• Managed services such as Amazon RDS cannot be monitored with the Connectivity monitoring rule.
• As an alternative method, we recommend that you check whether the host on which the agent is installed can connect to the managed service using a plugin like the following.
  • check-tcp
    • Confirm whether or not you can connect to the TCP port of the target managed service
    • See Running checks on TCP servers - Mackerel Help for more information
• There are also check plugins that specialize in various middleware and protocols. Consider the following according to your target managed service (consult the README of each plugin for details)
  • check-mysql
  • check-postgresql
  • check-redis
  • check-http
  • check-smtp

For reference

• What kind of configuration is Mackerel's connectivity monitoring working with?