https://blog.cloudflare.com/today-we-mitigated-1-1-1-1/

On May 31, 2018 we had a 17 minute outage on our 1.1.1.1 resolver service; this was our doing and not the result of an attack.

Cloudflare is protected from attacks by the Gatebot DDoS mitigation pipeline. Gatebot performs hundreds of mitigations a day, shielding our infrastructure and our customers from L3/L4 and L7 attacks. Here is a chart of a count of daily Gatebot actions this year