design docs in https://help.torproject.org/tsa/howto/cache/ launch checklist: 1. alternatives listing and comparison (done) 2. deploy a test virtual machine by hand, say `cache-01.tpo` (done) 3. benchmark the different alternatives (done, ATS and nginx comparable) 4. setup secondary node with Puppet, say `cache-02.tpo` (done) 4. validation benchmark against both nodes (done) 5. lower DNS to 10 minutes wait an hour (done) 6. open firewall (done) 7. lower DNS to 3 minutes (done, around 2019-11-05 16:00:00) 8. point DNS to caches (done) 11. raise DNS back to 1h if all goes well. (done!) Post launch tasks: 1. update documentation to fill in information from template (done) 2. hit ratio stats in to Prometheus, separate ticket? (done, although missing syslog buffer, see legacy/trac#32461) 3. convert existing varnish setups into Nginx (probably requires Puppet refactoring, see legacy/trac#32462) Disaster recovery: 1. flip DNS back to backend