ETCDCache Storage: Connection failed

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?