Alert publisher/ SMTP connectivity

[#1]

When you install Cloudera Manager you can configure the mail server you will use with the Alert Publisher. However, if you need to change these settings, you can do so under the Alert Publisher section of the Management Services configuration tab. Through Alert Publisher we can get the alerts for a different type of service status like Bad, Warning, Good. Under the Alert Publisher role of the Cloudera Manager Management Service, you can configure email or SNMP delivery of alert notifications and you can also configure a custom script that runs in response to an alert.

The information on how to configure the alert can be found in the official documentation of Cloudera. Please check the provided link [1].

However, we will discuss some of the common issues faced while configuring or receiving the alert delivery.

Common Issues Over Alert Publisher->

1- Sometimes we are not able to receive the alert to the SMTP/SNMP server end. While checking the alert-publisher logs, the below trace of ERROR can be seen.

ERROR org.apache.camel.processor.DefaultErrorHandler: Failed delivery for (MessageId: ID-uxxxxxxxx on ExchangeId: ID-xxxxxxx). Exhausted after delivery attempt: 1 caught: javax.mail.MessagingException: Exception reading response;
  nested exception is:
	java.net.SocketTimeoutException: Read timed out

To troubleshoot these issues, we need to first verify that the connectivity between the server and SMTP/SNMP host is good.

 -> telnet <hostname> port

 If connectivity is good, then we can either enable the debug logs and check for more loggings in alert publisher.

How to enable DEBUG->

Cloudera Manager Service -Alert Publisher - Configurations
Under the advanced java configuration for alert publisher, please append the below configuration 
"-Djavax.net.debug=all"
Then go to logs
Set the log level to debug in alert publisher

We can also verify the tcp dump and check if the message are getting accepted from CM server.

For Example->

tcpdump -i any -s 100000 -w ~/alertpub.out port <port>

2- The alert publisher fails to send out the alert due to the unavailability of the credentials information. 

ERROR org.apache.camel.processor.DefaultErrorHandler: Failed delivery for (MessageId: ID-xxxxxxxxx on ExchangeId: ID-xxxxxx). Exhausted after delivery attempt: 1 caught: javax.mail.AuthenticationFailedException: failed to connect, no password specified?

javax.mail.AuthenticationFailedException: failed to connect, no password specified?
        at javax.mail.Service.connect(Service.java:325)

Make sure credential information has been given over to the alert publisher configuration.

CM > CMS > Configuration > Alerts: Mail Server Hostname, Alerts: Mail Server Username, Alerts: Mail Server Password

[1]

https://docs.cloudera.com/documentation/enterprise/6/6.3/topics/cm_ag_email.html#xd_583c10bfdbd326ba...

https://docs.cloudera.com/documentation/enterprise/6/6.3/topics/cm_ag_snmp.html#xd_583c10bfdbd326ba-...

https://docs.cloudera.com/documentation/enterprise/6/6.3/topics/cm_ag_alert_script.html#concept_sfx_...