Petter Lund, one of our Cloud Infrastructure Specialists spoke about Cloud and Iaas in general and gave a tour of the basic features in City Cloud.
For those of you that couldn’t make the live class, here is the replay.
Questions answered during the class
Q: Can You load balance a load-balancer? What happens if London-site go down?
A Yes, you can do that, using for instance DNS with very short TTL, or create an automated test that checks connectivity towards your load balancer, in case that the load balancer stops responding the DNS zone is updated without that particular Load balancer IP.
In our demo, if the load balancer in London would stop responding the site would go down.
So to avoid that you could set up a second load balancer and use DNS to load balance between them for instance.
Q: If the Load Balancer is a SPOF, what is the point? Isn’t it just moving the problem?
A: Well its not really moving the problem one step out, since a load balancer help distribute connections/request over a number of servers one limits the risk of having a scenario where
There are to many requests coming in to the single server and the server wont be able to handle them, If setup of the application is done the “right” way adding new servers behind the load balancer shouldn’t be a problem and could be useful for spikes in traffic.
But this we will talk more about in future sessions,
Q: Where do you configure warnings (e.g. e-mail) to let you know one of the servers went down?
A: You could use any monitoring tool available to set up monitoring of the servers to send out alerts in case of issues, one that we provide is the City Monitor tool that you could use.
It can do ping tests or check urls if you wish
Q: What types of balance algorithm can setup in the load balancer v2? Can manage all zones?
A: You can set up the same type of balance algorithms, but you can have more then one listener, i.e. you can have 2 listeners for the same load balancer.
You can have a load balancer in one zone and servers in all zones, how the load balancer is connecting to the load balancer depends on if you added the member servers with thir public IP or internal IP, if you wish to use internal IP you need to set up a VPN connection between all the networks and the network the load balancer is active in.