ETCDCache Storage: Connection failed

[khartahk]

I'm trying to integrate github-authorized-keys with bastion. It's working without the etcd caching. When I enable caching I get the following error (it still works just the key is always requested from github):

{"class":"ETCDCache","level":"error","method":"Set","msg":"Storage: Connection failed","time":"2020-04-03T20:04:22Z"}

etcd is installed on the host Ubuntu 18.04 and is visible in github-authorized-keys docker when running
docker exec -it github-authorized-keys netstat -tlpn
output:

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 127.0.0.1:2379          0.0.0.0:*               LISTEN      -
tcp        0      0 127.0.0.1:2380          0.0.0.0:*               LISTEN      -

Running etcdctl --endpoints=http://localhost:2379 set foo bar works and returns bar

What am I missing?