* Sentry: https://sentry.io/welcome/
* Logentries: https://logentries.com/
* Loggly: https://www.loggly.com/
* Opbeat: https://opbeat.com/
* Papertrail: https://papertrailapp.com/
Sentry is open source and there is even an official up-to-date docker image: https://hub.docker.com/_/sentry/
Loggly published an "Ultimate Guide to Logging": https://www.loggly.com/ultimate-guide/