Activate auto-failover on CA SDM 14.1 in AA

[Legacy User]

Hello!

 

I want to activate auto-failover on SDM 14.1 in Advanced Availability. I was following this link: https://wiki.ca.com/display/CASM1401/How+to+Enable+Auto-Failover, but I wanted to ask some questions:

1. The Tomcat Server can be the same of SDM?
2. If yes, what is the location of TOMCAT_HOME?
3. And how I can restart the Tomcat?

Thank you.

[Raghu Rudraraju]

Hi Diogo,

 

HealthServlet Tomcat CANNOT be on the same as SDM Tomcat.

 

This was also discussed in the Advanced Availability webinar last year. Webinar Video+PDF of slides + Q&A  -  https://communities.ca.com/message/119411839#119411839

 

Maybe the webinar would help in clarifying it a bit more?

 

_R

[Legacy User]

Hello Raghu!

I'll take a look on this webinar. Certainly will clarify, but I wonder why this information isn't already on the wiki.

Thank you for answering!

Regards,

Diogo Nobrega

[Raghu Rudraraju]

Hi Diogo,

 

 

Though this article was written for 12.9, the same steps to install the new Tomcat for Health Servlet would still apply. Maybe this will help you a bit more?

http://www.ca.com/us/support/ca-support-online/product-content/knowledgebase-articles/tec613953.aspx

 

I realize that the 14.1 wiki is missing key wording about keeping Health Servlet Tomcat in a separate instance of Tomcat than SDM Tomcat.  Thank you for bringing this to our attention. We’ll try to get that cleared up shortly.

 

 

_R

[Legacy User]

Hi Raghu,

 

I followed the instructions on this link and I was able to install both Tomcat and health servlet! Thank you!

 

I don't know if here is the right place to ask this, but when I try to access failover link (http://server:port_number/HealthServlet/FailoverServlet), the server returns a timeout message: "Exception during failover. Reason : Timeout waiting for reply after 60 seconds". The GetHealth link works without error.

 

Regards,

 

Diogo Nobrega

[paulofreire]

I runned the http://localhost:8100/HealthServlet/FailoverServlet on the standby server, it was promoted to the new background server but in this process, the Service Desk Service of the original background goes down. Is it the spected behavior?

[Raghu Rudraraju]

That is expected behavior that  SB --> becomes current BG    and  BG SDM services are shutdown.

 

Also, for your question about: "I try to access failover link (http://server:port_number/HealthServlet/FailoverServlet), the server returns a timeout message: "Exception during failover. Reason : Timeout waiting for reply after 60 seconds". The GetHealth link works without error.

 

The above is expected out of the Failover servlet too.

[paulofreire]

One more doubt Raghu

Is there an procedure for failover if we have more than one application server in the environment.

Supose we have 2 application servers with many webengines in each.

If one of the application servers goes down, how do I do the failover procedure in this case?

Too in this scenario, there is a procedure to configure load balancing between these 2 application servers?

[Raghu Rudraraju]

When Application servers are involved, you basically check the HealthServlet to ensure that the server is healthy.  Based on the return code of that servlet, a Load balancer could stop sending new user login requests to that bad server, by removing it from load balancer pool.

 

An external load balancer is required for something like this. 14.1 WIKI documents an example scenario for F5 load balancer.  Similar approaches could be followed for other load balancers too I suppose.

 

_R

[naira11]

Hi Raghu,

 

+ Sanjay_Kumar

 

I am from the CA Service Management documentation team and I have tried to capture the missing information in wiki here:

https://wiki.ca.com/display/CASM/.Deploy+the+Health+Servlet+on+the+Application+Server+v14.1

 

Please verify and let me know your feedback.

 

Regard,

Rajashree Nair

[Raghu Rudraraju]

Thank you Rajashree.  Appreciate the quick turn around on this matter.

 

Diogo, the wiki page has now the note about deploying HealthServlet onto a separate Tomcat.

https://wiki.ca.com/display/CASM1401/Deploy+the+Health+Servlet+on+the+Application+Server

_R

[wteixeira]

Thanks for sharing this Raghu.