Comment 2 for bug 1928347

[Root Cause]
When peer is selected, the script launched the minor alarm
"NTP cannot reach external time source; syncing with peer controller only."
But the major alarm "NTP configuration does not contain any valid or reachable NTP servers."
is not launched once this minor alarm is on.
And peer selected flag is not cleared once peer is selected but later peer is unreachable.
As a result, this minor alarm is not cleared after peer is unreachable and major alarm is not launched.

[Overview Design]
In the bug LP:1889101, we decided to remove minor alarm
"NTP cannot reach external time source; syncing with peer controller only."
because NTP does not prioritize external time source over peer.

Expected behavior with the patch for LP:1889101 are:
When no NTP server is reachable: major alarm "NTP configuration does not contain any valid or reachable NTP servers."
When peer is selected with reliable upstream NTP server: No major alarm.
When outer server is unreachable: minor alarm "NTP address [server ip] is not a valid or a reachable NTP server."

According to revised spec with the patch for LP:1889101, it will fix this issue because the minor alarm is removed and there is no peer flag is used in alarm activate in code.