112 lines
3.9 KiB
HTML
112 lines
3.9 KiB
HTML
|
<head>
|
||
|
|
<title>Nicholas Orlowsky</title>
|
||
|
|
<link rel="stylesheet" href="/style.css">
|
||
|
|
<link rel="icon" type="image/x-icon" href="/favicon.ico">
|
||
|
|
</head>
|
||
|
|
<body>
|
||
|
|
<nav>
|
||
|
|
<a href="/">[ Home ]</a>
|
||
|
|
<a href="/blog.html">[ Blog ]</a>
|
||
|
|
<a href="/projects.html">[ Projects ]</a>
|
||
|
|
<a href="/extra.html">[ Extra ]</a>
|
||
|
|
<hr/>
|
||
|
|
</nav>
|
||
|
|
|
||
|
|
<h1>NWS Incident Postmortem 11/08/2023</h1>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
On November 8th, 2023 at approximately 09:47 UTC, NWS suffered
|
||
|
|
a complete outage. This outage resulted in the downtime of all
|
||
|
|
services hosted on NWS and the downtime of the NWS Management
|
||
|
|
Engine and the NWS dashboard.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
The incident lasted 28 minutes after which it was automatically
|
||
|
|
resolved and all services were restored. This is NWS' first
|
||
|
|
outage event of 2023.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
<h2>Cause</h2>
|
||
|
|
<p>
|
||
|
|
NWS utilizes several tactics to ensure uptime. A component of
|
||
|
|
this is load balancing and failover. This service is currently
|
||
|
|
provided by Cloudflare at the DNS level. Cloudflare sends
|
||
|
|
health check requests to NWS servers at specified intervals. If
|
||
|
|
it detects that one of the servers is down, it will remove the
|
||
|
|
A record from entry.nws.nickorlow.com for that server (this domain
|
||
|
|
is where all services on NWS direct their traffic via a
|
||
|
|
CNAME).
|
||
|
|
</p>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
At around 09:47 UTC, Cloudflare detected that our servers in
|
||
|
|
Texas (Austin and Hill Country) were down. It did not detect an
|
||
|
|
error, but rather an HTTP timeout. This is an indication that the
|
||
|
|
server has lost network connectivity. When it detected that the
|
||
|
|
servers were down, it removed their A records from the
|
||
|
|
entry.nws.nickorlow.com domains. Since NWS' Pennsylvania servers
|
||
|
|
have been undergoing maintenance since August 2023, this left no
|
||
|
|
servers able to serve requests routed to entry.nws.nickorlow.com,
|
||
|
|
resulting in the outage.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
NWS utilizes UptimeRobot for monitoring the uptime statistics of
|
||
|
|
services on NWS and NWS servers. This is the source of the
|
||
|
|
statistics shown on the NWS status page.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
UptimeRobot did not detect either of the Texas NWS servers as being
|
||
|
|
offline for the duration of the outage. This is odd, as UptimeRobot
|
||
|
|
and Cloudflare did not agree on the status of NWS servers. Logs
|
||
|
|
on NWS servers showed that requests from UptimeRobot were being
|
||
|
|
served while no requests from Cloudflare were shown in the logs.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
No firewall rules existed that could have blocked this traffic
|
||
|
|
for either of the NWS servers. There was no other configuration
|
||
|
|
found that would have blocked these requests. As these servers
|
||
|
|
are on different networks inside different buildings in different
|
||
|
|
parts of Texas, their networking equipment is entirely separate.
|
||
|
|
This rules out any hardware failure of networking equipment owned
|
||
|
|
by NWS. This leads us to believe that the issue may have been
|
||
|
|
caused due to an internet traffic anomaly, although we are currently
|
||
|
|
unable to confirm that this is the cause of the issue.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
This is being actively investigated to find a more concrete root
|
||
|
|
cause. This postmortem will be updated if any new information is
|
||
|
|
found.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
A similar event occurred on November 12th, 2023 lasting for 2 seconds.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
<h2>Fix</h2>
|
||
|
|
<p>
|
||
|
|
The common factor between both of these servers is that they both use
|
||
|
|
Spectrum for their ISP and that they are located near Austin, Texas.
|
||
|
|
The Pennsylvania server maintenance will be expedited so that we have
|
||
|
|
servers online that operate with no commonalities.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
NWS will also investigate other methods of failover and load
|
||
|
|
balancing.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
<p>Last updated on November 16th, 2023</p>
|
||
|
|
|
||
|
|
<footer>
|
||
|
|
<hr />
|
||
|
|
<p style="margin-bottom: 0px;">Copyright © Nicholas Orlowsky 2023</p>
|
||
|
|
<p style="margin-top: 0px; margin-bottom: 0px;">Hosting provided by <a href="https://nws.nickorlow.com">NWS</a></p>
|
||
|
|
<p style="margin-top: 0px;">Powered by <a href="https://github.com/nickorlow/anthracite">Anthracite Web Server</a></p>
|
||
|
|
</footer>
|
||
|
|
</body>
|