As we all know that attending interview is one of the toughest job.Because, you never know the interviewer expectation and his mindset.He/She may be started asking questions which are related their current working environment and interviewee may not know the those setups. Companies also adding more competencies to filter the candidates. One of the important skill sets to filter the resources is “Cluster” . If you go for any L2/L3 interviews, definitely you can expect the questions from cluster irrespective of their project demands. LOL!!!
This article is going to help you to manager cluster related questions in Veritas cluster and redhat cluster.I am not going to teach each and every command on the cluster technologies but help you explain the setup if you don;t have one in current work environment.
Solaris:
Q: Are you working cluster environment ?
A:Yes.I am working Veritas cluster .Its a zone failover model cluster.
(:- Here interviewers will try to screw you by asking the cluster setup.The next question will be …
Q:Zone failover model cluster ? How it works ?
A: Veritas cluster software has been installed on two global zones and configured .
We have configured the failover service group and added the zone as resource.zones are installed on shared storage and LUNS are visible on both the cluster nodes.If there is any issue on one global zone ,the service group will automatically fail-overs to second global zone.In other words, zone will be halted on one node and booted in other node.
This kind of cluster setup is very less compare to the traditional & complex start/stop scripts for application.
Off-course without having the hands on experience ,it is hard to explain with confidence.So Practice the VCS cluster yourself before attending any interviews.
There are three article in Unixarena to get the setup to be done on VMWARE workstation to practice yourself.
1.How to install and configure two node VCS cluster.
2.Create a new service on veritas cluster.
3.Add the zone as resource in service group.
Redhat Linux:
The same trick you can follow on the Linux interview as well. Redhat Cluster as well supports the virtual machine failover. If the interviewer ask about the redhat cluster, you simply say that ” I am working two node redhat cluster – virtual machine failover setup”.
Here is the overview of the virtual machine failover setup using redhat cluster.
Redhat cluster has been installed on both the cluster nodes and configured as two node cluster.We have KVM packages installed and configured with the virtual guests on both the nodes.Those virtual guests aka virtual servers have added in to the redhat cluster as resource and if there is any issues with one server, all the virtual machine will be halted/killed and those will be booted on the second cluster node.
The beauty of redhat cluster + KVM is that virtual machines can be failover to other node without hating/rebooting it .
The below articles will be help you to setup the environment redhat cluster environment.
1.Configure the redhat cluster with virtual machine.
2.Test the live migration for the virtual guests.
Hope now you can able to manage the cluster related questions in interview.
I am sure that if you explain these setup with confidence, definitely interviewer will not ask further question on this.