Naggappan Ramukannan's questions

I have may aws ec2 instances running in dev account and most of the instances i see cpu utlization doesn't go most of the time more than 5% . For example even in one of the kubernetes cluster where kafka is running it is not exceeding 5 or max 6% of cpu utlization when we used t3.xlarge (16gb ram and 4vcpu) machine for kafka cluster setup.

So my question is there an way to find out if i am really fully utlizing the instances for which we have opted for so that i can downgrade my instances type to low cost one if it is not fully utlized. I saw aws compute optimizer but that is saying most of the instances are optimized only 1 or 2 it shows as not optimized with under utlized.

Also most of the application like may be kafka are by default requesting 8gb ram and good cpu for better usage but the cloud watch chart doesn't actually show as if its fully utlized.

Hence is there any way to tacle this and reduce the ec2 costing in aws?

I have enabled the cloud trail logs and I get the logs to my graylog system. Now how can I do analysis on the following use cases:

• What if same user is trying to login and using from different Source IP's
• Need to analyse like if particular user is logging in with some region (say US) then suddenly he tries to login from Europe.
• Basically trying to develop some security related use cases.

I am ok to do develop my own application if graylog doesn't support the above. What is the best way to do it? Send all logs to Kafka and then from there use an application to track it?

Hi I have created a bucket and enabled cloud trail also including s3 object level api logging. Now when I create some s3 ACL via UI the I get the logs in cloud trail but when I Create the same ACL via json Bucket->permissions -> bucket policy (And enter my JSON value and save) then this is not getting tracked

Hi I used openstack qcow2 format and run the graylog server

Now I can access my openstack machine only using floating public IP address and not via private Internal IP address.

Here when I do graylog using public Ip address I get the following error,

"http://172.29.18.94:9000/api/"

Which is actually my private IP address.

How can i change IP and port should be in 8080, I followed document "http://docs.graylog.org/en/2.4/pages/installation/openstack.html" to install

If a application is developed as a REST API based with separate UI and backend tiers, and we have tools to deploy the servers in a few minutes, why do we need live migration support?

Say to move from one region to other, we can simply create a new load balancer in the new region and then create new VMs over there and just switch the DNS address to new IP. It's done right? So why do many companies look for live migrations?

My current configuration setup is as below,

AWS ELB(https / 443 to 80) --> Webserver_UI ( nginx 80 ) -> nodejs 

AWS ELB2(https / 8080 to 8080) --> Webserver (nginx 8080) -> localhost tomcat 8081 -> Java code

Now my question is Do I really need Nginx for my 2nd webserver? As tomcat can be directly taking the request from AWS ELB and certificates are taken care by ELB itself.

But every one keep Nginx, so what is the real advantage of this setup?

I know I can try "AWS Elastic Beanstalk" instead of nginx but on cost wise I don't want to try it.

Hi I am trying to send mail using mutt command as below,

mutt -s "test" [email protected] </dev/null

This fails with following error,

sendmail: Cannot open mail:25
Error sending message, child exited 1 ().
Could not send the message.

This issue happens in fedora 22 and fedora 23 machines. I used to run the same in fedora 12 and it works fine

Tried to modify following value in file "/etc/ssmtp/ssmtp.conf"

mailhub=mail

to

mailhub=fqdn_of_my_machine

Still I get similar error as below,

sendmail: Cannot open fqdn_of_my_machine:25
Error sending message, child exited 1 ().
Could not send the message.

Even sendmail I get same error as above,

sendmail [email protected]  < /tmp/file1
sendmail: Cannot open fqdn_of_my_machine:25