ALM-12043 DNS Parsing Duration Exceeds the Threshold (For MRS 2.x or Earlier)

Description

The system checks the DNS parsing duration every 30 seconds. This alarm is generated when the DNS parsing duration exceeds the threshold (the default threshold is 20,000 ms) for multiple times (the default value is 2).

You can change the threshold by choosing System > Threshold Configuration > Device > Host > Network Status > DNS Resolution Duration > DNS Resolution Duration.

This alarm is cleared when hit number is 1 and the DNS resolution duration is less than or equal to the threshold. This alarm is cleared when hit number is not 1 and the DNS resolution duration is less than or equal to 90% of the threshold.

Attribute

Parameters

Impact on the System

• Kerberos-based secondary authentication is slow.
• The ZooKeeper service is abnormal.
• The node is faulty.

Possible Causes

• The node is configured with the DNS client.
• The node is equipped with the DNS server and the DNS server is started.

Procedure

Check whether the node is configured with the DNS client.

1. Go to the MRS cluster details page and choose Alarms.
2. View the alarm details to obtain the value of the HostName field in Location.
3. Use PuTTY to log in to the node for which the alarm is generated as user root.
4. Run the cat /etc/resolv.conf command to check whether the DNS client is installed.

   If information similar to the following is displayed, the DNS client is installed and started:

   namesever 10.2.3.4  
   namesever 10.2.3.4

   • If yes, go to 5.
   • If no, go to 7.

5. Run the vi /etc/resolv.conf command to comment out the following content using the number signs (#) and save the file:

   # namesever 10.2.3.4  
   # namesever 10.2.3.4

6. Check whether this alarm is cleared after 5 minutes.
   • If yes, no further action is required.
   • If no, go to 7.

Check whether the node is equipped with the DNS server and the DNS server is started.

7. Run the service named status command to check whether the DNS service is installed on the node.

   If information similar to the following is displayed, the DNS server is installed and started:

   Checking for nameserver BIND  
   version: 9.6-ESV-R7-P4 
   CPUs found: 8 
   worker threads: 8 
   number of zones: 17 
   debug level: 0 
   xfers running: 0 
   xfers deferred: 0 
   soa queries in progress: 0 
   query logging is ON 
   recursive clients: 4/0/1000 
   tcp clients: 0/100 
   server is up and running

   • If yes, go to 8.
   • If no, go to 10.

8. Run the service named stop command to stop the DNS server.
9. Check whether this alarm is cleared after 5 minutes.
   • If yes, no further action is required.
   • If no, go to 10.

10. Collect fault information.
    1. On MRS Manager, choose System > Export Log.
    2. Contact the O&M engineers and send the collected logs.

Reference

None