使用cdh安装hadoop时候，报“ MainThread agent ERROR Failed to connect to previous supervisor.”
Installation failed. Failed to receive heartbeat from agent.
- Ensure that the host's hostname is configured properly.
- Ensure that port 7182 is accessible on the Cloudera Manager Server (check firewall rules).
- Ensure that ports 9000 and 9001 are not in use on the host being added.
- Check agent logs in /var/log/cloudera-scm-agent/ on the host being added. (Some of the logs can be found in the installation details).
- If Use TLS Encryption for Agents is enabled in Cloudera Manager (Administration -> Settings -> Security), ensure that has on the host being added. Restart the corresponding agent and click the Retry link here.