I have been working on the Azure monitoring side for a while. I need your inputs for one of my requirement.
We have lot of IaaS VM’s both SQL and Non-SQL provisioned in our subscriptions. We are paying non-trivial amount for these VM’s. I am trying to come up w/ solution to identify low usage machines and during what times( night, early morning etc) the usage is very low. With this, I can take an action by either shut down VM’s during low usage period or reduce VM size.
For this, I am trying couple of options like Azure Advisor, Azure metrics for CPU usage, Network I/O, Disk Read/Write parameters. But considering only these might not help. Because, your network I/O might be having load balancer requests which cannot be considered.
So I need to come up w/ actual IIS requests went in during the given period.
Can you recommend on how to identify low usage VM’s? It would be a great help.
Can you recommend on how to identify low usage VM’s?
Generally, we will based on CPU usage to identify low usage VM.
Network traffic in or out of one application might be having load balancer requests, but network traffic in or out of this VM will not have load balancer, we also can use this to identify low usage VM.
So I need to come up w/ actual IIS requests went in during the given
period.
We can use OMS to monitor IIS request of each VMs in Azure, please follow this article to configure OMS.
like this:
Also we can config zabbix on one Azure VM and use that to monitor all VMs.
Related
I have a Web server (Web01) setup in VM. Currently, I facing performance issue on the Web Server, The bottleneck is too many request, the web server is not enough process power to execute. So I have 2 options to resolve this problem.
Increase CPU and Memory
Setup Web02 in VM (Same VM Host of Web01) and build NLB.
I don't know above 2 options which is the best. Actually, I struggle option 2 that if I setup 2 web server's in same VM host, is the performance is bester than option 1?
I can share some thoughts with you on the pros and cons of NLB, but I can't directly help you make a choice.
Network load balancing has several potential advantages. By distributing network traffic among multiple servers or virtual machines, processing is faster than if all traffic flows through a single server. If demand decreases, servers can be taken offline, and the feature will balance traffic among the remaining hosts. NLB provides fault tolerance at the network layer, ensuring that connections are not directed to servers that are down. Network Load Balancing also enables organizations to rapidly scale server applications by adding hosts and then distributing the application's traffic among the new hosts.
But it still has some drawbacks. It cannot detect service interruption, only by IP address. If a particular server service fails, WNLB cannot detect the failure and will still route requests to that server. The current CPU load and RAM utilization of each server cannot be considered when distributing the client load.
I am having difficulty understanding Azure Availability sets, specifically, what exactly i need to to do ensure my app running on my vm is utilizing Availability sets to be more available.
Lets say i am creating an application that runs on a single VM and i want to make it more resistant to hardware failure.
Option 1:
I create an Availability Set with 2 fault domains and then create a VM on this Availability set.
Is that it?
If there is a hardware failure on the rack hosting my VM, does azure now take care of ensuring the VM stays up and running?
Option 2:
i have to have two servers Vm1 & Vm2, both in the availability set but one on fault domain 1, one on fault domain 2.
i have to then set up a cluster of sorts for my application. In this case the availability set is simply allowing me to be sure that the two servers in my cluster are not on the same hardware, but the plumbing to ensure the application can take advantage of two servers and is highly available is still down to me.
Is option 1 or option 2 the correct way in which Availability Sets work in relation to fault domains?
Appreciate any clarity that can be provided.
Azure deals with hardware failure in two ways, Availability Sets and Availability Zones. AS is all about making sure that your app does not go down even if hardware failure happens within a Data center aka Zone itself. AZs are all about making sure your app does not go down even if the whole data center aka Zone is down. More details here.
Now to understand best practices around availability take a look at the best practices, specifically for VMs can be found here.
A Single VM instance is defined as follows, reference:
"Single Instance" is defined as any single Microsoft Azure Virtual Machine that either is not deployed in an Availability Set or has only one instance deployed in an Availability Set.
So one VM in or not in an availability set does not make any difference, for this you need at least two VMs and which are in an AS using FDs and UDs so Azure will take care of this by making sure that both VMs are running on separate Hardware to avoid your app going down.
One VM in an Availability set is nearly as good as a VM with no Availability set.
If you are placing two or more VMs in an AS and those are identical then you can add a load balancer to distribute traffic.
You can also use AS without a Load balancer if you are not interested in traffic distribution. One scenario can be where you want to switch to a secondary VM only when primary is unavailable.
Also, do understand it is not required to have identical VMs in an AS.
Virtual machine scale set is a good option if you are looking for a high availability solution with VMs.
I have a VM that runs IIS and SQL server for an enterprise application used by around 100 users.
Right now I just have this VM but I would like to add some availability. It’s not critical to have zero downtime application but at least that if by some reason the server fails then I’m able to wake up a secondary instance and reroute traffic to it.
So I guess this is done by using Availabilty Sets but what I understand is that I have at least to have two VMs in the availability set and load balancer so traffic is redirected round robin to each VM. By using the above approach that means that I must have to pay for having two instances with same specs I guess.
What I would like and don’t know if this is possible is like having same above scenario where one the of the VMs is stopped so I don’t get any charge and in case of VM failure I can started maybe manually so the application works again. If this is possible how does the hard drive is available so that the other VM always have the latest data.
If it’s not possible then can I have then for the availabilty set a second VM with the lowest specs that my app can support so if the main VM fails at least critical users can still access the app (maybe performance won’t be great but app will work) and when main VM is functional again then main traffic is again redirected to main VM.
you can achieve this by having 2 vms with premium disks only and having one as a cold backup. single vm qualify for an SLA if they only use premium disks, SLA would be 99.9% afair.
with AV sets - you need to have at least 2 running vms.
Is there any limit to send/receive an API response service from windows Azure Virtual Machine?
As far as I know, there isn't any limit to send/receive an API response from Azure VM. The VM create in Azure, it works as a server same as a on-premises server.
About the Azure VMs limits, refer to the link.
The Azure VM's performance according to different VM size.
No, I think there isn't any limit as such. VMs are billed on capacity and no of hours run.
No limit, but you do need to pay for bandwidth after a certain point. Check here: https://azure.microsoft.com/en-us/pricing/details/bandwidth/.
The first 5 Gigabytes per month of outbound traffic are free.
After that you have to start paying something. Your VM will usually cost way more than the bandwidth (license, VM size, storage).
I am starting to develop a webservice that will be hosted in the cloud but needs higher availability than typical cloud SLAs provide.
Typical SLAs, e.g. Windows Azure, promise an availability of 99.9%, i.e. up to 43min downtime per month. I am looking for an order of magnitude better availability (<5min down time per month). While I can configure several load balanced database back-ends to resolve that part of the issue I see a bottleneck at the webserver. If the webserver fails, the whole service is unavailable to the customer. What are the options of reducing that risk without introducing another possible single point of failure? I see the following solutions and drawbacks to each:
SRV-record:
I duplicate the whole infrastructure (and take care that the databases are in sync) and add additional SRV records for the domain so that the user tying to access www.example.com will automatically get forwarded to example.cloud1.com or if that one is offline to example.cloud2.com. Googling around it seems that SRV records are not supported by any major browser, is that true?
second A-record:
Add an additional A-record as alternatives. Drawbacks:
a) at my hosting provider I do not see any possibility to add a second A-record but just one... is that normal?
b)if one server of two servers are down I am not sure if the user gets automatically re-directed to the other one or 50% of all users get a 404 or some other error
Any clues for a best-practice would be appreciated
Cheers,
Sebastian
The availability of the instance i.e. SLA when specified by the Cloud Provider means the "Instance's Health is server running in the context of Hypervisor or Fabric Controller". With that said, you need to take an effort and ensure the instance is not failing because of your app / OS / or pretty much anything running inside the instance. There are few things which devops tend to miss and that kind of hit back hard like for instance - forgetting to configure the OS Updates and Patches.
The fundamental axiom with the availability is the redundancy. More redundant your application / infrastructure is more availabile is your app.
I recommend your to look into the Azure Traffic Manager and then re-work on your architecture. You need not worry about the SRV record or A-Record. Just a CNAME for the traffic manager would do the trick.
The idea of traffic manager is simple, you can tell the traffic
manager to stand after the domain name ( domain name resolution of the
app ) then the traffic manager decides where to send the request on
considerations of factors like Round-Robin, Disaster Management etc.
With the combination of the Traffic Manager and multi-region infrastructure setup; you will march towards the high availability goal.
Links
Azure Traffic Manager Overview
Cloud Power: How to scale Azure Websites globally with Traffic Manager
Maybe You should configure a corosync cluster with DRBD ?
DRBD will ensure You that the data on both nodes are replicated (for example website files and db files).
Apache as web server will be available under a virtual IP to which domain is pointed. In case of one server is down corosync will move all services to second server within few seconds.