Check locations
Multi-location checks with consensus
Where a check runs from decides what it can tell you. One machine failing to reach you is not an outage.
Per monitor
Which location saw what
Every check records the location that made it, so a monitor can say it is reachable from Frankfurt and not from New York rather than averaging the two into a shrug.
The fleet
The probe fleet
Checks run from separate providers on separate autonomous systems, so that two of our machines cannot share one network's bad day. Every address is published at /ips.json, as a file you can paste into a firewall rule.
Marked points are the machines that run checks. The arcs are checks leaving them for targets elsewhere, not places we check from.
Consensus
Consensus between locations
Independent networks, not just distant cities
Two servers three thousand kilometres apart at the same provider share that provider's routing, peering and bad afternoons. Geographically they look independent; operationally they are one machine with extra latency.
PingFleet picks locations for network independence first: different hosting companies, different autonomous systems. Distance is the tie-breaker, not the criterion.
Every address is published at /ips.json and /ips.txt, as a file, because the person adding them to a firewall wants a list they can paste into a script.
Agreement before anyone is paged
A monitor is called down when a majority of the locations that reported agree. A single bad route no longer pages anybody.
A location that has never reported is not counted as a vote against, and a vote older than a few intervals stops counting.
The third state
The degraded state
Reachable from Frankfurt, not from New York, named on the monitor. It does not page anybody at three in the morning; it is not hidden either.
Before reporting a partial failure, PingFleet checks whether that location is failing the same way for everybody. If it is, the problem is ours, and you are not told your service is degraded because one of our machines is having a bad hour.
Questions
- Can I choose the locations?
- On paid plans, yes: either let PingFleet spread them for maximum independence, or pick them explicitly.
- How many locations do I get?
- 1 on the free plan, 2 on Plus and 3 on Pro. Where there is more than one, they have to agree before a monitor is called down.
- What happens if a location is retired?
- The account is moved to the nearest equivalent and told, because a move shifts the latency baseline and an unexplained step in a graph reads as your infrastructure slowing down.