Sysmon is running and logs the following every 60s:

ERROR:root:Caught exception while flushing: Value out of range: 18446744073708923780
DEBUG:chromite.scripts.sysmon.loop:Sleeping for 60, 60 remaining
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/bytes" was given value "1054646628046", which is not greater than or equal to "18446744073390688551".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/packets" was given value "730094743", which is not greater than or equal to "18446744073707625010".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/errors" was given value "16", which is not greater than or equal to "3674".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/dropped" was given value "27591", which is not greater than or equal to "31249".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/bytes" was given value "281768347485", which is not greater than or equal to "169444408534752".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/packets" was given value "188422656", which is not greater than or equal to "116123680134".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/errors" was given value "0", which is not greater than or equal to "336".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/dropped" was given value "5929", which is not greater than or equal to "6265".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/bytes" was given value "274411060845", which is not greater than or equal to "180959037188894".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/packets" was given value "184361013", which is not greater than or equal to "122731205963".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/errors" was given value "16", which is not greater than or equal to "1732".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/dropped" was given value "12136", which is not greater than or equal to "13852".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/bytes" was given value "303572857788", which is not greater than or equal to "188877688382112".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/packets" was given value "204789571", which is not greater than or equal to "132083329493".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/errors" was given value "0", which is not greater than or equal to "1539".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/dropped" was given value "3437", which is not greater than or equal to "4976".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/bytes" was given value "254397753694", which is not greater than or equal to "164099941376445".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/packets" was given value "192197797", which is not greater than or equal to "114251758186".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/errors" was given value "0", which is not greater than or equal to "67".
WARNING:chromite.scripts.sysmon.net_metrics:Monotonically increasing metric "dev/net/dropped" was given value "6089", which is not greater than or equal to "6156".

Attempting a sysmon restart.

Looks like the metric is populated now.