this is something else. More likely the former, so this message is less scary now - but, in an ideal world, shouldn't show up at all.