I don't know of any uptime SaaS providers that support monitoring websites on their onion service endpoints.
cron
Until that day comes (as it's hard to think of a reason why any admins shouldn't make their websites accessible at a .onion address--which benefits the privacy of their visitors), a simple solution is just to spin up a small micro sever (such as the "always free" server in google's cloud) that does a simple curl over tor every 1 minute and sends an email alert if curl exits non-zero.
For example, if you want to monitor torproject.org's onion service (qrmfuxwgyzk5jdjz.onion):
user@disp9739:~$ curl -IL --socks5-hostname 127.0.0.1:9050 http://qrmfuxwgyzk5jdjz.onion/
HTTP/1.1 200 OK
Date: Fri, 13 Nov 2020 15:16:44 GMT
Server: Apache
Content-Location: index.html.en
Vary: negotiate,accept-language,Accept-Encoding
TCN: choice
X-Content-Type-Options: nosniff
X-Frame-Options: sameorigin
X-Xss-Protection: 1
Referrer-Policy: no-referrer
Content-Security-Policy: default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline';
Last-Modified: Fri, 13 Nov 2020 15:12:24 GMT
ETag: "3cec-5b3fe74ab4600"
Accept-Ranges: bytes
Content-Length: 15596
Cache-Control: max-age=3600
Expires: Fri, 13 Nov 2020 16:16:44 GMT
Content-Type: text/html
Content-Language: en
user@disp9739:~$
If you're running debian, then you can execute the following commands to create a simple cron job that will monitor your website:
sudo apt-get install tor curl mailutils
cat > /etc/cron.d/tor-hidden-service-monitoring <<'EOF'
* * * * * root url='http://qrmfuxwgyzk5jdjz.onion/'; curl -IL --socks5-hostname 127.0.0.1:9050 "${url}" || echo "Unable to access ${url}" | mail -s "ALERT: hidden service inaccessible" [email protected]
EOF
The above commands will install tor, curl, and the mail command and create a simple cron job that will attempt to access http://qrmfuxwgyzk5jdjz.onion/ every 1 minute and email [email protected] if it fails.
mon
To reduce false-positive email alerts, you could use mon to only trigger an alert after multiple consecutive queries fail.
sudo apt-get install tor torsocks mon
cat > /usr/lib/mon/mon.d/torsocks_http.monitor <<'EOF'
#!/bin/bash
################################################################################
# File: torsocks_http.monitor
# Version: 0.1
# Purpose: Wraps the http.monitor script with torsocks to monitor .onion sites
# https://tech.michaelaltfield.net/monitoring-tor-onion-websites-uptime-alerts
# Authors: Michael Altfield <[email protected]>
# Created: 2021-03-12
# Updated: 2021-03-12
################################################################################
export DIR_PATH=`dirname ${0}`
exec /usr/bin/torsocks --isolate ${DIR_PATH}/http.monitor -t 60 "$@"
EOF
hostgroup torproject_onion qrmfuxwgyzk5jdjz.onion
watch torproject_onion
service http
interval 5m
monitor torsocks_http.monitor
period
alertafter 10
alertevery 1h strict
alert mail.alert [email protected]
upalert mail.alert [email protected]
systemctl restart mon.service
Tor2Web
Finally, you can also use Tor2Web to create a clearnet proxy to your .onion site, then point your existing uptime monitoring IaaS tool at it.
Source
The above solutions were originally published in the following article titled Monitoring Tor .onion Websites (uptime alerts)
