consul

echo '["abcdef123458"]' /var/consul/serf/local.keyring
service consul restart

# config
cat /etc/consul/config.json

# log
/var/log/syslog

CLI
consul catalog datacenters
consul catalog nodes
consul catalog services

consul monitor
consul validate /etc/consul/config.json
consul operator raft list-peers

Redirect UI to localhost
ssh -L 8500:localhost:8500 root@node1.example.com -N

UI listen on external
https://stackoverflow.com/questions/35132687/how-to-access-externally-to-consul-ui

# cat /etc/consul/config.json
{
...
"addresses": {
"dns": "127.0.0.1",
"grpc": "127.0.0.1",
"http": "0.0.0.0",
"https": "127.0.0.1"
},
...

Remove service from specific node
ssh node1-dev consul services deregister -id=prometheus

checks
https://www.consul.io/api/agent/check.html

Get service state
https://consul.example.com/v1/agent/service/neutron

Icinga / Nagios checks
for SERVICE in $(consul catalog services); do
echo ${SERVICE}
/usr/lib/nagios/plugins/check_consul_service.py ${SERVICE}
echo
done

Ansible module
https://docs.ansible.com/ansible/latest/modules/consul_module.html

Links
https://www.consul.io/docs/agent/options.html
https://www.hashicorp.com/blog/load-balancing-strategies-for-consul
https://blog.eleven-labs.com/en/consul-service-discovery-failure-detection/