I have certain doubts about load balancing VMs in Azure.
When i add a vm to an existing deployment(already running VM) it assigns the same dns name to the added VM but there is no Virtual IP assigned to the VM. But the port shows load balanced VM.
I believe what you're saying is that VM number 2 through N appear to come online with the same DNS name as VM number 1.
This is expected behavior. The VIP is the Virtual IP address, which is the DNS name on the outside edge of the load balancer. This should be the same for every load balanced machine behind the load balancer. The internal IP of each instance is known as the DIP, or Dedicated IP address.
The job of the load balancer is to take requests against the VIP and redistribute those calls to each of the DIPs. Once the request is serviced by an individual instance, it is routed back to the caller via the load balancer.
Is that what you're seeing, or am I misunderstanding your question?
Related
I just started learning load balancers. Taking a server side application (http/https) load balancer as an example, I assume it listens a specific ip address, then forward the http requests to available servers based on its algorithm.
So is it possible for a load balancer to become a bottleneck? Because it's listening a specific ip address, all requests will first go to the single load balancer. So I think there could be a scenario where the amount of traffic is beyond the limit/capacity of the load balancer.
When it becomes a bottleneck, what can we do? Can we use multiple load balancers?
I think one possible solution is to use multiple load balancers and expose all the ips to clients. (This sounds like client side load balancing) So when a client wants to send a request, it can pick from the ip pool and then send a request to one of the load balancers. (For example, ZooKeeper could be used here.) Is this a working solution? Is there any other way to use multiple load balancers?
Thanks.
Ethan
Your last suggestion works with adding a little twist: The usual approach is to publish the load balancer IP addresses under the same domain name.
This is called DNS load balancing. Clients will ask for the IP resolution for your load balancer's domain name and they will get different IP addresses on a round-robin fashion.
To configure DNS load balancing you have to add multiple A records for your load balancer's domain name to your DNS configuration. Here you can find an example guide for that.
I have an Azure standard internal load balancer inside a VNET that contains several virtual machines. Two of the VMs are not listed as options when I want to add them to a back end pool of the load balancer. They are were created under ARM and not included in any other load balancer pool. They are also in the same VNET that is associated to the backend pool.
If I create a basic load balancer, I can see them and successfully add them to the pool. Is there documentation on the VM requirements that must be met before you can add a VM to a pool within a standard load balancer?
When you add the backend pool, you will see Only VMs in the same region with standard SKU public IP or no public IP can be attached to this load balancer.
In this case, you can randomly disable the public IP address from the virtual machine---network interface---Ip configurations---ipconfig1---disabled---save. Then you can add the desired VMs to backend pool again.
Following along from the Use a static IP address with the Azure Container Service (AKS) load balancer documentation I have created a static IP and assigned it to the load balancer. This worked fine on the initial run, but now I am getting the following error and the external ip for my load balancer is stuck <pending> (personal info omitted):
Failed to ensure load balancer for service default/[...]: network.LoadBalancersClient#CreateOrUpdate: Failure responding to request: StatusCode=400 -- Original Error: autorest/azure: Service returned an error. Status=400 Code="PublicIPReferencedByMultipleIPConfigs" Message="Public ip address /subscriptions/[...]/providers/Microsoft.Network/publicIPAddresses/[PublicIPName] is referenced by multiple ipconfigs in resource
As far as I can tell, this isn't referenced by multiple configs - just the load balancer service that I'm trying to run. Removing the loadBalancerIP option from my yaml file allows this to work but then I don't think the server address is static - which is not ideal for the applications trying to communicate with this container
Is this supposed to be happening? Is there a way to configure this so that the same IP can be reused after the container restarts?
Seeing as this issue appears to still be present, for anyone else stumbling upon this issue it seems that the Azure load balancer resource itself may be taking the first configured static IP address.
GitHub issue response:
the first public IP address created is used for egress traffic
Microsoft Docs:
Once a Kubernetes service of type LoadBalancer is created, agent nodes are added to an Azure Load Balancer pool. For outbound flow, Azure translates it to the first public IP address configured on the load balancer.
As far as I can tell, once you provision an IP address and configure an AKS load balancer to use it, that IP gets picked up by the provisioned load balancer resource in Azure. My best guess is that when Kubernetes attempts to provision a new load balancer with the same IP address, if the previous Azure load balancer still exists the IP config will fail as it's still in use.
Workaround was to provision an extra static IP (one specifically for the Azure load balancer resource, and one for the actual AKS load balancer service) to avoid conflicts. It's obviously not ideal but it solves the issue...
I am new to Google compute engine and I am try to setup network load balancing having 2 VMs for serving web pages.
For ex, I have 2 VMs - app1 and app2 - both having apache server and serves simple web page.
Both VMs are running with Red Hat Enterprise Linux Server release 7.0 (Maipo)
I am able to access both web pages through the IP in browser.
I created network load balancing setup and both apps are showing in green in target pool which means load balancer is able to connect to both VMs.
But, when I hit the IP of load balancer, it is rendering page from only one server. If I manually stop the server in the VM, load balancer IP redirects to other app. I believe load balancer is able to identify health of both VMs and able to redirect.
But it is not balancing the traffic. Can anyone help me to solve this issue?
I think that the network load balancer doesn't forward the traffic on a round-robin basis. I was able to test it with the load balancer setup that I have. As per the documentation:
By default, to distribute traffic to instances, Google Compute Engine picks an instance based on a hash of the source IP and port and the destination IP and port.
HTTP/S load balancing will proxy requests in a round-robin fashion. https://cloud.google.com/compute/docs/load-balancing/http/
Currently I have two websites running on single Amazon EC2 and using Apache web server. Configuring Apache to use virtual host and use a single IP address was simple . But I think Amazon gives you up to 5 IP addresses and would like attach two IP addresses to a single EC2 instance and use those IP addresses for each site.
How do I configure the server that Website A uses one of the IP address for incoming and outgoing data?
Unfortunately, you can only map 1 elastic IP per instance. Its a nasty limitation, because I would love to setup multiple sites using SSL with default port of 443 but I cannot. I usually just use other ports if I have to, but that is not best practice.
The associated elastic IP to the one instance is free. You can set that up in the management console or through the API. Your server should come with its own internal IP address, and the elastic IP gets translated to that.
There are things that you can do with AWS load balancing, which allow you to use multiple ssl sites to one instance.
You can now do this if you run your instance in a VPC.
You can create multiple ENIs (Elastic Network Interfaces) and associate any number of them with a single instance.
The announcement for this feature is at http://aws.typepad.com/aws/2012/07/multiple-ip-addresses-for-ec2-instances-in-a-virtual-private-cloud.html