The celery worker of refill-api was failing partly because it is a consumer of tools-redis.
On investigation, it appears to be caused by some kind of DNS issue.
bstorm@tools-sgebastion-08:~$ nslookup 172.16.1.166 Server: 208.80.154.143 Address: 208.80.154.143#53 Non-authoritative answer: 166.1.16.172.in-addr.arpa name = tools-redis-1003.tools.eqiad1.wikimedia.cloud. 166.1.16.172.in-addr.arpa name = canary1027-01.cloudvirt-canary.eqiad1.wikimedia.cloud
I believe tools-redis-1003 should just be 172.16.1.107
bstorm@canary1027-01:~$ nslookup tools-redis-1003.tools.eqiad1.wikimedia.cloud
Server: 208.80.154.143
Address: 208.80.154.143#53
Non-authoritative answer:
Name: tools-redis-1003.tools.eqiad1.wikimedia.cloud
Address: 172.16.1.166
Name: tools-redis-1003.tools.eqiad1.wikimedia.cloud
Address: 172.16.1.107