We have a kafka cluster running in kubernetes using Confluent Operator, works like a charm, but trying to get email notifications failes with the following log entry:
WARN [control-center-heartbeat-1] sending=failure email to=eddie.olsson@ri.se with subject=Raw Archive lag from trigger=53d7d8e8-4e0e-42f9-abc4-03e32b8de90a {} (io.confluent.controlcenter.alert.EmailSender)
org.apache.commons.mail.EmailException: Sending the email to the following server failed : smtp.office365.com:587
at org.apache.commons.mail.Email.sendMimeMessage(Email.java:1469)
at org.apache.commons.mail.Email.send(Email.java:1496)
at io.confluent.controlcenter.alert.EmailSender.send(EmailSender.java:43)
Caused by: javax.mail.MessagingException: Exception reading response;
at com.sun.mail.smtp.SMTPTransport.readServerResponse(SMTPTransport.java:2369)
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:2096)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:712)
at javax.mail.Service.connect(Service.java:388)
at javax.mail.Service.connect(Service.java:246)
at javax.mail.Service.connect(Service.java:195)
at javax.mail.Transport.send0(Transport.java:254)
at javax.mail.Transport.send(Transport.java:124)
at org.apache.commons.mail.Email.sendMimeMessage(Email.java:1459)
at com.sun.mail.util.TraceInputStream.read(TraceInputStream.java:124)
at com.sun.mail.util.LineInputStream.readLine(LineInputStream.java:92)
at com.sun.mail.smtp.SMTPTransport.readServerResponse(SMTPTransport.java:2349)
I found netcat on the controlcenter pod and tried connecting to the above smtp server on port 587 but it never returns any response at all. Trying the same thing from another pod in the same k8s cluster gives the expected SMTP respons from the server.
Are there any settings for the control center or it’s deployment that limits outgoing network connections? If not, where do I look for a solution to this?