The /server_discovery_and_monitoring/monitoring/heartbeat/pooled/dns test currently fails and/or is flaky. This test was initially observed as problematic when transitioning from RHEL7 to RHEL8 for s390x zSeries builds (CDRIVER-3923). At that time, the failure was isolated to the call to getaddrinfo () blocking for 5 seconds on RHEL8. The test was later observed to fail in a similar way on another build variant (arm64 w/ Ubuntu 18.04).

The test is currently being skipped, so to work on it, it will first be necessary to remove it from .evergreen/skip-tests.txt and run a patch build to determine the current failure mode(s).

It will also be worth considering removing the implementation of test_framework_skip_if_rhel8_zseries () in src/libmongoc/tests/test-libmongoc.c.